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Diese Arbeit untersucht die zielführende Gestaltung einer experimentellen, beschleunigten Alterungscharakterisierung von Lithium-Ionen-Zellen als initialer Schritt im Auslegungsprozess von Traktionsbatterien für Elektrofahrzeuge. In Versuchsreihen wird dazu die Relevanz von statischen und dynamischen Belastungen in den Betriebsmodi Parken, Laden und Fahren für die Zellalterung bewertet. Weiterhin werden Potentiale zur Beschleunigung der kalendarischen und zyklischen Alterung bezüglich deren Wirkung auf die beteiligten Alterungsmechanismen und -moden sowie die erreichbaren Beschleunigungsfaktoren evaluiert. This work investigates the target-oriented design of an experimental, accelerated aging characterization of lithium-ion cells as an initial step in the design process of traction batteries for electric vehicles. In various test series, the relevance of static and dynamic loads in the operating modes parking, charging, and driving for cell aging is evaluated. Furthermore, potentials for accelerating the calendar and cyclic aging are evaluated regarding their effect on the aging mechanisms and modes involved as well as the achievable acceleration factors.

Um die Effizienz selbstheilender Eigenschaften eines zementgebundenen Werkstoffes zuverlässig zu evaluieren, werden Mess- und Testverfahren validiert, welche den Prüfkörper dauerhaft und kontinuierlich über die volle Versuchsdauer zerstörungsfrei überwachen sollen. Dazu zählen u. a. Ultraschall, Schwingungsanalyse und Schallemissionsanalyse. Hergestellte Testserien vom Labormaßstab bis hin zu strukturellen Bauteilelementen mit verschiedenen Selbstheilungskonzepten werden dabei systematisch mit analytischen und eigens entwickelten Versuchsaufbauten untersucht. In order to reliably evaluate the self-healing efficiency of cementitious materials, test and monitoring techniques are being validated. Therefore, test specimens are permanently and continuously monitored over the full test duration in a non-destructive manner. These methods include i. a. ultrasound, vibration analysis and acoustic emission analysis. Test series ranging from lab scale to structural component elements with different self-healing concepts are systematically examined with analytical and self-developed test setups.

Das direkte Laserstrahlsintern von Metallpulvern (DMLS) ist ein Rapid Prototyping-Verfahren mit herausragender Stellung. In einem einstufigen Prozeß lassen sich Prototypen oder Prototypenwerkzeuge herstellen. Für die qualifizierte und beherrschte Anwendung muß das Verfahren in seinen Grundlagen besser verstanden werden. Hierzu wurde im Rahmen dieser Arbeit ein 3D-Prozeßmodell erarbeitet, die Einflüsse der prozeßbestimmenden Parameter auf Bauteileigenschaften laserstrahlgesinterter Werkstücke quantitativ sowie qualitativ erfaßt und eine prozeßangepaßte Systemtechnik zur Verringerung der beim Laserstrahlsintern eingebrachten Eigenspannungen entwickelt. Durch die im Rahmen dieser Arbeit ermittelten Bauteileigenschaften und deren qualitative Voraussage mittels des aufgestellten Prozeßmodells wird der Anwender in die Lage versetzt, die Eigenschaften der laserstrahlgesinterten Bauteile gezielt auf das gewünschte Anforderungsprofil abzustimmen. Dies wurde abschließend anhand von drei ausgewählten Anwendungen exemplarisch dargestellt., Direct laser beam sintering of metal powders (DMLS) is still a young rapid prototyping process with great economic potential. Prototypes or prototype tools can be produced in a one-step process. The basics of the process must be better understood for qualified and controlled application. This was the first time in this work that: - we developed a 3D process model that qualitatively describes the physical and material processes in the DMLS process. - the influences of the process-determining parameters on component properties of laser-beam sintered workpieces are quantitatively and qualitatively recorded. - we developed a process-adapted system technology to reduce the internal stresses introduced during laser beam sintering. Based on a structured process analysis, the three influencing factors laser beam, powder material and beam-material interaction were fundamentally characterized. The expansion of the knowledge gained with the analysis of the material properties of laser-sintered components provided the information to clarify the processes during laser beam sintering. Based on the understanding of laser beam internal in its entirety, a three-dimensional, physical process model was developed. During the first irradiation process, the powder material is converted into the solid, laser-sintered state. At the time the molten state occurs, there is adhesion to the surrounding substrate. The residual stresses are reduced during the subsequent irradiation. This modeling allows the effects on the characteristic component properties to be predicted qualitatively with a variation of the significant influencing parameters: - the scanning speed primarily determines the achievable strengths with a tendency towards higher strengths at lower scanning speeds. - the beam offset has a dominant influence on the internal stresses. An increase in the beam offset leads to greater tendencies to warp. Using the process model and practical test series, a process window for the powder material M Cu 2201 (components: Ni, CuSn, Cu-P and Cu3P) from EOS and the laser beam sintering system (manufacturer: EOS, type: EOSINT M 250) were determined. The surface energy introduced into the workpiece was determined as the main influencing factor. Mechanical properties, density, surface properties, tendency to warp and thermal stability of the components were characterized. As a result of the layered construction, laser-sintered workpieces have strongly anisotropic material properties. The changes in properties depending on the orientation to the normal of the building level, which amounted to up to 50% of the values of the mechanical component properties, could be predicted by the process model. Values for achievable mechanical component properties as a function of scan speed and beam offset are listed in Tables 7.3 and 7.4. A process window for which all the above-mentioned parameters reach an optimum does not exist. For example, an increase in strength is at the expense of the tendency to warp and good surfaces. To characterize the molded part geometry, the individual error sources were narrowed down and their effects were shown. The systematic analysis served as the basis for the development of an automatic calibration module, with the help of which the absolute inaccuracies could be reduced to a maximum of 0.15 mm and the relative to 0.15% of the total dimensions. This meant a 2.5-fold increase in dimensional accuracy compared to the uncalibrated delivery state of the investment. The temperature gradients between the interaction point and the surrounding, already sintered areas during the laser beam sintering led to internal stresses in the components, which in turn resulted in a distortion of the same. To reduce this effect, a flexible beam guidance and shaping system was developed. The raw beam emitted by the laser is divided into a focused working beam and a ring beam surrounding it, which is used to heat the surrounding powder bed. The comparison of workpieces, produced without and with process-adapted beam guidance, has shown that this concept of local preheating and postheating reduces the inherent stresses and the resulting distortion of the components by more than 50%. A specially developed test part was used, which allows the residual stresses introduced into the component by the laser beam sintering process to be determined quantitatively. In addition, the parts were significantly less warping even under thermal stress. Proof of this was provided by measurements of dimensional accuracy after heat treatments for a number of standardized components. The component properties determined in the course of this work and their qualitative prediction by means of the process model set up enable the user to tailor the properties of the laser-sintered components to the desired profile of requirements. Finally, this was exemplified using three selected applications. The possibility of quantitative predictions of the component properties is necessary for the further qualification of the laser beam internal. The extension of the physical process model to a quantitative description of the effects is an option. The use of FE analysis is suitable for support and expansion. The step-by-step structure of the 3D process model described in the present work represents a guideline for the development of numerical modeling. The component properties determined are available for the verification of the FE results. Furthermore, the material systems used offer great potential for improving the component properties of laser-sintered workpieces. The next step is to use steel as the low-melting component and to use a high-temperature resistant material such as tungsten as the high-melting component. In addition to this, the expansion of the system technology is a prerequisite, since the successful processing of oxidation-sensitive powder materials requires a reducing or inert atmosphere. The use of higher power laser beam sources enables the required higher process temperatures to be generated without reducing the scanning speed and thus the production time. By consistently implementing the results obtained, further areas of application can be opened up. Applications of laser beam internal e.g. for the production of molds for light metal die casting or for the forming technique or the production of electrodes for die sinking EDM are currently still in the research stage [REI97, GEI97]. However, you can already expect further technical and economic potential for industrial use., Fertigungstechnik - Erlangen, 93

