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This paper and its second part introduce a new formability test based on double-action radial extrusion to characterize material formability in the bulk-to-sheet material flow transitions that are commonly found in metal forming. This first part draws from the presentation of a multidirectional tool, which was designed to convert the vertical press stroke into horizontal movement of the extrusion punches towards each other, to aspects of experimental strain determination, fractography and finite element analysis. The methodology and tooling that are introduced here pave the way for subsequent testing and modelling of the different modes of fracture in three-dimensional to plane-stress evolutions, typical of bulk-to-sheet material flow transitions, by means of the new proposed test.

This second part of the paper is focused on double-action radial extrusion testing and modelling to characterize material formability and failure in the bulk-to-sheet material flow transitions that are commonly found in metal forming. Results show that three-dimensional to plane-stress evolutions at the radially extruded flanges lead to different modes of fracture (by tension and by shear) that may or may not be preceded by necking. The use of double-action radial extrusion as a formability test also reveals adequate to characterize the failure limits of very ductile metallic materials, which cannot be easily determined by conventional upset compression tests, and to facilitate the identification of the instant of cracking and of the corresponding fracture strains by combination of the force vs. time evolutions with the in-plane strains obtained from digital image correlation.

The iterative development process of forming tools is cost- and labor-intensive. The main reason for this is the high complexity of interaction between forming machine, tool structure, and process, which is currently only partially taken into account in simulations and during tool tryout. By digitizing the tool development process, it is possible to save iteration loops during the design phase before tool production and during rework in the adjustment phase. In this article, a novel approach for the consideration of the elastic properties of the clamping surfaces of the forming machine within the forming simulation is presented. A case study on the virtualization of pressure distribution (PD) during the die spotting process and the derivation of recommended actions for the rework based on virtual PDs was conducted. The results demonstrate the potential for saving time, cost, and labor during the tryout process in sheet metal forming.

The manufacturing of three-dimensional components by deep drawing is performed using flat sheets. The material properties of the sheets are influenced by the deep drawing process by means of microstructural effects (e.g., anisotropy, residual stresses, voids, lattice defects). The resulting effects, especially voids and lattice defects, influence the component in the form of damage accumulation and evolution. Depending on the process route and parameters, different load paths are created, which lead to different damage evolution scenarios. This paper numerically investigated the influence of process parameter (drawing ring radius) as well as process set-up (multi-step deep drawing and reverse drawing) during deep drawing and the associated load paths on damage evolution in rectangular cups made out dual phase steel DP800.

Made available in DSpace on 2021-06-25T10:25:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Accumulative roll bonding is a severe plastic-forming process proposed to manufacture ceramic particle-reinforced multilayered metal matrix composites. In this work, low-cost composite multilayered laminate was produced by roll bonding commercially pure aluminum 1100 with 5% in volume of reinforcing microscale silicon carbide particles. Microstructural features, hardness, tensile properties in the presence of stress concentrators, and wear resistance were assessed. Fracture surface inspection was carried out to determine operating failure mechanisms. Hardness was significantly enhanced, whereas tensile properties only moderately improved by ceramic particles incorporation. The main reasons were some degree of recrystallization, work-hardening relief due to periodic annealing, minimum grain refinement, and somewhat agglomerated carbide particles. Though tensile properties increments were not much attractive, exceptional increase in wear performance was achieved due to the addition of particulate carbon-rich ceramic phase, which acted as solid lubricant mitigating abrasion, adhesion, and delamination wear mechanisms. The manufactured composite laminate can be worthwhile in applications where low cost, notch insensitivity, and superior wear and weather resistances are design requirements, as outdoor decks and patios. Department of Materials Engineering University of Sao Paulo (USP), Av. Joao Dagnone 1100, Jd. Sta Angelina Institute of Engineering Science and Technology (IECT) Federal University of Vales do Jequitinhonha e Mucuri (UFVJM) Institute of Materials Research German Aerospace Centre Metallic Structures and Materials Systems for Aerospace Engineering RWTH Aachen University Sao Paulo State University (UNESP), Campus of Sao Joao da Boa Vista, Av. Prof. Isette Correa Fontao, 505, Jardim das Flores Sao Paulo State University (UNESP), Campus of Sao Joao da Boa Vista, Av. Prof. Isette Correa Fontao, 505, Jardim das Flores

Pre-painted sheet metal (e.g. coil coated with polyester-melamine) undergoes large deformations when formed into architectural cladding or white goods. The coatings provide protection and superior aesthetics, so must withstand failure by cracking or delamination during forming. The T-bend test is an industry standard test used to qualitatively compare the formability of coatings and mimics the conditions experienced during hemming processes. The failure of coatings during forming is strain governed, so understanding the surface strains in the T-bend test is of great interest to manufacturers. For the first time, the maximum surface strains experienced during the T-bend test have been predicted using finite element modelling (FEM) and verified experimentally using digital image correlation. The experimental shapes of the deformed blank are compared with the FEM results for further verification. In addition, a novel analytical model is proposed to determine the maximum surface strains. It is shown that strains of up to ~ 225% are applied during a 0T test (bent around a zero thickness spacer) reducing to ~ 23% at 4T (bent around a four times sheet thickness spacer). The finite element model, experimental data and new analytical model show excellent agreement and indicate that behaviour is independent of the substrate thickness or material used. Understanding the strain behaviour quantifies the formerly qualitative T-bend. This will improve the efficacy of the test, allowing metal formers and coating developers to better understand the performance requirements, to reduce waste and to develop better coatings. Graphical abstract

