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The global sales of carbon fiber reinforced plastics (CFRP) still grow in a double-digit percentage range. Alongside the aerospace industry, the automotive industry is the biggest driver of this growth. CFRP belong to the group of composite materials, but in fact represent structures made of high-strength fibers embedded in a polymer matrix. Currently CFRPs are no longer used on a large scale in automotive construction, but they are increasingly being used where they offer particular advantages in terms of weight saving, stiffness and strength. Ensuring strength is one of the key challenges. Damage patterns in CFRP are hardly to detect visually and are unknown within conventional materials. Currently there is a lack of measurement concepts for the detection, localization and quantification of damages that can provide the measurement data required for CFRP repair with sufficient uncertainty. This research project addresses the mentioned deficits by means of the conceptual design and experimental validation of an optically tracked ultrasound measurement system. In accordance with the research methodology of Design Science Research, the research results are generated iteratively and validated experimentally with the help of various experimental setups. The design process is coupled with the application area of an CFRP repair shop and the existing knowledge base of measurement technology. The conceptual design of the optically tracked measurement system, consisting of a phased-array ultrasonic measurement system and an optical tracking system, is based on a novel combination and real-time synchronization of the individual measurement systems. For this purpose, a measurement software for recording, visualization and evaluation of the measurement data is developed. The evaluation methodology is based on a sound intensity distribution modeling, novel methods of peakdetection and 3D reconstruction of the ultrasonic measurement data. The concept is validated with the help of calibrated test components. The uncertainty analysis is carried out in three steps with specifically designed test setups, followed by an analysis of the factors influencing the measurement process and the measured variables. The uncertainty analysis of the optical tracking system is performed by reference distance measurements of a coordinate measuring machine and by varying the limits of the parameter space. Subsequently, the influences of the phased array ultrasonic measurement system are analyzed by means of an experimental setup consisting of a linear axis traversing unit and series of measurements in immersion technique and optimized iteratively based on the calculated measurement uncertainty contributions. Ultrasonic measurement and optical tracking are tested in combination to examine the overall system and to optimize the software setting parameters. In the last step, it is shown that the measurement uncertainty can be sufficiently reduced for practical use by using optically measured surface data. The knowledge gained is based on novel algorithms for the model-based evaluation of the 3D reconstructed ultrasonic measurement data as well as the for the first time realized quantification of the hardware-, software- and process-related influencing factors on the uncertainty of the optically tracked ultrasonic measurement system. In addition, a method was developed to reduce the measurement uncertainty by combining ultrasound and surface measurement data for practical use.

Purpose – The presentation summarizes the state-of-the-art in aircraft end-of-life strategies. Methodology – A literature review is the basic research method utilized. A visit to a dismantling site complemented the findings. Journeys and the Internet show examples of special reuse approaches giving aircraft and components a second life. Findings – In the past aircraft went to "boneyards" at their end-of-live where they were simply left on their own. This should be avoided in the future. Instead aircraft are initially parked and stored. If no further operation is possible, aircraft are dismantled. Components and material is recycled as far as possible. The rest is disposed. Research has been done on the topic by Airbus, Boeing, other industrial companies, and academic institutions. The aircraft recycling industry starts to build up now by the launch of several recycling plants. The aircraft recycling market will slowly mature with associations like the Aircraft Fleet Recycling Association (AFRA) and with the publication of guidance material for best practices. The significant higher percentage of composites in modern aircraft types is a challenge for aircraft recycling. Special reuse approaches are only a niche market and not able to cope with the number of aircraft that need to be decommissioned each year. Value – The presentation gives a year 2022 overview on the state-of-the-art of aircraft end-of-life handling with many pictures., Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de