Die Baugruppenfertigung ist geprägt von einem weltweit stark dynamischen Wachstum in allen Bereichen. Elektronikproduktion als Schlüsseltechnologie und Kernkompetenz ist von herausragender Bedeutung für den Wirtschaftsstandort Deutschland. Die Qualitätssicherung hat dabei einen besonderen Stellenwert. Dies zeigt sich am vergleichsweise hohen Aufwand für Personal und Investitionen mit entsprechenden Kosten. Ursachen liegen in der Komplexität der Prozessschritte, verstärkt durch zunehmende Miniaturisierung sowie der stetigen Erhöhung der Anzahl an Verbindungsstellen pro Bauelement. Die zunehmende Variantenvielfalt heutiger Elektronikkomponenten führt jedoch zwangsläufig zu komplexeren und flexibleren Prozessketten. Die Integration neuer Komponenten bei gleichzeitigem Zwang zu qualitäts- und kostenoptimalen Fertigungslösungen führt zu erweiterten Herausforderungen an die Qualitätssicherung. Ziel der Arbeit war daher die gezielte Analyse qualitäts- und kostenrelevanter Mechanismen innerhalb eines erweiterten Produktionsumfeldes für miniaturisierte Strukturen. Dabei wurden zu Beginn der Untersuchungen die verschiedenen Alternativen zur Standard-SMD-Technologie gegenübergestellt und hinsichtlich ihrer technologischen Umsetzung vergleichend bewertet. Es zeigt sich, dass die kostengünstigste Lösung zur Funktionsintegration auf Baugruppenebene mit BGAs und CSPs realisiert werden kann. Beide Bauelementtypen sind der Gruppe der Area Arrays zuzuordnen und besitzen ,insbesondere bei der Integration in bestehende Prozessketten, wirtschaftliche und technologische Vorteile. Ausgehend von dieser Vorauswahl wurde eine umfangreiche technische Qualifizierung der am Lehrstuhl verfügbaren Systeme zur Verarbeitung von Area Arrays durchgeführt. Für die einzelnen Teilprozesse Lotpastenauftrag, Bestücken, Löten wurden die ausgewählten Maschinen experimentell untersucht und wesentliche Stellparameter analysiert. Daraufhin wurden Optimierungsmaßnahmen entwickelt und deren Wirksamkeit durch Fähigkeitsanalysen nachgewiesen. Diese Ergebnisse konnten zudem auf die Qualifizierung bestehender Systeme bei Industriepartnern im Rahmen von Kooperationen übertragen werden. Aufbauend auf diesen Arbeiten konnte erstmals eine Prozesskette zur Verarbeitung höchstintegrierter Bauelemente mit verdeckten Anschlussstrukturen am Institut aufgebaut werden. Diese Präzisionsprozesskette diente zur umfassenden Analyse von Wechselwirkungen und Schädigungsmechanismen bei der Verarbeitung von Area Arrays. Der starke Einfluss anschlussspezifischer Kenngrößen auf die Prozessqualität konnte ebenso nachgewiesen werden, wie die deutliche Abhängigkeit der Verarbeitbarkeit dieser Bausteine von bisher nur unzureichend berücksichtigten Parameter wie der Bestückkraft. Ergänzend wurden im Vorfeld verschiedene Versuchsreihen zur Charakterisierung des Benetzungsverhaltens unter Lagerungseinfluss durchgeführt. Hier zeigte sich das signifikant bessere Benetzungsverhalten von Area Arrays gegenüber technologisch vergleichbaren Bausteinen mit peripheren Anschlüssen. Zur übergreifenden Analyse der Wechselwirkungsbeziehungen wurde ein am Institut entwickeltes Informationssystem um die technologisch relevanten Komponenten, Prozesse und Analysemechanismen ausgebaut. Gleichzeitig wurde der Aspekt der Nacharbeit durch die Integration zusätzlicher Funktionalitäten berücksichtigt. Insbesondere vor dem Hintergrund neuer und miniaturisierter Anschlussformen muss eine prozessintegrierte Nacharbeit bereitgestellt werden. Hierzu wurden erste Arbeiten geleistet, die in Zusammenarbeit mit Industriepartnern ausgebaut werden. Mit fortschreitender Erhöhung der Qualitätsniveaus erhält die Frage nach dem Aufwand für eine beherrschte Fertigung zunehmend an Bedeutung. Die rein technische Betrachtung und Optimierung eines Prozesses muss um Parameter zur Abschätzung des wirtschaftlichen notwendigen Aufwandes ergänzt werden. In umfangreichen Grundlagenuntersuchungen wurden daher marktverfügbare Systeme zur integrierten Qualitäts und Kostenbewertung evaluiert und aus deren Defizite ein Anforderungsprofil für die spezifischen Belange der Elektronikproduktion abgeleitet. Dieses Profil wurde in einem zweistufigen Bewertungssystem umgesetzt, mit dem sowohl eine Technologiewechselbewertung als Planungswerkzeug wie auch eine produktionsintegrierte Effizienzbewertung möglich ist. Exemplarische Anwendungsbeispiele sowie die Anbindungsmöglichkeiten an externe Systeme verdeutlichen die vielfältigen Einsatzfälle, die das realisierte Bewertungssystem zur Effizienzanalyse zur Verfügung stellt. In zukünftigen Arbeiten werden die Verarbeitungsmechanismen für innovative Bauelementformen weiter verfeinert und zusätzlich alternative Verbindungsmedien oder Substrate berücksichtigt. Darüber hinaus bietet die konsequente Zusammenführung von Qualitäts- und Kostenaspekten bei Planung, Realisierung und Betrieb komplexer Fertigungslinien zur Baugruppenproduktion noch erhebliches Potential, das in weiterführenden Arbeiten umzusetzen ist., The assembly production is characterized by a strongly dynamic growth in all areas worldwide. Electronics production as a key technology and core competence is of outstanding importance for Germany as a business location. Quality assurance is of particular importance. This can be seen from the comparatively high expenditure for personnel and investments with corresponding costs. The causes lie in the complexity of the process steps, reinforced by increasing miniaturization and the steadily increasing number of connection points per component. However, the increasing variety of today's electronic components leads inevitably lead to more complex and flexible process chains. The integration of new components while at the same time being forced to produce quality and cost-effective manufacturing solutions leads to expanded quality assurance challenges. The aim of the work was therefore the targeted analysis of quality and cost-relevant mechanisms within an expanded production environment for miniaturized structures. At the beginning of the investigations, the various alternatives to standard SMD technology were compared and their technological implementation was compared. It turns out that the most cost-effective solution for functional integration at the component level can be implemented with BGAs and CSPs. Both types of components can be assigned to the group of area arrays and have economic and technological advantages, especially when integrated into existing process chains. Based on this pre-selection, extensive technical qualification of the systems available at the chair for processing area arrays was carried out. For the individual sub-processes of solder paste application, assembly, soldering, the selected machines were experimentally examined and essential control parameters were analyzed. As a result, optimization measures were developed and their effectiveness demonstrated by ability analyzes. These results could also be transferred to the qualification of existing systems at industrial partners within the framework of cooperations. Building on this work, a process chain for processing highly integrated components with hidden connection structures could be set up at the institute for the first time. This precision process chain was used for the comprehensive analysis of interactions and damage mechanisms when processing area arrays. The strong influence of connection-specific parameters on the process quality could also be demonstrated, as well as the clear dependence of the processability of these modules on parameters that were previously insufficiently considered, such as the placement force. In addition, various test series were carried out beforehand to characterize the wetting behavior under the influence of storage. This showed the significantly better wetting behavior of area arrays compared to technologically comparable modules with peripheral connections. For a comprehensive analysis of the interaction relationships, an information system developed at the institute was expanded to include the technologically relevant components, processes and analysis mechanisms. At the same time, the aspect of rework was taken into account by integrating additional functionalities. Process-integrated rework must be provided, especially against the background of new and miniaturized connection forms. To this end, initial work has been carried out, which will be expanded in cooperation with industrial partners. As the level of quality increases, the question of the effort required for controlled production is becoming increasingly important. The purely technical consideration and optimization of a process must be supplemented by parameters to estimate the economically necessary effort. Comprehensive basic investigations therefore evaluated market-available systems for integrated quality and cost assessment and derived a requirement profile for the specific interests of electronics production from their deficits. This profile was implemented in a two-stage evaluation system, which enables both a technology change evaluation as a planning tool and a production-integrated efficiency evaluation. Exemplary application examples and the connection options to external systems illustrate the diverse applications that the implemented evaluation system provides for efficiency analysis. In future work, the processing mechanisms for innovative component shapes will be further refined and alternative connection media or substrates will also be taken into account. In addition, the consistent merging of quality and cost aspects in the planning, implementation and operation of complex production lines for module production still offers considerable potential that must be implemented in further work., Fertigungstechnik - Erlangen, 112