In the last few decades, metal-based composites and related manufacturing methods have attained a significant research attention thanks to the possibilities they offer to tailor both the material properties and the part in-service performances. A variety of metal-based composite parts is available for commercial applications since more affordable and robust manufacturing processes and quality control techniques have recently overcome many challenging technological issues. The paper aims at describing the forming processes applied to metal-based composites, with particular emphasis on the process features, part obtainable characteristics, and modelling issues for a convincing design and optimization of the process itself. The most recent progresses and challenges are illustrated in detail, including innovative materials and processes that are emerging to answer the requirements of advanced engineering applications as well as new modelling techniques and current approaches to face economic and environmental issues.

Using foam as a carrier fluid in papermaking gives interesting new opportunities. Foam as a more viscous fluid than water is expected to behave differently in a dynamic process. This study presents results obtained under dynamic forming conditions in a semi-pilot scale research environment. Effects of process configurations and running conditions on increased forming speed, web properties, and difference between water-laid and foam-laid processes are shown. The studies were carried out using a water-laid former and the same environment modified for foam forming. In order to achieve increased forming speed, the open headbox was replaced with a closed headbox, and the former geometry was updated. The process foam was boosted with an additional foam pulper. The foam pulper was used as a machine chest for improving the dispersion of fibers into the foam. A much broader tensile strength ratio range (~3 to 8) was achieved with foam forming than with water-laid forming. Foam-laid paper had a broader pore size distribution and higher mean pore size. Formation and the formation spectra of foam-laid sheets were more uniform, leading to improvements in the properties of the fiber network.

In this study, four representative finite element (FE) based modelling techniques and an analytical solution for the prediction of 2D woven fabrics’ deformation during forming are compared back-to-back. Ordered from high to low fidelity they are: 1/a Multi-Filament (MF) method that sits between micro- and meso-scale that uses multiple beam element chains to represent each fibre yarn; 2/a meso-scale 3D representation (3D-Shell method) that uses 2D structural shell elements to model each fibre yarn; 3/a 2D continuum element approach that uses coincident membrane and shell elements with user defined material properties to capture the deformation response of textiles in an homogenised sense at the macro-scale; 4/pin-jointed net (PJN) models where the reinforcement directions are represented by extendable 1D elements, pin-jointed at the elements’ crossover points. These modelling approaches are systematically compared for identical forming processes with identical process and material parameters such as boundary conditions, weave architecture and tooling geometries. For completeness and to highlight the importance of considering inter-yarn and preform-to-tool interactions, a kinematic drape algorithm (based on geometrical mapping) is also considered. An attempt is made to visualise the overall modelling performance and computational cost of all representative modelling approaches by simplified metrics.

The increased production rate targets of the aerospace industry has driven the development of dry fibre processes and biaxial Non-Crimp Fabrics (NCFs). Understanding the forming behaviour of NCFs at scale is key to achieving high quality parts at high rates. The bias extension test is commonly used to characterise the shear behaviour of dry fabrics, for example as input to drape forming models. In industry, it is still often used as a standalone material selection tool as part of initial material selection processes. It is however well known that the boundary conditions of this test are often not representative of full-scale forming trials. A direct comparison with wrinkles observed during a forming experiment is carried out to show that the bias extension test overpredicts wrinkle height. Overall, the bias extension is considered unsuitable on its own for predicting preform quality in an NCF forming process where excess length is generated due to part geometry. If the bias extension is to be used as an NCF material ranking tool, wrinkle height data should be captured alongside force shear data, as shown in this study.

The automotive industry has undergone significant advancements and changes over time, resulting in the use of more complex parts in modern vehicles. As a consequence, the parts used in the manufacturing process are subject to higher stress levels, which reduce their service life. To mitigate this issue, surface treatments can be applied to improve the mechanical properties of the tools. In this study, we examined the impact of surface treatments on reducing tool stress during a cold forming process. The process involved reducing the thickness of a sheet from 6 mm to 2.5 mm, which generated high stresses in the tooling. We used finite element stress calculations to analyze the process and found that by reducing the friction coefficient to 0.1, tool stresses can be reduced by 20%, leading to an increase in tool life. Moreover, the press force and tool wear were also reduced by 18%. To validate the theoretical calculations, we performed field tests in a real manufacturing process.

In the present work, the elevated-temperature deformation characteristics and microstructural evolution of a Ti-5V-5Mo-5Cr-4Al alloy in solution-treatment conditions were studied under a tensile load at temperatures in the range of 25 to 550 °C and strain rates between 0.001 and 0.1 s−1. The results obtained indicated that, essentially, dynamic recovery (DRV) was the dominant softening mechanism in the case of the regimes considered. An analysis based on transmission electron microscopy (TEM) and the assessment of the mechanical behavior of the solution-heat-treated Ti-5V-5Mo-5Cr-4Al alloy revealed that dynamic precipitation (DPN) only took place at a strain rate of 0.001 s−1 and at temperatures of 450 °C and 500 °C. Void coalescence occurred upon an increase in the deformation temperature and a decrease in the strain rate due to a higher rate of diffusion and the provision of sufficient time for growth, respectively. The results obtained in the present study pave the way for the robust processing of this novel β titanium alloy. Depending on the deformation parameters, the deformation characteristics can be governed by either DRV (at moderate temperatures) or DPN (at moderate temperatures and at low rates of deformation).