Dissertation, RWTH Aachen University, 2022; Aachen : Apprimus Verlag, Ergebnisse aus der Produktionstechnik 44/2022, 1 Online-Ressource : Illustrationen, Diagramme (2023). = Dissertation, RWTH Aachen University, 2022, The global sales of carbon fiber reinforced plastics (CFRP) still grow in a double-digit percentage range. Alongside the aerospace industry, the automotive industry is the biggest driver of this growth. CFRP belong to the group of composite materials, but in fact represent structures made of high-strength fibers embedded in a polymer matrix. Currently CFRPs are no longer used on a large scale in automotive construction, but they are increasingly being used where they offer particular advantages in terms of weight saving, stiffness and strength. Ensuring strength is one of the key challenges. Damage patterns in CFRP are hardly to detect visually and are unknown within conventional materials. Currently there is a lack of measurement concepts for the detection, localization and quantification of damages that can provide the measurement data required for CFRP repair with sufficient uncertainty. This research project addresses the mentioned deficits by means of the conceptual design and experimental validation of an optically tracked ultrasound measurement system. In accordance with the research methodology of Design Science Research, the research results are generated iteratively and validated experimentally with the help of various experimental setups. The design process is coupled with the application area of an CFRP repair shop and the existing knowledge base of measurement technology. The conceptual design of the optically tracked measurement system, consisting of a phased-array ultrasonic measurement system and an optical tracking system, is based on a novel combination and real-time synchronization of the individual measurement systems. For this purpose, a measurement software for recording, visualization and evaluation of the measurement data is developed. The evaluation methodology is based on a sound intensity distribution modeling, novel methods of peakdetection and 3D reconstruction of the ultrasonic measurement data. The concept is validated with the help of calibrated test components. The uncertainty analysis is carried out in three steps with specifically designed test setups, followed by an analysis of the factors influencing the measurement process and the measured variables. The uncertainty analysis of the optical tracking system is performed by reference distance measurements of a coordinate measuring machine and by varying the limits of the parameter space. Subsequently, the influences of the phased array ultrasonic measurement system are analyzed by means of an experimental setup consisting of a linear axis traversing unit and series of measurements in immersion technique and optimized iteratively based on the calculated measurement uncertainty contributions. Ultrasonic measurement and optical tracking are tested in combination to examine the overall system and to optimize the software setting parameters. In the last step, it is shown that the measurement uncertainty can be sufficiently reduced for practical use by using optically measured surface data. The knowledge gained is based on novel algorithms for the model-based evaluation of the 3D reconstructed ultrasonic measurement data as well as the for the first time realized quantification of the hardware-, software- and process-related influencing factors on the uncertainty of the optically tracked ultrasonic measurement system. In addition, a method was developed to reduce the measurement uncertainty by combining ultrasound and surface measurement data for practical use., Published by Apprimus Verlag, Aachen

Purpose - The report summarizes the state-of-the-art in aircraft end-of-life strategies. A focus is on latest aircraft types with a high percentage of composite materials. --- Methodology - A literature review is the basic research method utilized. Apart from books, journals, conference proceedings, and dissertations, also technical reports and industrial news have been included into the search results. The field of aircraft end-of-life is still comparatively small, resulting in a manageable amount of literature addressing the topic directly. --- Findings - Research has been done on the topic by Airbus, Boeing, other industrial companies, and academic institutions. A market for recycled material is missing. Regulations about aircraft recycling are strongly needed but are not foreseeable in the near future. Nevertheless, the trend goes to extended producer responsibility. The aircraft recycling industry starts to build up now by the launch of several recycling plants. The aircraft recycling market will slowly mature with associations like the Aircraft Fleet Recycling Association (AFRA) and with the publication of guidance material for best practices. The significant higher percentage of composites in modern aircraft types is a challenge for aircraft recycling. --- Research limitations - The study provides only an overview on the aircraft end-of-life sector. Further research needs to be done on individual specific aspects. --- Value - The paper gives a year 2020 update on the state-of-the-art of aircraft end-of-life handling, including an overview on composite recycling regarding latest aircraft types.