Die Vorhersage der Werkzeuglebensdauer und -Zuverlässigkeit zu einem frühen Zeitpunkt der Entwicklungsphase ist eine wesentliche Voraussetzung für die richtige Dimensionierung des Werkzeugsystems und die Bewertung von Optimierungsmaßnahmen. Die bislang bekannten Möglichkeiten der Versagenssimulation beschränkten sich im Prinzip auf die Lokalisierung der versagenskritischen Werkzeugbereiche sowie auf die Abschätzung der mittleren Werkzeuglebensdauer. Aufgabe und Gegenstand der vorliegenden Forschungsarbeit war es, die Werkzeuglebensdauervorhersage um die Angabe der statistischen Verteilung der Ausfallwahrscheinlichkeit zu erweitern. Die Prognostizierung von derart attributierten Lebensdauerdaten bildet die Grundlage für geringere, gleichzeitig vorhersagbare und damit planbare Maschinenstillstandszeiten. Weiterhin führen höhere Lebensdauerwerte zu einer Reduzierung des Werkzeugkostenanteils an den Produktionskosten. Ein geeignetes Planungsinstrument für die simulationsbasierte Werkzeuglebensdauervorhersage ist das Konzept der Gegenüberstellung von Werkzeugbeanspruchung und -beanspruchbarkeit. Es handelt sich dabei um einen deterministisch-probabilistischen Ansatz, mit dem die numerische Simulation des Umformprozesses, die Modellierung spezifischer Versagensmechanismen und statistische Verfahren wie die Interferenzanalyse miteinander verbunden werden. Mit den statistischen Verfahren werden die Unsicherheiten und die Streuungen der primären Prozeßeinflußgrößen erfaßbar, die letztlich die Ursache für die ausgeprägte Lebensdauerstreuung darstellen. Um einen Ansatz dieser Art auf reale Problemstellungen anwenden zu können, mußten zunächst eine Reihe von Voraussetzungen erfüllt sein. Es waren dies zunächst statistisch abgesicherte Kennwerte zur Beschreibung des Ermüdungsverhaltens des jeweiligen Werkzeug Werkstoffs. Weiterhin waren auf der Grundlage der Ermüdungskennwerte Schädigungskonzepte weiterzuentwickeln bzw. bereits verfügbare Schädigungskonzepte hinsichtlich ihrer Leistungsfähigkeit und universellen Anwendbarkeit für die Lebensdauerberechnung zu überprüfen. Unabhängig vom gewählten Schädigungskonzept und den in diesem Zusammenhang herangezogenen Ermüdungskennwerten bilden zuverlässige Daten zur Quantifizierung der Werkzeugbeanspruchung letztlich die Basis jeder Lebensdauerberechnung. Mit Blick auf die genannte Zielsetzung waren daher die angesprochenen Problemstellungen zu klären, woraus eine Reihe von Arbeitspunkten resultierte, deren Inhalte und Ergebnisse im folgenden zusammengefaßt werden. Es konnte zunächst anhand unterschiedlicher Anwendungsbeispiele nachgewiesen werden, daß sich die Simulationsmodelle sowohl meßtechnisch als auch numerisch überprüfen lassen. Grundsätzlich können auch bei einer anwendungsorientierten Vorgehensweise Konvergenzanalysen zur Abschätzung der exakten Beanspruchungshöhe im Werkzeug vorgenommen werden. Dennoch bestehende Diskrepanzen zwischen den berechneten und den in der Realität, d.h. unter Produktionsbedingungen auftretenden Lebensdauerwerten, sind i.d.R. darauf zurückzuführen, daß das reale Werkzeugverhalten im Simulationsmodell nicht korrekt wiedergegeben wird. Eine vergleichsweise einfache Methode, die sich für die Modellüberprüfung als geeignet erwiesen hat, basiert auf lokalen Dehnungsmessungen an der Matrize bzw. an den Armierungsringen. Dabei können auch Effekte erkannt werden, die zu einer unbeabsichtigten und daher unerwarteten Verringerung der radialen Vorspannung führen. Weiterhin wurde die Fragestellung der korrekten Beschreibung mehrachsiger Beanspruchungszustände im Werkzeug und deren Reduzierung auf eine einparametrige Vergleichsbeanspruchung, beispielsweise durch die Anwendung eines energetischen Schädigungskonzeptes, erneut aufgegriffen. Die durchgeführten Untersuchungen haben gezeigt, daß der universelle Charakter des energetischen Schädigungskonzeptes im Einzelfall von der Art der Beanspruchungen eingeschränkt wird. Zudem erfordert die korrekte Anwendung des energetischen Konzeptes, d.h. die Berücksichtigung hydrostatischer Schädigungsanteile, hinreichend genaue Angaben über den Spannungs- und Dehnungszustand der Versuchsproben, die zur Bestimmung der Ermüdungskennwerte herangezogen wurden. Im allgemeinen stehen derartige Informationen nicht oder nur in eingeschränkter Form zur Verfügung. Die meisten Versagensfälle lassen sich jedoch auf eine einachsige Beanspruchung (z.B. Mode I-Beanspruchung) zurückführen, so daß die Lebensdauervorhersage auf Basis des einfacher zu handhabenden lokalen Dehnungsansatzes durchgeführt werden kann. Beide Schädigungsansätze sind mit dem grundsätzlichen Nachteil behaftet, daß Oberflächen- und Größeneinflüsse nicht explizit berücksichtigt werden. Es ergab sich daher die Notwendigkeit einen Ansatz vorzuschlagen, der die Größe des versagenskritisch beanspruchten Volumens in die Lebensdauerberechnung integriert. Die bislang vorliegenden Ergebnisse zeigen bereits die Leistungsfähigkeit dieses Ansatzes auf. Sie sollten jedoch anhand weiterer Anwendungsbeispiele überprüft werden, wobei insbesondere die Werkstoffkennwerte zur Quantifizierung der Volumenabhängigkeit der Ermüdungsfestigkeit durch weitere Versuchsreihen abzusichem sind. Mit der vorliegenden Arbeit wurde erstmals ein Konzept für die Werkzeuglebensdauervorhersage angewendet, das die numerische Beanspruchungsanalyse mit statistischen Methoden verknüpft und somit die Lebensdauervorhersage um die Prognostizierung des stochastischen Ausfallcharakters erweitert. Die in der Realität auftretende Lebensdauerstreuung konnte dabei auf die Streuungen der Beanspruchung, bestimmt durch Unsicherheiten der statischen und dynamischen Prozeßeinflußgrößen, und der Beanspruchbarkeit zurückgeführt werden. Für das ausgewählte Anwendungsbeispiel zeigte sich, daß dynamische Prozeßeinflußgrößen, wie die Fließspannung des Werkstückstoffs, für die Lebensdauerstreuung von untergeordneter Bedeutung sind. Der Einfluß der statischen Prozeßeinflußgrößen, hierunter ist primär das geometrische Vorspannmaß zwischen Matrize und Armierung zu zählen, konnte u.a. auch für bandarmierte Werkzeugsysteme nachgewiesen werden und dürfte insbesondere bei konventionellen Armierungssystemen in seiner Bedeutung noch zunehmen. Dennoch verdeutlichen die Ergebnisse der Interferenzanalysen, bzw. deren Vergleich mit den beobachteten Lebensdauerdaten, daß die ausgeprägten Lebensdauerstreuungen primär auf das Ermüdungsverhalten des Werkzeugwerkstoffs zurückgeführt werden können. Zusammenfassend ist festzustellen, daß die numerische Prozeßsimulation einen Entwicklungsstand erreicht hat, der eine hinreichend genaue Berechnung der Werkzeugbeanspruchung und damit eine Vorhersage der Werkzeuglebensdauer zuläßt. Darüber hinaus kann durch eine Variation der Werte der signifikanten Prozeßeinflußgrößen der funktionale Zusammenhang zur Werkzeugbeanspruchung aufgestellt werden. Dieser bildet die Basis für die Sensitivitätsanalyse und ermöglicht letztlich eine Berechnung der Lebensdauerstreuung bzw. der damit verbundenen statistischen Verteilungsfunktion. Die angewandte Methodik ist dadurch charakterisiert, daß einerseits die Durchführung der Variationsrechnungen mit einem hohen Rechenzeitbedarf verbunden ist, und andererseits die Ermüdungskennwerte zur stochastischen Beschreibung der Beanspruchbarkeit im allgemeinen nicht in der erforderlichen Qualität verfügbar sind. Während der erste Gesichtspunkt mit fortschreitender Entwicklung der Rechnerleistung zunehmend an Bedeutung verliert, konnten die bislang nur unzureichend verfügbaren Daten zur Charakterisierung der Ermüdungsfestigkeit für ausgewählte Werkzeugstähle im Rahmen dieser Arbeit ebenfalls bereitgestellt werden., The prediction of tool life and reliability at an early stage in the development phase is an essential prerequisite for the correct dimensioning of the tool system and the evaluation of optimization measures. The previously known possibilities of failure simulation were limited in principle to the localization of the tool areas critical to failure and to the estimation of the average tool life. The task and subject of the present research work was to extend the tool life prediction by the specification of the statistical distribution of the failure probability. The forecasting of such attributed service life data forms the basis for lower, and at the same time foreseeable and therefore predictable machine downtimes. Furthermore, higher service life values lead to a reduction of the tool cost share in the production costs. A suitable planning tool for the simulation-based tool life prediction is the concept of the comparison of the actual tool stress and it`s stress resistance. It is a deterministic-probabilistic approach that combines the numerical simulation of the forming process, the modeling of specific failure mechanisms and statistical methods such as interference analysis. The statistical methods make it possible to measure the uncertainties and the spread of the primary process influencing variables, which ultimately represent the cause of the pronounced spread of the service life. In order to apply an approach of this kind to real problems, a number of prerequisites had to be met. Initially, these were statistically verified parameters to describe the fatigue behavior of the respective tool material. Furthermore, on the basis of the fatigue parameters, damage concepts had to be further developed or damage concepts already available had to be checked with regard to their performance and universal applicability for the service life calculation. Irrespective of the selected damage concept and the fatigue parameters used in this context, reliable data for quantifying the tool stress ultimately form the basis of any service life calculation. With a view to the stated objective, the problems addressed had to be clarified, which resulted in a number of working points, the contents and results of which are summarized below. It was first possible to demonstrate using different application examples that the simulation models can be checked both in terms of measurement technology and numerically. In principle, even with an application-oriented approach, convergence analyzes can be carried out to estimate the exact level of stress in the tool. However, there are discrepancies between the calculated and the real, i.e. Lifetime values occurring under production conditions are usually attributable to the fact that the real tool behavior is not reproduced correctly in the simulation model. A comparatively simple method, which has proven to be suitable for the model check, is based on local strain measurements on the die or on the reinforcement rings. Effects can also be identified that lead to an unintentional and therefore unexpected reduction in the radial preload. Furthermore, the question of the correct description of multi-axis stress conditions in the tool and its reduction to a one-parameter comparative stress, for example by using an energetic damage concept, was taken up again. The investigations carried out have shown that the universal character of the energetic damage concept is limited in individual cases by the type of stress. In addition, the correct application of the energetic concept, i.e. the consideration of hydrostatic damage, sufficiently precise information about the stress and strain state of the test samples, which were used to determine the fatigue parameters. In general, such information is not available or is only available to a limited extent. Most failures can, however, be traced back to a uniaxial stress (e.g. Mode I stress), so that the service life prediction can be carried out based on the easier to use local strain approach. Both damage approaches have the fundamental disadvantage that surface and size influences are not explicitly taken into account. Therefore, there was a need to propose an approach that integrates the size of the failure-critical volume into the service life calculation. The results so far already show the effectiveness of this approach. However, they should be checked on the basis of further application examples, in particular the material properties for quantifying the volume dependence of the fatigue strength must be verified by further test series. With the present work, a concept for tool life prediction was used for the first time, which links the numerical stress analysis with statistical methods and thus extends the life expectancy with the prediction of the stochastic failure character. The life-time variance that occurred in reality could be traced back to the variance of the stress, determined by the uncertainties of the static and dynamic process influencing variables, and the stressability. For the selected application example, it was found that dynamic process influencing variables, such as the yield stress of the workpiece material, are of minor importance for the lifetime scatter. The influence of the static process influencing variables, which primarily includes the geometrical prestressing dimension between the die and the reinforcement, could also be demonstrated for band-armored tool systems and its importance is likely to increase, particularly in the case of conventional armoring systems. Nevertheless, the results of the interference analyzes, or their comparison with the observed service life data, make it clear that the pronounced spread of the service life can primarily be attributed to the fatigue behavior of the tool material. In summary, it can be stated that the numerical process simulation has reached a state of development that allows a sufficiently precise calculation of the tool load and thus a prediction of the tool life. In addition, the functional relationship to tool stress can be established by varying the values of the significant process influencing variables. This forms the basis for the sensitivity analysis and ultimately enables a calculation of the lifetime spread or the associated statistical distribution function. The methodology used is characterized in that on the one hand the execution of the variation calculations is associated with a high computing time requirement and on the other hand the fatigue parameters for the stochastic description of the loadability are generally not available in the required quality. While the first point of view is becoming less and less important as computer performance continues to develop, the data to characterize the fatigue strength for selected tool steels, which has hitherto been insufficiently available, could also be provided as part of this work., Fertigungstechnik - Erlangen, 100