Показана проблема утворення та пошуку шляхів утилізації відходів очисних споруд та запропонована технологія їх термічного оброблення та використання як сировинний компонент при виготовленні стінових каменів. Як зв’язуюче запропоновано використовувати поліетилен низького тиску. The paper discusses a problem of formation and search of efficient ways to recycle wastes generated by waste treatment plants, a proposed technology for their heat treatment and utilization of waste as a raw material component for the production of masonry units. Highdensity polyethylene is used as a binder.

International audience; Important information can be obtained by simulating the deformation of composite reinforcements on a mesoscopic scale. The knowledge of the direction and density of the fibres in the deformed reinforcement affects the mechanical properties of the composite and the permeability of the textile reinforcement. The quality of the initial geometry of the finite element model is important for these mesoscopic analyses. The internal reinforcement geometries can be defined by some software. Nevertheless, these are based on certain simplifications that may have drawbacks. In this paper, finite element models are obtained from X-ray tomography. These finite element models are designed for all types of reinforcements and avoid problems of yarn interpenetration. A hyperelastic constitutive equation is used for the behaviour of the yarn made of fibre. The results obtained by the simulation for the compaction of a 3D reinforcement are compared with the experimental results with good consistency.

This paper presents a new joining by forming process to produce lap joints in metal-polymer sandwich composite sheets. The process involves drilling a blind hole in each sheet for removing the upper metal skin and the polymer core layer, and fixing them together by compressing a metal insert placed in-between to obtain a form-fit mechanical nugget. The cross-section of the joint resembles that of resistance spot welding, with the cold formed insert (‘nugget’) hidden inside the sheets. The geometry and size of the inserts are analysed by finite elements and experimentation to determine the effectiveness and performance of the new joints.

Flow forming is an incremental forming process frequently used in manufacturing axi-symmetric parts that require high mechanical properties and fatigue resistance for dynamic applications, such as automotive and aerospace, or large-size components whose deformation in one step would require excessive loads. Nevertheless, the process design still remains challenging since the strain and stress states of the locally-deformed material are not clearly understood. To fill this gap, the paper focuses on the numerical modelling of forward flow forming, when it is applied to freeform-section profiles. The reference process is the flow forming of an aluminium alloy automotive wheel carried out in hot conditions. Results in terms of strains and stresses applied to the material by the rollers are presented, showing that relevant hydrostatic pressure conditions may be general with beneficial effects on the material formability.

Este trabalho foi financiado pelo Concurso Anual para Projetos de Investigação, Desenvolvimento, Inovação e Criação Artística (IDI&CA) 2016 do Instituto Politécnico de Lisboa. Código de referência IPL/2016/CompSBJ_ISEL Submitted by Isabel Melo (imelo@sa.isel.pt) on 2019-07-29T09:59:38Z No. of bitstreams: 1 Experimental_MARLoja.pdf: 2048657 bytes, checksum: 5c5af5020ac2fe21c79ab3e66ecd0eb8 (MD5) Made available in DSpace on 2019-07-29T09:59:38Z (GMT). No. of bitstreams: 1 Experimental_MARLoja.pdf: 2048657 bytes, checksum: 5c5af5020ac2fe21c79ab3e66ecd0eb8 (MD5) Previous issue date: 2019-07 info:eu-repo/semantics/publishedVersion

Статья посвящена формированию профессионального самоопределения у учащихся старших классов сельских и городских школ. В ходе проведенного исследования было выявлено, что недостаточно изучена степень готовности учащихся к профессиональному самоопределению, не проанализированы пути и средства его формирования на основе дифференцированного подхода gс различными уровнями профессиональной готовности, не выявлены эффективные методы и способы педагогического управления процессом профессионального самоопределения школьников, учитывающие фактор влияния среды проживания (город или село). = At thе рrеsеnt timе, whеn thе рrоfiling оf еduсatiоn has bесоmе a rеlеvant and dеmandеd nесеssity, thе fundamеntal tasks оf рrоfеssiоnal sеlf-dеtеrminatiоn faсе thе sсhооlсhildrеn. Thе analysis оf thеоrеtiсal sоurсеs has shоwn that thе rеadinеss оf studеnts fоr рrоfеssiоnal sеlf-dеtеrminatiоn hasn't bееn suffiсiеntly studiеd, thе ways and mеans оf its fоrmatiоn оn thе basis оf a diffеrеntiatеd aррrоaсh tо studеnts with diffеrеnt lеvеls оf this rеadinеss havеn't bееn analyzеd, thе mоst еffесtivе mеthоds and mеthоds оf реdagоgiсal managеmеnt оf thе рrосеss оf рrоfеssiоnal sеlf-dеtеrminatiоn оf sсhооlсhildrеn, taking intо aссоunt thе faсtоr оf influеnсе оf thе living еnvirоnmеnt (сity оr villagе). Whеn соnsidеring this issuе, studеnts оf rural gеnеral еduсatiоn sсhооls dеsеrvе sресial attеntiоn, sinсе, mоst оftеn, thеy arе in рооrеr соnditiоns оf рrоfеssiоnal сhоiсе duе tо thе роvеrty оf additiоnal еduсatiоn, laсk оf industrial рrоduсtiоn in rural arеas, and insuffiсiеnt rеsоurсеs оf rural sсhools tо сrеatе thе nесеssary соnditiоns fоr vосational guidanсе.

In view of the fact that the endo-prosthesis heads of human hip-joint are operated in extreme conditions, in respect of load, the selection of corresponding material and also increase of precision and quality of machining of spherical surfaces is rather topical task. In the submitted work are reviewed the problems connected with definition of the influence degree of orientation of the sapphire crystal on its workability during diamond grinding with a butt of the ring and elaboration of the perspective, original scheme of formation of the incomplete spherical surface, particularly, of the sapphire head of endo-prosthesis of the human hip-joint.

In the domain of sheet metal forming for car bodywork the deep drawing process is one of the essential operations and finishes with the calibration of the final contour in the bottom dead center. At this point the demand for great accuracy is opposed to the highest press force inducing large deformations of the tool and the machine itself. The tool deformation is known from CAD and FEM, whereas the compensation of the machine elasticity is currently carried out only in a global and general way. This paper describes a workflow for the measurement and analysis of the individual elastic behavior of a forming machine’s most relevant components and their conversion into a FE model which is capable to be used in a simulation together with the tool geometry for determining the individual compensational camber of the tool. This workflow targets the enhancement of the current general empirical values with an individual deterministic approach for each machine and tool combination to reduce the overall time for tool manufacturing.

Today composite materials become increasingly more common to use for lightweight applications. This paper introduces a simulation approach for a handling and forming process. This process focusses on the robot based gripping, handling and forming of continuous-fiber-reinforced-thermoplastics, such as organo-sheet. The results of this paper show a manufacturing study of the heat transfer of a temperature-elevated organo-sheet during handling using heated needlegripper. Beside the fabric deformation, this research focuses on the temperature distribution during forming. Fast temperature drops lead to an increasing stiffness of the thermoplastic. Therefore, it is necessary to consider changing material parameters due to the temperature change. © 2019 The Author(s).

Some consequences follow from Veitsman’s theorem. It is supposed that the physical time in space dependences on the state of the system under study. If space is in equilibrium, then there is no time known to us from physics in it. If the space is anisotropic then the time is to be a vector.

One of the global problems today is energy—its production and distribution. As the human population grows, the consumption of energy rises simultaneously. However, the natural sources are limited, and so the focus on power savings becomes more and more important. One of the ways to reduce consumption is the use of effective lubricants and tribological fluids in industry, especially in processes with high demands on energy but high quality of products as well. Forming is a typical example of such technology, and the application of polymers seems to be a very important challenge, because the application of straight oils or lubricant with extreme pressure additives seems to be prevailing in that field. Nevertheless, the polymer lubricant should fulfill all European standards as well as the environmental and ecological limitations with respect to health and the natural environment and its recycling and disposal. This paper is focused on the forming technology of threads and the application of selected polymers to the forming process. The measured and quantified criteria are torque and force loadings, energy consumption, and quality of the produced surfaces. Kistler dynamometers, scanning electron microscopy, and advanced surface topography with the use of Alicona IF-G5 were applied to assess all aspects of the tribological and energy aspects of six modern process fluids, three lubricating pastes, and two fluid modifications. The results show that the polymer synthetic lubricant (at volume concentration 20% in water) can reduce the total energy consumption by up to 40% per forming cycle (in mean values) at average surface roughness below 0.8 m Jedním z globálních problémů současnosti je energie – její výroba a distribuce. Jako lidská populace roste, současně roste i spotřeba energie. Nicméně přírodní zdroje jsou omezené, a tak se zaměření na úspory energie stává stále důležitějším. Jeden ze způsobů, jak snížit spotřebu, je používání účinných maziv a tribologických kapalin v průmyslu, zejména v procesech s vysokými nároky na energii, ale i na vysokou kvalitu výrobků. Tváření je typickým příkladem takové technologie a aplikace polymerů se zdá být velmi důležitou výzvou, protože aplikace přímých olejů nebo maziv s přísadami pro extrémní tlaky v této oblasti převládá. Přesto by polymerní mazivo mělo splňovat všechny evropské standardy a také environmentální a ekologická omezení s ohledem na zdraví a životní prostředí přírodní prostředí a jeho recyklaci a likvidaci. Tento článek je zaměřen na technologii tváření aplikací vybraných polymerů do tvářecího procesu. Měřenými a kvantifikovanými kritérii jsou krouticí moment a silové zatížení, spotřeba energie a kvalita povrchů. Dynamometr Kistler, rastrovací elektronová mikroskopie a pokročilá povrchová topografie s použitím Alicona IF-G5 byly použity k posouzení všech aspektů tribologických a energetických aspektů ze šesti moderních procesních kapalin, tří mazacích past a dvou modifikovaných kapalin. Výsledky ukazují, že polymerní syntetické mazivo (při objemové koncentraci 20 % ve vodě) může snížit celkovou spotřebu energie až o 40 % na jeden tvářecí cyklus (ve středních hodnotách) při průměrné drsnosti povrchu pod 0,8 m.