Auf Grund der zunehmenden Produkt- und Prozeßkomplexität in der Elektronikfertigung wird die sichere Beherrschung der Fertigungstechnologien ein immer wichtig werdender Wettbewerbsfaktor, um eine kostengünstige Herstellung der elektronischen Baugruppen bei einem hohen Qualitätsniveau zu garantieren. Die Verbindungstechnik stellt dabei einen zentralen Verfahrensschritt in der Produktionskette dar. Ziel der Arbeit war, aufbauend auf eine gesamtheitliche Analyse des Systems Lötverbindung unter Einbeziehung der beteiligten Materialien, Anlagen und Prozesse, einen Beitrag zur Qualitätssteigerung in der Elektronikproduktion zu leisten. Ein Schwerpunkt lag dabei auf der Technologie der räumlichen, spritzgegossenen Schaltungsträger (3-D MID), die auf Grund des Einsatzes thermoplastischer Substratmaterialien und der dreidimensionalen Ausprägungen des Basisteils neue Anforderungen an die Verbindungstechnik stellen. Im ersten Teil dieser Arbeit wurden Technologieuntersuchungen zum Bereich der Lötstellenausbildung vorgestellt. Diese konzentrierten sich auf die Bauteilpositionierung auf den Anschlußflächen während des Reflowprozesses und auf die innere Struktur der Lötverbindungen. Mit Hilfe der Visualisierung des Lötprozesses konnten einerseits präventive Qualitätssicherungsmaßnahmen zur Förderung des Selbstzentriereffektes als auch Strategien zur Vermeidung von Verdrehfehlern bei SMT-Bauteilen aufgezeigt werden. Der Einsatz der Röntgentechnik zur Prozeßüberwachung ermöglichte den Einfluß verschiedener Material- und Prozeßparameter auf die Porenbildung zu detektieren und daraus Maßnahmen zur Optimierung der Prozeßführung abzuleiten. Damit sind wichtige Grundlagen zur Erhöhung der Lötstellenqualität erarbeitet worden. Für die zunehmende Variantenvielfalt wurde im Bereich der Anlagentechnik ein temperaturgeregeltes Infrarotlötsystem aufgebaut und dessen Eignung für das Verlöten unterschiedlicher Schaltungsträgergeometrien verifiziert. Da das Wissen über die Einsatzmöglichkeiten der konventionellen Verbindungstechnik für die MID-Technik noch sehr gering ist, wurde erstmals eine systematische Prozeßqualifizierung thermoplastischer Substratmaterialien durchgeführt. Hierzu wurde eine mehrstufige Vorgehensweise entwickelt, die eine Analyse des gesamten Verbundsystems Kunststoff-Metallschicht-Bauelementverbindung beinhaltete. Durch die verschiedenen Untersuchungen zur thermischen Belastbarkeit der Substrate, zur Haftung der Metallschichten und zur Charakterisierung der Lötqualität wurde die Einsatzfähigkeit unterschiedlicher Material- und Verfahrenskombinationen für die SMD-Technik nachgewiesen. Dabei wurden auch die Auswirkungen verschiedener Einflußgrößen in der Produktionskette der MID-Baugruppen auf das Lötergebnis experimentell bestimmt und daraus Verarbeitungshinweise für den Anwender der MID-Technologie vorgeschlagen. Auf Grund der begrenzten Warmformbeständigkeit von Kunststoffen wurden verschiedene Lösungen zur Erweiterung des verarbeitbaren Spektrums an Thermoplasten als Substratmaterial für elektrische Schaltungen analysiert. So hat sich die Verwendung niederschmelzender Lotpasten sowie der Einsatz selektiver Lötverfahren als geeignet erwiesen, die Temperaturbelastung für die Kunstoffe abzusenken. Wie die Untersuchungen zur Lötqualität bestätigten, stehen mit diesen Verfahren Alternativen zu den Standardlöttechniken für die MID-Technologie zur Verfügung. Neben den Verarbeitungseigenschaften stellt die Langzeitzuverlässigkeit ein entscheidendes Kriterium für den Einsatz von MID-Baugruppen in den verschiedenen Anwendungsgebieten dar. Hierzu wurden beschleunigte Alterungstests durchgeführt, die erste wichtige Erkenntnisse zur Ausfallrate und zu den Ausfallmechanismen auf thermoplastischen Schaltungsträgern ergaben. Daraus wurden Maßnahmen zur Verbesserung des Langzeitverhaltens durch Auswahl faserverstärkter Kunststoffe sowie durch Änderungen des Schaltungslayouts entwickelt und experimentell überprüft. An einem auf der Basis dieser Erkenntnisse ausgewählten MID- Produkt konnte der Nachweis der praktischen Einsatzfähigkeit des Schaltungsträgeraufbaus für die geforderten Einsatzbedingungen erbracht werden. Die räumliche Gestaltung der MID-Baugruppen stellt auch für die Lötsysteme eine neue Herausforderung dar. Anhand unterschiedlicher, geometrischer Ausprägungen von dreidimensionalen Schaltungsträgern konnte auf der Basis zahlreicher Untersuchungen eine Bewertung der verschiedenen Erwärmungsmethoden und Anlagenkonzepte für das Reflowlöten von räumlichen Schaltungsträgern durchgeführt werden. Die Möglichkeiten der MID-Technik SMD-Bauteile auf geneigten Prozeßebenen anzuordnen, stellt auf Grund des zusätzlichen Einflusses der Gravitation erhöhte Anforderungen an die Prozeßführung. Aus den Ergebnissen umfangreicher Testreihen wurden Kriterien für die konstruktive Gestaltung des Kunststoffträgers entwickelt sowie die Anforderungen an die beteiligten Fügepartner definiert. Die aus sämtlichen Untersuchungen gewonnenen Erkenntnisse im Bereich der Verbindungstechnik für räumliche Schaltungsträger wurden für zukünftige Anwender der MID-Technologie in Richtlinien abschließend zusammengefaßt. Darüberhinaus bietet der Einsatz der MID-Technik durch die spritzgußtechnische Herstellung der Schaltungsträger noch erhebliche Rationalisierungspotentiale in der Montage beispielsweise durch Realisierung neuer Kontaktierungsmöglichkeiten, die ergänzend diskutiert werden und in weiterführenden Arbeiten zu erproben sind., Due to the increasing product and process complexity in electronics manufacturing, the mastery of manufacturing technologies is becoming an increasingly important competitive factor in order to guarantee cost-effective production of electronic assemblies with a high level of quality. The connection technology represents a central process step in the production chain. The aim of the work was to contribute to increasing quality in electronics production based on a holistic analysis of the soldered connection system, including the materials, systems and processes involved. One focus was on the technology of spatial, injection-molded circuit carriers (3-D MID), which place new demands on the connection technology due to the use of thermoplastic substrate materials and the three-dimensional characteristics of the base part. In the first part of this work, technology studies on the area of solder joint formation were presented. These focused on component positioning on the pads during the reflow process and on the internal structure of the solder joints. With the help of the visualization of the soldering process, preventive quality assurance measures to promote the self-centering effect as well as strategies to avoid twisting errors in SMT components were shown. The use of X-ray technology for process monitoring made it possible to detect the influence of various material and process parameters on pore formation and to derive measures for optimizing the process control. In this way, important foundations for increasing the solder joint quality have been developed. For the increasing variety of variants, a temperature-controlled infrared soldering system was set up in the area of system technology and its suitability for soldering different circuit carrier geometries was verified. Since the knowledge of the possible uses of conventional connection technology for MID technology is still very low, systematic process qualification of thermoplastic substrate materials was carried out for the first time. For this purpose, a multi-stage procedure was developed, which included an analysis of the entire composite system plastic-metal layer-component connection. The various investigations into the thermal load-bearing capacity of the substrates, the adhesion of the metal layers and the characterization of the soldering quality have demonstrated the suitability of different material and process combinations for SMD technology. The effects of various influencing factors in the production chain of the MID assemblies on the soldering result were also determined experimentally and processing instructions for the user of the MID technology were suggested. Due to the limited heat resistance of plastics, various solutions for expanding the processable spectrum of thermoplastics as a substrate material for electrical circuits were analyzed. The use of low-melting solder pastes and the use of selective soldering processes have proven to be suitable for reducing the temperature load on the plastics. As the investigations on soldering quality confirmed, these methods provide alternatives to the standard soldering techniques for MID technology. In addition to the processing properties, long-term reliability is a decisive criterion for the use of MID modules in the various areas of application. For this purpose, accelerated aging tests were carried out, which gave important insights into the failure rate and the failure mechanisms on thermoplastic circuit carriers. From this, measures to improve the long-term behavior by selecting fiber-reinforced plastics and by changing the circuit layout were developed and experimentally checked. On a MID product selected on the basis of these findings, it was possible to demonstrate the practical usability of the circuit carrier structure for the required operating conditions. The spatial design of the MID assemblies also poses a new challenge for the soldering systems. Based on various geometrical forms of three-dimensional circuit boards, an evaluation of the various heating methods and system concepts for reflow soldering of spatial circuit boards could be carried out on the basis of numerous studies. The possibilities of MID technology to arrange SMD components on inclined process levels places increased demands on process control due to the additional influence of gravity. From the results of extensive test series, criteria for the constructive design of the plastic carrier were developed and the requirements for the joining partners involved were defined. The knowledge gained from all investigations in the field of connection technology for spatial circuit carriers was finally summarized in guidelines for future users of MID technology. In addition, the use of MID technology through the injection molding of the circuit carriers still offers considerable rationalization potential in assembly, for example by realizing new contacting options, which are also discussed and to be tested in further work., Fertigungstechnik - Erlangen, 78

Die Dissertation behandelt die Einsatzmöglichkeiten von vollverschlossenen Seilen als Hänger in Stabbogenbrücken. Das Ermüdungsverhalten dieser Seile unter Wechselbeanspruchungen aus Normalkraft und Biegung im Seilendbereich wurde hierzu in zwei Versuchsreihen experimentell und mittels eines Seilmodells rechnerisch untersucht. Der lebensdauerbestimmende Schädigungsmechanismus (Reibkorrosion) konnte dadurch identifiziert und beschrieben werden. Für die Anwendung wird abschließend ein praxistaugliches Nachweisverfahren vorgeschlagen. The thesis treats the use of locked coil ropes as hangers in tied arch bridges. The fatigue behaviour of these ropes under alternating stress due to normal forces and bending close to the castings was examined both experimentally in two test series and through calculation. It was hereby possible to identify and describe the associated damage mechanism determining their service life (fretting corrosion). Finally, a design method for the engineering practice is suggested.

Die vorliegende Arbeit befasst sich mit Feuchtetransportvorgängen und den daraus resultierenden Beanspruchungen im Holz. Ziel der Untersuchungen ist es, baupraktische Klimaszenarien mit einer Delaminierungsprüfung anhand des holzartenspezifischen Verhaltens zu vergleichen. Die messtechnische Erfassung des Feuchtetransportverhaltens von sechs Holzarten dient der Bestimmung von Diffusionskennwerten. Die Messbilder eines optischen Messsystems visualisieren die Deformationen bei Feuchtewechseln. Anschließende FE-Berechnungen basieren auf diesen Versuchsreihen. The present thesis deals with moisture transport and the resulting internal load in timber. The scope of research studies has been to compare the moisture related behavior of wood species under the conditions of a delamination test to that of wood species subjected to service conditions in buildings. Measurement of the moisture transport behavior of six wood species serves as the basis for the determination of the diffusion coefficients. Images of an optical measurement system are used to visualize the deformations from moisture change. FE-models are then computed based upon the test series.

Im Rahmen der Arbeit wird im ersten Schritt die Technik eines herkömmlichen Head up-Displays analysiert und es werden Vorraussetzungen für die Realisierung eines kontaktanalogen Systems ermittelt. Verschiedene Möglichkeiten zur Umsetzung eines solchen kontaktanalogen Head-up-Displays werden generiert und bewertet; die Variante mit dem größten Potenzial wird als Prototyp aufgebaut und in einen Versuchsträger integriert. Sowohl die ausgewählte Technik als auch das implementierte Anzeigekonzept werden in einer abschließenden Versuchsreihe validiert. Ziel der Arbeit ist es, ein vollständiges Konzept für die Umsetzung eines kontaktanalogen Head up Displays im Fahrzeug zu erstellen und Impulse für die Weiterentwicklung zu geben. Within this dissertation the state of technology for conventional head-up-displays is analysed in a first step; further the requirements for the realisation of a location-correct head-up-display are being identified. Several possibilities for the realisation of such a location-correct head-up-display are being generated and evaluated; the type with the highest potential is being built up as a prototype and integrated in an experimental vehicle. Both the choosen technology and the implemented concept for the displayed information are being evaluated in a final test series. The intent of this dissertation is the development of a complete concept for the realisation of a location-correct head-up-display for vehicles and the formulation of suggestions for the further development.

The effectiveness of geogrids as means of soil reinforcement is well known. Due to complex interaction mechanisms between soil and geogrids, however, the stress strain behaviour of the composite material “geogrid reinforced soil” is still hard to predict. The identification of major material parameters and the description of their effect to the compound behaviour is therefore of great importance. Within this thesis geogrid reinforced soil has been investigated in the laboratory with large scale “element” tests, such as triaxial and biaxial compression tests. Especially the apparatus developed for the plane strain testing of 800mm wide specimens allows testing of soil reinforced with common geogrids with aperture widths of 30 to 40mm. Test series have been carried out to investigate the effect of certain material parameters, i.e. soil density, stress level and tensile stiffness of the geogrids, to the composite material behaviour. Thereby attention has been paid to vary only one parameter at a time to allow the exact assignment of the observed effects to the changes in the stress strain behaviour of the compound material. In contrast to the stress strain behaviour of unreinforced soil test results have shown an initially increasing stiffness of the composite material under vertical compression. This is caused by a gradual activation of the geogrids due to the lateral specimen extension. Furthermore, the reinforcing or confining effect of the geogrids has been identified to be higher at lower stress levels where there is only little confinement within the soil itself. A good compaction of the filling soil as well as a higher tensile stiffness have shown to lead to an increase of both the stiffness and the bearing capacity of the reinforced soil. Apart from the possibility of testing of large specimens the apparatus that has been constructed specifically for the investigation of the reinforced soil under plane strain conditions allows the determination of the kinematic behaviour of the reinforced soil. This is achieved by recording the movement of soil particles through a transparent side wall of the test apparatus during testing and a subsequent evaluation using the digital image correlation (DIC) method. Evaluating displacements and rotations of soil particles the development of arching effects and shear zones within the soil has been visualized. Following the idea of the “confining effect concept” the corresponding stress paths of the materials investigated with biaxial compression tests have been determined. From the equations given in this thesis the additional confining pressure due to the geogrid activation can be calculated for any loading state as a function of the tensile stiffness of the geogrids employed in the tests. In addition to the experimental tests numerical calculations of the biaxial compression tests have been carried out using the finite element method. The calculation results show an excellent match of the kinematic behaviour of unreinforced and geogrid reinforced specimens determined with the lab tests. Using a constitutive law with stress dependant description of the soil stiffness even the initial increase of the stiffness of the composite material during loading could be modeled. Calculations with a constant stiffness value, however, lead to a significant overestimation of the deformations of the composite material at the peak stage. Apart from the fundamental “element”-testing of the composite material also model tests have been carried out to investigate the development of earth pressure and connection loads within the reinforced soil. The cross section of the specimens investigated was 1000mm x 1000mm (H x W). The results have shown a significant reduction of the earth pressure even below the active earth pressure of the unreinforced soil. It has to mentioned that the earth pressure reduction occurred already at very small displacements of the wall facing, similar to or even less as those required for the development of the active earth pressure. Furthermore, it has been shown that the decrease of the earth pressure was apparent under the topmost reinforcement layer, independent of the height of this layer within the specimen. Due to the holistic consideration of stresses and deformations within the reinforced soil and the determination of the relationship between stresses, strains and reinforcement activation the results presented in this thesis constitute a further step towards understanding and describing the mechanical behaviour of the composite material geogrid reinforced soil.