The shear response of fabrics and fabric reinforced materials is primarily characterised by means of Picture Frame and Bias Extension experiments. Normalisation methods have been proposed earlier to enable comparison between different measurement results. Here, a continuum mechanics based analysis is presented for biaxial fabric materials without intra-ply slip, subject to constraints of fibre inextensibility. The fibre stresses are separated from the constitutively determined extra stresses, leading to a scalar equivalent stress resultant which makes the analysis of these tests more transparent. The equations are elaborated for both shear characterisation experiments and a direct measurement evaluation is proposed, without the need for iterative parameter identification methods.

This paper proposes a new joining by forming process to produce lap joints in metal sheets. The process combines partial cutting and bending with mechanical interlocking by sheet-bulk compression of tabs in the direction perpendicular to thickness. The lap joints are flat with all the plastically deforming material contained within the thickness of the two sheets partially placed over one another. The design of the lap joints is performed by a simple analytical model and the overall concept is validated by means of numerical modelling and experimentation. Destructive shear tests demonstrate the effectiveness and performance of the new proposed lap joints.

RRAM devices have been subjected to intense research efforts and are proposed for nonvolatile memory and neuromorphic applications. In this paper we describe a multiscale modeling platform connecting the microscopic properties of the resistive switching material to the electrical characteristics and operation of RRAM devices. The platform allows self-consistently modeling the charge and ion transport and the material structural modifications occurring during RRAM operations and reliability, i.e., conductive filament creation and partial disruption. It allows describing the electrical behavior (current, forming, switching, cycling, reliability tests) of RRAM devices in static and transient conditions and their dependence on external conditions (e.g., temperature). Thanks to the kinetic Monte Carlo approach, the inherent variability of physical processes is properly accounted for. Simulation results can be used both to investigate material properties (including atomic defect distributions) and to optimize stack and bias pulses for optimum device performances and reliability.

This article is aimed at extending the ‘mortise-and-tenon’ joining concept commonly utilized in corner or tee joints to lap joints in which one sheet is partially placed over another without any change in their shape. The approach makes use of wire arc additive manufacturing to fabricate the tenons and allows various shapes and thicknesses to be made from a wide range of metallic materials. Upset compression of the tenons is utilized to mechanically lock the two sheets being joined. Experimental and finite element simulation works performed with monolithic (aluminium–aluminium) and hybrid (aluminium–polymer) ‘unit cells’ consisting of a single lap joint are utilized to investigate the deformation mechanics and the feasibility of the new proposed joining process. Tensile-shear loading tests were carried out to determine the maximum force that the new proposed joints are capable to withstand without failure. Pull-out forces of approximately 8 and 6 kN for the monolithic and hybrid joints allow concluding on the potential of additive manufactured ‘mortise-and-tenon’ lap joints to connect sheets made from similar and dissimilar materials.

The impact of temperature during the forming operation on the electrical cells performance and the post-programming stability were evaluated in amorphous and polycrystalline HfO2-based arrays. Forming (between 40 and 150C), reset and set (at room temperature) operations were applied using the incremental step pulse with verify algorithm (ISPVA). The improvements achieved on the forming operation in terms of time and voltages reduction do not impact the subsequent reset/set results. ISPVA perturbations in LRS/HRS current distributions are almost negligible after the first reset/set operation. In this study the best improvement in forming operation in terms of yield, voltage values and cell-to-cell variability is achieved in polycrystalline samples at 80C. Display Omitted The impact of temperature during the forming in HfO2-based RRAM arrays was evaluated.Programming was applied using the incremental step pulse with verify algorithm.Raising temperature the voltages required in forming operation are reduced.The improvements achieved on the forming do not impact on the reset/set results.The best improvement in forming is achieved in polycrystalline samples at 80C.

Editor’s note: Retention time is one of the key parameters of emerging memories, which define the time duration the data can be retained when the power supply is removed. In this work, the authors investigate the forming voltage and the data retention of aluminum (Al)-doped HfO2-based RRAM devices and suggest a way to improve the device’s data retention time. ——Yiran Chen, Duke University

Research has been undertaken to investigate how the tensile strength efficiency and Z-strength efficiency in twin-wire roll forming is affected when changing formation through the softwood kraft content in a mixture with recycled pulp. The effect of a change in formation through the softwood kraft content and the effect of a change in formation through headbox consistency were also compared. Five kraft contents (0, 25, 50, 75 and 100%) were investigated at volumetric headbox flow rates of 111 and 1,77l/sm. Three additional flow rates were used at a kraft content of 50%. Impaired formation through the softwood kraft content reduced tensile strength efficiency and Z-strength efficiency. Both these properties were similarly affected whether the formation was changed by the softwood kraft content or the headbox consistency. The relative impact of formation was larger for Z-strength efficiency compared with tensile strength efficiency. The reduction in tensile strength efficiency was replicated in a smaller relative increase in tensile strength for machine-made paper than for handsheets made of the furnish. Considering the effect on strength efficiency when evaluating furnishes has been demonstrated as an important concern.

A finite element (FE) model has been developed to simulate the double diaphragm forming (DDF) process, to identify potential defects when forming complex 3D preforms from 2D biaxial non-crimp fabric plies. Three different metrics have been introduced to predict and characterise defects, which include local shear angles to determine ply wrinkling induced by over-shear, compressive strains in the primary fibre directions to determine bundle wrinkling, and tensile stresses in the primary fibre directions to determine fabric bridging. The FE simulation is in good agreement with experiments performed on a demonstrator component. Results indicate that fabric bridging occurs in large-curvature regions, which is the dominant defect in DDF, as wrinkling is generally lower than in matched-tool forming due to relatively low forming pressures (up to 1 bar). The axial tensile stress in fibres has been used as a measure to identify suitable positions and orientations for darts, to alleviate fabric bridging and improve surface conformity, whilst minimising the effect on the mechanical performance of the component.

The hot working behavior of a 38Ni-21Cr based superalloy was studied. Torsion tests at strain rates between 2 and 20 s-1and temperatures between 1123 and 1473 K were conducted. A fine microstructure of about 6-10 lm grain size and small TiC particles were observed after torsion tests at 1473 K and 4 s-1. The results of these tests were analyzed usingMATLAB and MS EXCEL programs to obtain the parameters of the Garofalo equation able to correlate the experimental data with a single equation. Stress exponent values much higher than 5 and a high activation energy for deformation suggest that the deformation is controlled by a slip creep mechanism characteristic of reinforced materials. The optimum forming temperatures at different strain rates were determined by means of the second Lyapunov stability equation. An optimum stability temperature of 1643 K (13708C) at 10 s-1is determined.

Рассматриваются вопросы процесса дозирования фарша в ячейки формовочного стола роторных котлетоформовочных машин и выполнения условия, при котором время движения формовочного стола над окном выдачи порции фарша будет меньше времени его дозирования в ячейку.

This work applies the Buckingham &Pi, theorem from dimensional analysis on superplastic processes in order to obtain laws of behaviour in a simple way. For this reason, a mathematical background is developed. The particular behaviour of superplastic materials makes it necessary to adapt the way in which these are treated, modelling them by a viscosity function of the strain-rate. Then, dimensional analysis is applied on a set of free-inflation tests in order to obtain a formula that defines the forming time as single function of geometric and material variables. Dimensional analysis allows us to reduce the number of variables to analyse from six to only three. Finally, two different forming time estimators are compared to measure the accuracy of our method, showing a significant improvement over previous methods.

In 1944, three decades before the start of the artisanal bread movement, H. E. Jacob published Six Thousand Years of Bread: Its Holy and Unholy History capturing bread’s cultural, political, religious, and technological impacts over time. In the introduction of the 2007 edition of the text, prominent American baker Peter Reinhart wrote that bread is “inextricably woven into our cultural and personal histories.” Reinhart notes that while bread does have its own story, “it is also the medium through which so many other stories are told: stories of escape from bondage; of historical and political battles ...; of the intermingling of the supernatural and mystical into the natural world” (vi). In the same way, Artisan: On Bread and a Meaningful Life, a collection of three nonfiction essays, utilizes aspects of the bread baking processing (kneading, shaping and communion) to explore and tell the author’s personal story with work, the body and the scared. Bouncing between the science and technique of bread and personal experiences related to these broader themes, this work sought to answer the question, what can bread tell us about what makes a balanced and meaningful life?

There is an opportunity to reduce the amount of sheet metal currently used to manufacture automotive components, despite the available cost and CO2 savings, the automotive industry has not realised the full potential of these saving opportunities. To understand why, a practical case study was set up with an automotive manufacturer. A cross-functional team was established with the scope to make changes to five components using a structured design process to improve material efficiency. The trial identified realistic opportunities to improve material utilisation by 20%pts, and save £9million and 5 kilotonnes of CO2 annually. The greatest saving opportunities were found early in the product development cycle, before the production method is determined by component geometry. Of these, 3%pts were actually implemented on the production vehicle, saving £1.8million and 1.5 kilotonnes of CO2 annually. The case study identified significant barriers to implementing material efficiency strategies in an industrial setting. To overcome these barriers material utilisation should be considered early in the product design process and high in the vehicle platform hierarchy. As a result of this investigation, new business processes are being generated to support design for material utilisation at the automotive manufacturer. This case study approach should be considered to increase implementation for other aspects of material demand reduction.

The Special Issue of the Manufacturing Engineering Society 2020 (SIMES-2020) has been launched as a joint issue of the journals “Materials” and “Applied Sciences”. The 14 contributions published in this Special Issue of Applied Sciences present cutting-edge advances in the field of Manufacturing Engineering focusing on advances and innovations in manufacturing processes; additive manufacturing and 3D printing; manufacturing of new materials; Product Lifecycle Management (PLM) technologies; robotics, mechatronics and manufacturing automation; Industry 4.0; design, modeling and simulation in manufacturing engineering; manufacturing engineering and society; and production planning. Among them, the topic “Manufacturing engineering and society” collected the highest number of contributions (representing 22%), followed by the topics “Product Lifecycle Management (PLM) technologies”, “Industry 4.0”, and “Design, modeling and simulation in manufacturing engineering” (each at 14%). The rest of the topics represent the remaining 35% of the contributions.