Within the scope of this work two aspects of zinc oxide front contact layers in silicon thin film solar cells were investigated: The application of low-cost and industrial relevant production processes and the quality evaluation and control of the front contact surface texture. The surface texture influences the solar cell efficiency as it plays a key role in the solar cell’s light management. To investigate the application of low-cost processes and materials, zinc oxide front contacts were deposited with an industrial relevant, high-rate deposition process on commercially available float glass. In a first step, a silicon oxynitride (SiOxNy) interlayer was developed and deposited on the float glass substrates. This interlayer was characterized regarding three layer properties: anti-reflective properties, nucleation properties for zinc oxide growth and barrier properties to prevent sodium diffusion from the glass substrate. On top of the interlayer aluminum-doped zinc oxide was sputtered with a high-rate deposition process using two ceramic 0,5 wt % rotatable magnetron targets. A suitable pressure and temperature regime for the deposition process was defined. Different surface textures and their influence on the light-management of a-Si:H/µc-Si:H tandem solar cells was investigated. The work focused on the two optical effects: light-coupling and light-scattering. Small front contact structures with a diameter of about 400 nm were suitable for light-coupling as long as they provided a significant roughness around 100 nm at the same time. Larger features in the range of ca. 700-900 nm were more suitable for light scattering within the device given that they also provided a high roughness. A model using the lateral structure diameter and the roughness of the front contact surface texture as parameter to describe the ability of a surface texture to couple and scatter light was presented. An optimized double-texture that combined a surface texture for light scattering (primary texture) and a superimposing surface texture for light-coupling (secondary texture) showed a significant improvement of the light-trapping compared to the single texture substrate in tandem solar cells. The initial efficiency of the a-Si:H/µc-Si:H tandem soalr cell on a double-textured front contact was as high as 12,5 % with a total absorber layer thickness of only 1,64 µm. Angular resolved scattering measurements are known to be highly texture sensitive and were performed to evaluate the surface texture quality. A correlation between the discrete large angle scattering at the front contact layer and the short-circuit current density of µc-Si:H solar cells as well as a-Si:H solar cells was demonstrated. The above mentioned surface quality parameters (lateral structure diameter and roughness) of front contacts in tandem solar cells were extracted from angular resolved scattering measurements. A correlation between the ratio of the intensities measured in transmission at the discrete angles 15° and 60° and the lateral structure diameter was shown. Additionally, a correlation between the surface texture roughness and the integral of all scattered light was demonstrated. To extend the monitoring to a control of the surface texture quality, selected parameters in the zinc oxide production process were evaluated related to their correlations with the surface texture quality parameters. Especially the deposition temperature showed a strong influence on the lateral structure diameter of the texture. A linear functional relationship between the temperature and structure diameter was demonstrated for the first time within the temperature range that was suitable for the front contact deposition. The lateral structure diameter was determined using angular resolved scattering measurements after the surface texturing step. Applying a feedback loop the angular resolved scattering data was successfully used in a test series to adjust the deposition temperature of a new sputter deposition system to yield the angular resolved scattering data and hence surface topography of a reference texture.

A severe accident in a nuclear power plant (NPP) can lead to core damage in conjunction with the release of large amounts of hydrogen. As hydrogen mitigation measure, passive autocatalytic recombiners (PARs) are used in today’s pressurized water reactors. PARs recombine hydrogen and oxygen contained in the air to steam. The heat from this exothermic reaction causes the catalyst and its surroundings to heat up. If parts of the PAR heat up above the ignition temperature of the gas mixture, a spontaneous deflagration or detonation can occur. The aim of this work is the prevention of such high temperatures by means of passive cooling of the catalyst with heat pipes. Heat pipes are completely passive heat exchanger with a very high effective thermal conductivity. For a deeper understanding of the reaction kinetics at lower temperatures, single catalytic coated heat pipes are studied in a flow reactor. The development of a modular small-scale PAR model is then based on a test series with cooled catalyst sheets. Finally, the PAR model is tested inside a pressure vessel under boundary conditions similar to a real NPP. The experiments show, that the temperatures of the cooled catalytic sheets stay significantly below the temperature of the uncooled sheets and below the ignition temperature of the gas mixture under any set boundary conditions, although no significant reduction of the conversion efficiency can be observed. As a last point, a mathematical model of the reaction kinetics of the recombinaton process as well as a model of the fluid dynamic and thermohydraulic processes in a heat pipe are developed with the data obtained from the experiments.

It is an undeniable fact that the number of chloride induced corrosion damages in reinforced concrete structures has increased considerably during the last decades. In the context of actual scientific efforts regarding the modelling of chloride induced corrosion phenomena of steel in concrete this thesis aims at the analysis of the time dependent behaviour of electro-chemical and morphological parameters of the macro-cell anode being the location of active metal dissolution. As a result of electro-chemical investigations time dependent and statistically firm free corrosion potentials and specific polarisation resistances of the macro cell anode are now available for the modelling of chloride induced corrosion phenomena of steel in concrete with high water and chloride contents. Further investigations into the current-potential-relation of macro cell anodes show a fairly linear devolution up to anodic overpotentials of 140 mV. This information leads to less time consuming calculation procedures in the numerical analyses of chloride induced corrosion phenomena. The combined evaluation of electro-chemical and gravimetric test series shows that the proportion of self corrosion activity can be as high as 50% of the overall corrosion activity. The results confirm that it is absolutely necessary to take self corrosion into account in any future corrosion modelling. Surface analyses by means of a cutting edge 3-D surface scanner shows, that it is possible to quantify the development of depassivated surface areas and maximum pitting depths with high accuracy. Using regression analyses simple mathematical expressions can be derived describing the time dependent behaviour of the surface morphology as a result of ongoing chloride induced corrosion processes. Based on these results a new calculation model is established describing the corrosion related loss of steel volume by means of a modified formula for a cone volume. This formula is based on parameters which can be obtained by onsite inspections of reinforced concrete structures. Furthermore investigations into the minimal residual cross section leads to the development of a time dependent factor which enables the engineer to transform corrosion induced volume losses (e.g. obtained from calculations, morphological or gravimetric investigations) into minimum cross sections of the respective rebar. This factor, for the first time, is based on a significant scientific data base regarding the minimum cross section of corroding steel in concrete with high water and chloride contents.

Ein neuartiges Online-Verfahren zur Detektion und Identifizierung von fehlerbehafteten Messdaten am Motorenprüfstand wurde mittels multivarianten statistischen Verfahren entwickelt, implementiert und erfolgreich in Testreihen angewandt. Das Verfahren beinhaltet die Online-Erfassung der Messdaten und die Überprüfung durch physikalische Kriterien bzw. Regressionsanalysen, um mögliche Auffälligkeiten herauszufiltern. Aussagen über die Messdatenqualität werden anhand eines leicht verständlichen und auf Fuzzy-Logik basierenden Ampelsystems getroffen. Das entwickelte Verfahren vermindert den Anteil an ungültigen Messungen und spart damit erheblichen Zeit- und Personalaufwand ein. Die Rentabilität von Motorenprüfständen wird signifikant gesteigert. A novel online procedure for the detection and identification of invalid data measured on an engine test bench was developed by using multivariate analysis. The procedure was implemented and successful applied in test series. The procedure includes the online acquisition of the data and their verification by means of physical laws and regression analysis to filter possible abnormalities. An easy to understand traffic lights system was developed by using the fuzzy logic theory in order to judge the quality of the measured data. The developed procedure reduces the rate of invalid measurements and saves considerable time and personnel costs. Thus the profitability of the engine test benches is increased significantly.

The dimensioning of road infrastructures has taken place in Germany since 2001 according to the Manual for the Design of Road Infrastructures (HBS) which is modeled after the American Highway Capacity Manual (HCM). Since that time the description of traffic quality in the German technical rules has been based on the principle of level of service (LOS). The traffic quality defined solely according to capacity in the technical rules up until then has undergone a theoretical supplement in its basic principles due to the idea of a user-oriented viewpoint, which means the driver’s point of view. The existing methods for evaluating the design parameters however still show, nine years after being introduced, some weaknesses and gaps, particularly with regard to the driver’s point of view. For example with the current HBS partial elements of intersections, individual stretches of road etc. can only be designed in terms of traffic engineering. Intersections as a whole (all directions and all lanes together) and seen from the driver’s point of view cannot be evaluated at present with the HBS. So together with this dissertation a method was developed for the overall evaluation of a traffic light controlled rural road intersection which contains both a traffic-related and a user-oriented component. The newly developed method is based on a basic analysis which in addition to the description of the fundamental requirements and criteria for the design and evaluation of traffic light installations also considers psychological basic ideas with regard to modeling the circulation of traffic on the human-system level. Of particular significance in this context are the perception and interpretation of traffic situations and the emotions and reactions of the drivers which contribute to the general traffic climate. Subsequently the newly developed method is based on the existing parameters of Chapter 6 of the HBS “Intersections with traffic light installations” and supplements the current quality grade concept for evaluating the individual signal groups of a traffic light installation with a collated, user-oriented evaluation of the whole intersection. Due to the different facets a link was created for this purpose between traffic engineering, sociological and psychological findings which were gained from test series in the traffic laboratory and from real life. For the method evaluation curves to determine dissatisfied drivers and an acceptance rating to establish the tolerance of waiting times were derived through empirical studies and analysed by means of sensibility tests. The evaluation curves were able to show how negative influences on the traffic climate occur when the waiting times at an intersection increase. After only 60 seconds of waiting time over 50% of the drivers are impatient and over 15% even greatly annoyed. With these values the acceptance limit which could be found to range between 60 and 70 seconds at a red traffic light is almost reached. The road categories, the time gaps of the intersecting traffic flow and the position of the intersection in the course of a drive aren’t the decisive parameters for the arising negative emotions, but probably the psychological parameters of the driver himself. In consideration of these findings the method is used to calculate a dissatisfaction index and a user-oriented traffic quality mark for a standard intersection with one or two lanes at the access road. On the basis of the waiting times which occur and the resulting ratings it is possible to make a statement on the level of dissatisfaction of the drivers crossing the intersection. This method for rating user-oriented traffic quality is at present the only method that can evaluate a traffic-light controlled intersection on a rural road from the point of view of the user. This also ultimately enables a more appropriate discussion on the required minimum level of service and at the same a heightened consideration of the quality aspects from the point of view of the road user.