This paper starts from the early developments and working principles of the additive manufacturing of polymers, continues with a glimpse on the extension to metals with identification and characterization of the two most widespread technologies, and ends with an overview of the recent developments in hybrid metal additive manufacturing. Earlier classifications of hybrid manufacturing with roots on the utilization of primarily processed raw materials in the form of ingots, sheets, rods, tubes, profiles, powders and pellets are revisited in the light of the emergence of a new type of hybridization resulting from the combination of additive manufacturing with traditional manufacturing processes. Special emphasis is given to the combination of additive manufacturing with forming processes with the two-fold objective of (i) increasing the applicability domain of metal additive manufacturing and overcoming its limitations related to low productivity, metallurgical defects, rough surface quality and lack of dimensional precision, and (ii) adding flexibility and fostering new applications of traditional forming processes.

The demand for new processes to produce high strength parts, under appropriate cost and productivity, has grown with weight reduction and crash safety improvements in automobile design. The hot stamping processes of quenchable steel sheets potentially offer not only small forming load and high formability, but also high strength and no springback by die quenching. This paper aims to provide an overview of the state-of-the-art in such hot stamping processes, including quenchability, formability, heating and cooling approaches and lubrication. The paper also includes a description of the mechanism of formability and quenching, tailoring, analysis of hot stamping processes and applicability.

The metal forming and joining industries are constantly evolving to adapt to new materials and alloys and to meet customers’ needs. However, the size of the companies in this segment is typically small. Therefore, the progress of the mesomechanical modeling on non-homogeneous materials is relatively slow. This article aims to contribute to the advancement of such computational idea. The industries and academics alike may benefit the mesomechanical aspects of computational modeling for materials joined by forming using the established theories known in the field of mechanics. It may be used as an introductory for the society of joining by forming. This article reviews the basic concept of the finite element method, the fundamental mechanics and highlights some common problems in joining by forming, namely contact problems, local variations and interfacial cracking. This article aims to disseminate the meso/micro-mechanics approach to the field of joining by forming, which currently is dominated by experimental works and macroscopic modeling. Using the simple approaches discussed in this article, researchers with little or no background in computational mechanics can implement the concepts.

This study compares negative incremental forming (NIF) and positive incremental forming (PIF) processes by geometrical considerations, finite element method (FEM) analyses, and experimental evaluations. Conical frusta were manufactured starting from AA5052H19 aluminum alloy sheets using both techniques. The processes were also simulated with LS-DYNA software and a close correlation between the experimental and numerical results was observed. The analysis of forming forces, forming limit diagrams (FLDs), and sheets thinning highlights that the PIF technique allows one to reach higher formability and geometrical accuracy. Finally, the differences in terms of surface quality were also discussed.

The aeronautical sector is strategically important for the economic development of Mexico and has grown steadily over the last 10 years. Furthermore, it generates high added value for its products. In Mexico, the aircraft manufacturing sector mainly focuses on the fabrication of heat exchangers, seals, fuel ducts, and engine support rings. Currently, this sector is not involved in the manufacture of engine hot section components such as combustion chambers and turbine blades. Estimation of the associated costs enables assessment of the feasibility of fabricating such components. This study investigates the feasibility of establishing production lines for aeronautical combustion chamber fabrication in factories dedicated to the manufacture of aeronautical gas turbine engines.

With the implementation of environmental protection, sustainable development and conservation-oriented policies, components and parts of thin-walled welded tubes have gained increasing application in the aircraft and automotive industries because of their advantages: easily achieving forming and manufacturing process at low cost and in a short time. The current research on welded tube plastic forming is mainly concentrated on tube internal high-pressure forming, tube bending forming, and tube spinning forming. The focuses are on the material properties and characterization of welded tubes, finite element modeling for welded tube forming, and inhomogeneous deformation behavior and the mechanism and rules of deformation coordination in welded tube plastic forming. This paper summarizes the research progress in welded tube plastic forming from these aspects. Finally, with a focus on the urgent demand of the aviation, aerospace and automotive industries for high-strength and light-weight tubes, this paper discusses the development trends and challenges in the theory and technology of welded tube plastic forming in the future. Among them, laser tailor-welded technology will find application in the manufacture of high-strength steel tubes. Tube-end forming technology, such as tube flaring and flanging technology, will expand its application in welded tubes. Therefore, future studies will focus on the FE modeling regarding how to consider effects of welding on residual stresses, welding distortions and microstructure, the inhomogeneous deformation and coordination mechanism of the plastic forming process of tailor-welded tubes, and some end-forming processes of welded tubes, and more comprehensive research on the forming mechanism and limit of welded tubes.

International audience; The internal structure of composite materials is modified during manufacturing. The formation of woven prepregs or dry preforms changes the angle between the warp and weft yarns. The damage behaviour of the consolidated composite is modified by these changes of angle. It is important when designing a composite part to consider this modification when calculating the damage in order to achieve a correct dimensioning. In this paper, a damage calculation approach of the consolidated textile composite that takes into account the change in orientation of the yarns due to forming is proposed. The angles after forming are determined by a simulation of the draping based on a hypoelastic behaviour of the woven fabric reinforcement. Two orthogonal frames based on the warp and weft directions of the textile reinforcement are used for the objective integration of stresses. Damage analysis of the cured woven composite with non-perpendicular warp and weft directions is achieved by replacing it with two equivalent Unidirectional (UD) plies representing the yarn directions. For each ply, a model based on Continuum Damage Mechanics (CDM) describes the progressive damage. Two examples are presented, a bias extension specimen and the hemispherical forming coupon. In both cases, the angles between the warp and weft yarns are changed. It is shown that the damage calculated by taking into account these angle changes is greatly modified.

Рассматриваются вопросы расчета и оптимизации основных параметров роторных котлетоформовочных машин, обеспечивающих повышение производительности при формовке котлет круглой формы., The issues of calculation and optimization of the main parameters of rotary cutlet-forming machines, which provide an increase in productivity when forming round cutlets, are considered.

A model is proposed for describing the shape change of isotropic and anisotropic graphite under the influence of high temperatures and high neutron radiation fluences. The model is based on a new approach, which uses the following provisions: description of the near-pore neighborhood in graphite as a solid solution using the theory of phase transformations of the first kind; consideration of a new phase as a spheroidal pore of small eccentricity, flattened along the direction of greatest stress; taking into account the clustering of carbon atoms at fluences of more than . The graphite non-isotropy is characterized by different pore sizes, different diffusion coefficients, the lengths of the paths of graphite atoms along and across volume of the sample, which in turn depend on the temperature of the sample. It is proposed that the initial element on the basis of which a new phase will be formed is the spheroidal pore of small eccentricity, flattened along the direction of the highest tension. A kinetic equation that describes the diffusion of pores under the influence of high temperatures and intense neutron fluxes is obtained. Initially, the pores are in a field of predetermined stresses oriented along and across the sample. The contribution of diffusion processes is due to the term proportional to the pore distribution function in the sample, and the effect of the neutron flux is described by an additional term in the kinetic equation. The obtained kinetic equation for anisotropic graphite can be transformed for isotropic graphite. For isotropic and anisotropic graphite, model solutions have been obtained that characterize the change in its volume with time under the influence of a neutron flux and high temperature. It is shown that the magnitude of the change in the relative volume of reactor graphite for isotropic graphite exceeds a similar value for anisotropic graphite. Theoretical confirmation of the laws governing the swelling of anisotropic graphites under the influence of large neutron fluences and in the high-temperature field, previously obtained by other authors, is obtained: longitudinal compression of anisotropic graphite samples corresponds to a change in the linear dimensions of isotropic graphites; the transverse compression of anisotropic graphite samples is less than the change in the longitudinal linear dimensions of isotropic graphites.

Рассматриваются основные этапы расчета мощности привода роторных котлетоформовочных машин с оптимизированными параметрами при формовке котлет круглой формы из говяжьего и куриного фарша., The main stages of calculating the drive power of rotary cutlet-forming machines with optimized pa-rameters when forming round-shaped cutlets from beef and chicken minced meat are considered.

En este Trabajo Fin de Grado, se ha pretendido enfocar en los útiles de estampado en frio para la fabricación de componentes, entre otros del sector de la automoción. Veremos que propiedades ha de tener uno los aceros utilizados en la fabricación de componentes, las características físico - mecánicas y la ciencia química que le otorga características específicas. También la teoría que nos explica la manera de ser trabajado, junto a la normativa que se le es de obligatoria aplicación en criterios de calidad. Explicaremos la composición de un troquel, piezas y su funcionamiento, además de un repaso de la calidad del acero que lo compone. Concluyendo con la importancia de su mantenimiento y puesta a punto, crítico para el buen desempeño de dicha herramienta en su trabajo diario de 24 horas por 7 días a la semana. ABSTRACT: In this End of Degree Project, it has been tried to focus on the tools of cold stamping for the manufacture of components, among others of the automotive sector. We will see what properties must have one of the steels used in the manufacture of components, the physical-mechanical characteristics and the chemical science that gives specific characteristics. Also, the theory that explains the way to be worked, together with the regulations that are mandatory application in quality criteria. We will explain the composition of a die, parts and their operation, as well as a review of the quality of the steel that composes it. Concluding with the importance of its maintenance and fine tuning, critical for the good performance of this tool in its daily work of 24 hours for 7 days a week. Grado en Ingeniería Náutica y Transporte Marítimo

There has been increasing interest in the processes that enable part customization and small-batch production in recent years. The prosthetic sector, in which biocompatible materials are used, is one of the areas that requires these types of processes, Incremental Sheet Forming (ISF) technology can meet these requirements. However, the biocompatible thermoplastic polymers formed by this technology have not yet been tested. Hence, the aim of this paper is to cover this gap in our knowledge by analyzing the effects of process parameters on the ISF process with the aim of optimizing these parameters before the actual production of, in this case, customized prostheses. Tests with polycaprolactone (PCL) and ultra-high molecular weight polyethylene (UHMWPE) were performed. Maximum force, surface roughness and maximum depth were statistically analyzed by means of response surface methodology and survival analysis. Spindle speed and tool diameter were shown to be the most influential process parameters in terms of maximum forming force and surface roughness for both materials. In contrast, survival analysis applied to maximum depth showed a greater influence of tool diameter in PCL sheets and a greater influence of spindle speed in the case of UHMWPE.