The present work investigates the fuel specific influences on the operation of a burner system. The examinations focus on fuel aging and its influence upon failsafe operation of burner components. Aging mechanisms of conventional mineral oils as well as blends containing bio components are investigated by experiments. FAME (Fatty Acid Methyl Ester) was used as trace content of 0,25% (v/v) up to 0,5% in IGO (Industrial Gasoil) as well as a blend component (5% and 20%). A testing apparatus and an according testing method were developed for the application technological investigation of the fuels. The measured fuel characteristics were used for benchmarking of the tested fuels. The aging of the tested fuels during the test run was surveyed by periodically applied fuel analytics. A better knowledge of the causes of failures and the aging mechanisms was achieved by analysis of the deposits that formed upon and inside test rig components. The following test series enabled the quantification of the influence of oil tube material, additive-based fuel stabilization and filter pore size. Objective of the survey was the quantification and/or the qualification of potential influences that led to component failure. Characteristics used for theoretical consideration of the reaction kinetics of oxidation were determined by the analytical measurements. A forecast model of the fuel aging was derived using the test rig. This forecast model enables a prognosis of the aging behavior for changed parameters such as barrel temperature or fuel volume. In order to gain a complex understanding of all coherences related to malfunctions a systematical analysis of the influences of all involved components in the burner was conducted in a torque test rig. The characteristics of different mechanical components such as motor, blower and pump were measured accordingly.

Textile reinforced concrete is a composite building material consisting of a fine-grained concrete and a textile reinforcement predominantly made of AR-glassfibers or carbonfibers. As a result of its material characteristics the textile reinforcement combines the advantages of corrosion resistance and an effective and economic positioning in the cross-section of the structural component. The precondition for the success of textile reinforced concrete is the availability of design models and construction rules, which enable the production of durable and sustainable elements. The intention of this thesis is the development of models, which enable the realistic mechanical description of the load-bearing behaviour of textile reinforced concrete components under tension, bending and shear loading. For this purpose experimental and theoretical investigations are presented in which the effects of significant parameters of the material characteristics and the loading situations are surveyed. This work contributes to the development of a consistent design concept for textile reinforced concrete components within the Collaborative Research Centre 532, which has been installed at the RWTH Aachen University by the German Research Foundation (DFG) in 1999.The dissertation starts with a general survey of the characteristics of the material components of textile reinforced concrete and a summary of existing design models. The influences of the reinforcements’ characteristics, reinforcement direction, cyclic loading and biaxial loading on the load-bearing behaviour were examined in systematic experimental investigations and are described in this work. The analysis of the tensile load bearing behaviour includes numerical simulations with the Two-Subroving-Model and the check of the adaptability of analytical models. The results are the basis of an own analytical model for the description of the tensile load-bearing behaviour of textile reinforced concrete components with different reinforcement properties. The bending and shear capacity were tested on beams. Within these test series, significant parameters as e.g. the characteristics and the amount of the textile reinforcement as well as additional normal loading and the shear slenderness were considered and their effect was identified.The results of the investigations were used for the development of models for the calculation of the tensile strength, bending and shear capacity of textile reinforced components. The models describe the average load-bearing behaviour with good accuracy. The applicability is demonstrated by prototypical realizations of textile reinforced concrete façade elements, a rhombic lattice girder and a hollow core slab element.

The use of sandwich materials can lead to economical advantages in many applications by means of weight reduction. In spite of its large demand, its distribution in the field of mechanical engineering is constrained due to unsolved problems in the connection technology and uncertainties in the mechanics of such structures. Hence, in this filed, there exists a demand for the support of design engineers in designing of sandwich structures. Today, the Finite-element-method (FEM) for the simulation of the mechanical behaviours of complex structures is well established at the CAD-workstation; however the particularities of composite materials require advanced modelling- and analysis strategies. This work shall give the design engineer hints, with which a suitable FEM-system can be chosen for appropriate modelling of the loading cases and for evaluating the calculated results. To achieve this, simulations were carried out with different FEM-systems, whose results are validated by experiments. In the framework of this thesis, only plate materials with steel face and a PUR foam core that is very common in the mechanical engineering applications are considered. The simulated loading case is the four-point-bending-test according to DIN 53293, which is established as a test procedure and creates a practice relevant stress condition. After describing the possible approaches for FE-Modelling of the loading case, results of the simulation of a 3D-CAD/FEM-Integration with the FEM-Systems ANSYS, ABAQUS and ALGOR and their corresponding working steps are presented. Here the sandwich plate was created either completely through volume elements or through volume elements and shell/plate elements. In the experimental part of the work, the simulated loading case was experimentally repeated on the servo-hydraulic test machine as test series, whereby the linear elastic behaviour and the different failure of sandwich plate were investigated. The results obtained with aid of the FEM were compared to the analytical and experimental results. It shows that the computed stress values have a very good agreement with the analytical results and experiments. In terms of accuracy of the calculated results, ANSYS seems to be the most suitable one; however ALGOR has the best characteristics with regard to the usability. In each case, it has been proved that the described modelling strategies can be achieved with a reasonable effort and it delivers useful results to understand the deformation behaviour of sandwich structures. Also for the observation of different failure modes of the sandwich plate, the linear elastic FEM-Simulation seems to be a suitable tool. The face wrinkling at the places of the load transmission is investigated with the help of experiments. It is determined that, with the results of the FEM-calculation, the appearance of this special, partially unstable phenomenon can be predicted and explained. Additionally a core shear failure could also be investigated by a modification of this experiment, which could also be predicted with the help of FEM-simulation.

In industry the employment of fluid and gaseous goods is widely spread. Besides standing cylindrical fluid tanks for gaseous materials saddle supported cylindrical tanks are used for the transport of goods in general. The storage and the transport of dangerous goods represent an enormous risk potential for humans and environment. To minimize this risk the legislator makes numerous demands on the operation and the technical design of such tanks. In particular the knowledge of the carrying behaviour for all foreseen arising loads is important for the technical design. These are beside loads from operating pressure and vertical load also horizontal loads. Thus the "Verordnung über die innerstaatliche und grenzüberschreitende Beförderung gefährlicher Güter auf der Straße und mit Eisenbahnen", briefly GGVSE, with reference to "Anlagen A and B des Europäischen vom 30.September 1957 über die internationale Beförderung gefährlicher Güter auf der Straße", briefly ADR, demands the separate proof of stability for tanks under a horizontal transverse force amounting to the gravityload. Whereas for the vertical load case both static and dynamic investigations lead to the today valid practical design aids and calculation formulas published in the "AD-Merkblätter" and the "British standard 5500", such investigations and design aids are not present for the case of the horizontal transverse load. This dissertation helps to eliminate this deficit and thus to enable a final estimation of the carrying behaviour under consideration of the static and dynamic horizontal transverse load. The development of calculation formulas and design aids should help to estimate the carrying behaviour. Therefore the dissertation is arranged into two parts; a first part, which deals with the stress in the shell under the dynamic horizontal transverse load and a second part, which deals with static calculation and takes the results of the dynamic research into account. In the first part dynamic experiments on a saddle supported cylindrical tank are made. Therefore the tank is stored on two concrete saddles. The saddles are fixed with a sub-construction of doublesymmetrical steel girders. This construction is oscillated in transverse direction. The charge of the tank (charge: water), the distance to the head stiffeners to the saddles and the frequencies are varied. In each experiment the circumferential and logitudinal strains, the accelerations and the contact pressure distribution between the shell and the saddle are measured. The results of the test series serve as reference for a finite element modelling. In this finite element model (fem) the load distribution on the cylindrical wall due to the dynamic horizontal load is of substantial interest. The comparison of the stresses measured in the experiment with the computation results based on a timedepent load distribution, serves as acknowledgement of the chosen load distribution. This load distribution is the basis for static calculation in the second part of the work. The second part of the work has the intention of developing practice-oriented calculation formulas which enables the engineer already in the pre-dimensioning stage of saddle supported tanks to take the horizontal transverse load, like demanded in the ADR, into account. In addition two different computation methods are analyzed with regard to their suitability for a parameter study of the analyzed system. These are on the one hand the computation with the help of the finite elements method (fem) and on the other hand the computation on basis of an analytic computation method, which is self-depent developed further for the analyzed case. The analytic method is based on the generalised technical bending theory. Both the fem and the analytic method lead to the result that the peak stress at the saddle horn rapidly reaches the theoretical yield stress. Before making the parameter study to develop practice-oriented calculation formulas some calculation based on an elastic-plastic material behaviour are made. Therefore the van Mises’ equivalent stress criterion model is used. A parameter study follows in which the radius, the shell thickness, the contact angle between the saddle and shell, the length, the distance of the head stiffener to the saddle and the saddle rigidity are varied. The evaluation of the computation results supplies calculation formulas suitable for the hand calculation under consideration of the elastic-plastic carrying behaviour in the pre-dimensioning stage of saddle-supported cylindrical shells under horizontal transverse load. This enables the planning engineer in the future to consider the horizontal transverse load appropriately even in the pre-dimensioning stage. The research of practice-oriented questions regarding the magnitude of transverse accelerations affecting the tank, the constructional design of the saddles and the ratio of the maximum stress due to vertical load to the stress due to horizontal load finally completes the dissertation.

Im Rahmen der vorliegenden Arbeit wurde ein Meßprinzip zur Erfassung der geometrische Parameter von Anschlüssen mehrpoliger SMT-Bauelemente entwickelt, umgesetzt und charakterisiert. Die Simulation der realisierten Abbildung und die Erarbeitung von Auswertungsstrategien zur Extraktion der gewünschten Parameter aus den aufgenommenen Datensätzen stellten weitere Arbeitspunkte dar. Untersuchungen an Realbauteilen und Teststrukturen dienten zur Verifikation von Meßprinzip und Auswertungsalgorithmen. Die hier erstmals vorgestellte neue Anordnung von CCD-Zeilenkamera zu Bauelement (nichtfrontale Beobachtung) bringt den Vorteil, daß nur zweidimensionale Bilder ausgewertet werden müssen, die aber ansatzweise Informationen über die dritte Dimension enthalten. Die Verwendung einer Zeilenkamera erfordert zwar den Einsatz eines Linearverschiebetisches, der das zu vermessende Bauteil vor der Kamera vorbeifährt, bringt aber den großen Vorteil, daß die Auflösung des resultiemden Zeilenscans lediglich in vertikaler Richtung (entlang der CCDZeile) beschränkt, lateral (entlang der Linearbewegung) aber in weiten Bereichen frei variierbar ist. Mit den hier eingesetzten Komponenten konnten eine vertikale Auflösung von ca. 1, und eine laterale Bildauflösung von ca. 3,5 mikrometer pro Pixel, erreicht werden. Die laterale Meßauflösung (Bildauflösung unter Berücksichtigung der Positioniergenauigkeit des Lineartisches) lag bei etwa 6,4 Mikrometer pro Pixel. Die Auswertungsstrategie umfaßt zwei Schritte: 1. Untersuchung der Periodizität der aufgenommenen Anschlußreihe 2. Bestimmung der geometrischen Parameter eines einzelnen (fehlpositionierten) Anschlusses Der erste Schritt wird mit Hilfe der Wavelet-Zerlegung realisiert, was auf diesem Gebiet als Novum zu betrachten ist. Für den zweiten Schritt werden die sechs signifikanten Kanten des zu untersuchenden Einzelanschlusses berechnet. Die Lage der Kanten zueinander liefert dann beispielsweise die Lead-Breite oder die Lead-Höhe. Anhand der Kantensteigung kann auf eine eventuelle Verkippung der Anschlüsse rückgeschlossen werden. Im praktischen Teil der Arbeit wurde zunächst die Wiederholbarkeit der Messungen nach DIN1319 Teil 3 [128] bestimmt. Sie liegt in lateraler Richtung innerhalb der berechneten Meßauflösung, in vertikaler Richtung leicht darüber. Die Versuche zur Verifikation des Meßprinzips umfassen eine Vorversuchsreihe und eine Meßreihe mit Realbauteilen. Desweiteren wurden Teststrukturen mit einem Pitch von 300/im in zwei Meßreihen vermessen. Die Auswertung ergab eine sichere Detektion von Fehlerstellen bereits nach der Wavelet-Analyse. Die Untersuchung einzelner Anschlüsse (1000 Leads von Realbauteilen und 160 Leads von Teststrukturen) erbrachte in einigen Fällen Aussagen zur Genauigkeit der verwendeten Werkzeuge und Masken. Einzelne Lead-Reihen wurden zusätzlich mit einem Meßmikroskop oder einem Kohärenzradar [71] vermessen. Diese Vergleichsmessungen bestätigten die sehr gute Übereinstimmung der mit dem hier vorgestellten Meßsystem vermessenen Lead-Reihen mit der Realität. Zusammenfassend läßt sich sagen, daß mit dem hier beschriebenen Meßprinzip und der dazugehörigen Auswertungsstrategie ein Meßwerkzeug geschaffen wurde, welches eine flexible, automatisierte und hochgenaue Vermessung von Anschlußreihen mehrpoliger SMT-Bauelemente ermöglicht. Wegen der relativ großen Meßdauer eignet sich das realisierte Meßsystem sicherlich nicht für den Einsatz in der Massenfertigung elektronischer Schaltgruppen, wohl aber für die Auswertung von Stichproben zur Charakterisierung verwendeter Werkzeugfolgen bei der Lead-Frame-Fertigung und als begleitendes Meßverfahren für Fügeprozesse, die sehr enge Fertigungstoleranzen erfordern. Für eine Weiterentwicklung des Meßprinzips exisitieren viele Ansatzpunkte. Vordringlichstes Ziel muß es sein, die Meßdauer herabzusetzen. Dies geschieht zum einen passiv mit der Entwicklung von immer leistungsfähigeren Prozessoren, zum anderen aber kann auch aktiv mit dem Einsatz einer Zeilenkamera, die eine höhere Bildwiederholungsfrequenz aufweist, die Meßdauer sehr stark reduziert werden. Die hier eingesetzte Kamera hat eine Bildwiederholungsfrequenz von 60Hz, Stand der Technik sind bereits Frequenzen von mehreren kHz. Durch schnellere Zeilenfolgen kann aber auch gleichzeitig die laterale Bildauflösung verbessert werden. Dadurch werden die Werte für die Meßauflösung und sicherlich auch für die Wiederholbarkeit noch weiter verbessert. Weiterer Entwicklungsbedarf ergibt sich auch bezüglich der Konstruktion der Bauelementhalterung und bei der Auswahl des Linearverschiebetisches. Letzterer muß eine sehr gute Positioniergenauigkeit aufweisen. Eine Möglichkeit der Integration des neu eingeführten Meßprinzips in eine Anlage zum Laserstrahl- Mikroschweißen von SMT-Bauelementen wird im folgenden kurz vorgestellt. Die Entwicklung [4] umfaßt die Konzeption und Konstruktion eines Nd: YAG-Laserschweißkopfes zum Fügen von Gull Wing-SMDs. Dieser Bearbeitungskopf dient gleichzeitig als Bestückkopf, d.h. er greift das Bauelement, setzt es auf die Leiterplatte und fügt es anschließend punktuell. Das Meßsystem zur Leadgeometrieerfassung kann innerhalb dieses Konzeptes modular zwischen „Greifen” und „Bestücken” des Bauelements geschaltet werden. Nach diesem Meßschritt können die, aufgrund der Bauelementgeometrie vorgegebene, Fokuslage (lateral und vertikal) korrigiert und die Energie des Laserpulses dem Volumen des Lead-Fußes angepaßt werden., In the context of the present work, a measuring principle for the acquisition of the geometric parameters of connections of multi-pole SMT components was developed, implemented and characterized. The simulation of the realized image and the development of evaluation strategies for extracting the desired parameters from the recorded data sets represented further working points. Examinations on real components and test structures served to verify the measuring principle and evaluation algorithms. The new arrangement of CCD line camera to component (non-frontal observation) presented here for the first time has the advantage that only two-dimensional images need to be evaluated, but which contain some information about the third dimension. The use of a line scan camera requires the use of a linear displacement table, which moves the component to be measured in front of the camera, but has the great advantage that the resolution of the resulting line scan is limited only in the vertical direction (along the CCD line), laterally (along the Linear movement) but can be freely varied over a wide range. With the components used here, a vertical resolution of approx. 1 and a lateral image resolution of approx. 3.5 µm / pixel could be achieved. The lateral measurement resolution (image resolution taking into account the positioning accuracy of the linear table) was around 6.4 µm / pixel. The evaluation strategy comprises two steps: 1. Examination of the periodicity of the recorded row of connections 2. Determination of the geometrical parameters of a single (incorrectly positioned) connection The first step is implemented with the help of wavelet decomposition, which is a novelty in this area. For the second step, the six significant edges of the individual connection to be examined are calculated. The position of the edges relative to one another then provides, for example, the lead width or the lead height. Based on the edge slope, it can be concluded that the connections may be tilted. In the practical part of the work, the repeatability of the measurements was first determined in accordance with DIN1319 Part 3 [128]. It lies within the calculated measurement resolution in the lateral direction and slightly above it in the vertical direction. The tests for verifying the measuring principle include a preliminary test series and a series of measurements with real components. Furthermore, test structures with a pitch of 300µm were measured in two series of measurements. The evaluation showed a reliable detection of defects already after the wavelet analysis. The examination of individual connections (1000 leads of real components and 160 leads of test structures) yielded statements about the accuracy of the tools and masks used in some cases. Individual rows of leads were also measured with a measuring microscope or a coherence radar [71]. These comparative measurements confirmed the very good agreement of the lead series measured with the measuring system presented here with the reality. In summary, the measuring principle described here and the associated evaluation strategy created a measuring tool that enables flexible, automated and highly precise measurement of connection rows of multi-pole SMT components. Because of the relatively long measurement duration, the implemented measurement system is certainly not suitable for use in the mass production of electronic switching groups, but it is certainly suitable for evaluating random samples to characterize the tool sequences used in lead frame production and as an accompanying measurement method for joining processes that have very tight manufacturing tolerances require. There are many starting points for a further development of the measuring principle. The primary goal must be to reduce the measuring time. On the one hand, this happens passively with the development of increasingly powerful processors; on the other hand, the measurement time can also be reduced very actively by using a line scan camera that has a higher refresh rate. The camera used here has a refresh rate of 60Hz, the prior art already has frequencies of several kHz. The faster image sequences can also improve the lateral image resolution at the same time. This further improves the values for the measurement resolution and certainly also for the repeatability. Further development requirements also arise with regard to the construction of the component holder and the selection of the linear displacement table. The latter must have very good positioning accuracy. One possibility of integrating the newly introduced measuring principle into a system for laser beam micro welding of SMT components is briefly presented below. The development [4] includes the conception and construction of an Nd: YAG laser welding head for joining Gull Wing SMDs. This processing head also serves as a placement head, i.e. he grabs the component, places it on the circuit board and then adds it selectively. Within this concept, the measuring system for recording lead geometry can be switched modularly between “gripping” and “fitting” the component. After this measurement step, the focus position (lateral and vertical), which is predetermined based on the component geometry, can be corrected and the energy of the laser pulse can be adapted to the volume of the lead foot., Fertigungstechnik - Erlangen, 99