Fraunhofer Institute for Structural Durability and System Reliability LBF Safe. Digital. Sustainable. Annual Report 2022

Index 2022 at a glance Insights Safe. Digital. Sustainable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Current members of the Board of Trustees . . . . . . . . . . . . . . . . . . . . . . . 7 Fraunhofer LBF in numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Systematic Research! Digital Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Smart Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Reliability Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Circular Economy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Lightweight Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Future Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Insights Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Research Divisions Structural Durability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Smart Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Plastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Insights LBF Management Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 The annual report 2022 – digital www.lbf.fraunhofer.de/annual-report 3

Insights Safe. Digital. Sustainable. Dear customers and partners of Fraunhofer LBF, Safe. Digital. Sustainable. This is the motto that defines our institute’s agenda for the future. In 2022, we once again aligned our key research topics according to that motto: from the development of digital models for components and systems, through deve- lopment methods and simulation strategies for designing, analyzing and safeguarding critical products, right up to creating concrete, circular material and system solutions. In our numerous research projects, we are expanding our scientific and technological market offerings for polymer materials, durable and intelligent lightweight design, structural dynamics and experimental, digital and cyber-physical simulations. What matters most to us is providing our customers and partners with optimal support as they increase resource and energy efficiency, sustainability and innovation in all product life cycle phases and value chain stages. Highlights of our work in the area of safety and reliability in 2022 included establish- ing the Smart Lab for Future Mobility Chassis Systems. In this modular system, our institute now has a cutting-edge laboratory environment for simulating operating loads for complex and even active component assemblies in automotive engineering systems. The smart lab was set up as an expertise and application center, but it will also promote the transfer of research results to industry. Vibroacoustic metamaterials (VAMM) have been a core area of research at Fraunhofer LBF for many years, forming the focus of numerous smart and digital technology projects in the fields of mobility and infrastructure engineering. Our most recent achievement in this domain saw our researchers develop a prototype for noise-insu- lating walls as part of their investigations on how to better protect residents affected by road traffic noise. Using metamaterials significantly improved transmission values in comparison to the conventional method of increasing insulation wall thickness. ASFINAG, the Austrian public corporation that manages the country’s highways, is currently planning to implement the materials in practice. In the last year, our scientists have also worked to drive sustainability in multiple projects on clean, eco-friendly technology. These projects include efforts to develop biobased, biodegradable plastic solutions with a high technical quality level from recycled materials. In 2022, we also expanded our expertise in the field of recyclable plastics. In addition, we launched and implemented multiple new projects in two of our key research fields: smart, durable lightweight design and resource efficiency. 5

Insights Current members of the Board of Trustees Thank you very much! Dr. Xenia Beyrich-Graf BASF SE, Ludwigshafen Dr. Matthias Decker Audi AG, Ingolstadt Dr. Mathias Glasmacher Diehl Stiftung & Co. KG, Nuremberg Dr. Martin Hillebrecht EDAG Engineering GmbH Prof. Dr. Tim Hosenfeldt Schaeffler Technologies AG & Co. KG, Herzogenaurach Ministerial councilor Dr. Ulrike Mattig Hessian Ministry of Higher Education, Research, Science and the Arts, Wiesbaden Prof. Dr. Matthias Oechsner Technical University of Darmstadt Dr. Kurt Pötter BMW Group, Munich Rainer Salomon Research Association for Steel Application (FOSTA), Düsseldorf Florian Sprenger Dr. Ing. h.c. F. Porsche AG, Weissach Ministerial councilor (retired) Norbert Michael Weber 7

Fraunhofer LBF in numbers 2022 29,2 million € Total budget 33,3 % Economic income 10,4 % rest 20,0 % EU 69,6 % Germany 26,1 % Public income 10,9 % EU 1,2 % Other income 89,1 % Federal and state governments Operational budget 2022 [T €] Economic income Public income Other income Internal programs Institutional funding (Grufi) Total 9.780 7.629 365 4.333 7.179 29.226 3 2 0 2 l i r p A : s u t a t S 9

Using resources wisely for secure, stable and efficient processes Industrial value creation is characterized by ever shorter product life cycles and, at the same time, increasing product diversity – sometimes with individually tailored properties – as well as the distri- buted development, realization and use of products. In addition, there are increasing requirements for sustainability and resource efficiency, as well as increased functio nal complexity of systems in different opera- ting and usage scenarios. We develop the tools to make your digital product development efficient.” Against this background, product develop- ment processes are coming under increa- sing pressure in terms of efficiency, costs and flexibility, e.g. due to the reduction of available prototype systems or the increasing need for early decision-making and safeguarding processes to accompany Digital Engineering development. Alternative development tools and realistic digital models are there- fore needed to ensure that the require- ments for quality, safety and reliability of the products can still be met. The aim here is to increase the predictive quality of the actual component and system behavior through suitable modeling in such a way that, among other things, the number of prototype systems can be reduced and physical validations can be supplemented and optimized by virtual analyses. In the Digital Engineering area of expertise, researchers are developing new methods and, where necessary, customized tools that aim to virtually map development, safeguarding and valida- tion processes. For instance, innovative modeling and simulation solutions allow for extended functional properties in plastic components and in mechanical systems to be considered in the early design and realization process already. At the same time, usage data from practice, production and operation are integrated for validated modeling and simulation. This allows influences, stresses or damage at the material, component and overall system level to be realistically digitally reproduced. In this way, the number of possible variants for the later realization of a product can be reduced to a mini- mum at an early stage of the design and development process. 11

Digital Engineering DNAguss: Multicriteria optimization of casting components Optimizing castability, lightweight design, structural durability and validation Future project In German, DNAguss draws its name from the notion of fully digital design of casting compo- nents along the entire process chain. This research project is focused on optimizing the development process of casting components, based on the example of the material EN-GJS-400- 18-LT. The goal is to combine all the software tools used during the con- struction process for casting compo- nents within one software chain, with a view to optimizing castability, light- weight design and non-destructive testing while simultaneously ensuring structural durability. The development and design process for casting components usually consists of multiple steps in which diffe rent software solutions are used for a range of issues and optimization stages. The DNAguss team is taking an interdis- ciplinary approach, combining topology and forming optimization, casting process simulation, structural mechanics and structural durability in order to opti- mize the lightweight design of casting components. This sequence of interlinked software tools opens up entirely new possibilities for the design of casting components. By integrating all the software tools used in the design process into a single software chain, developers can optimize castability, lightweight design, structural durability and non-destruc tive testing of components and adjust these parameters to suit each other. This enables improved structural design, reduced component weight and lower manufacturing costs, while simultaneously ensuring structural durability. Further information online www.lbf.fraunhofer.de/ dnaguss-en Contact Felix Reissner +49 6151 705-302 SOFTWARE CHAIN, LIGHTWEIGHT DESIGN, OPTIMIZATION felix-christian.reissner@ lbf.fraunhofer.de The DNAguss software chain represents an innovative approach to improving the lightweight design potential of cast components. 13 DNAguss Software ChainStartLightweight designintermediate processCastabilityTestabilityStructural durabilityEndFEMTopologyoptimizationCasting proc.simulationService lifeassessmentShapeoptimizationLocalmicrostructureNDTsimulationManual constructionManualsmoothingOptimizedcomponentBoundaryconditions

Digital Engineering Further information online www.lbf.fraunhofer.de/ ai-damage-analysis Efficiently analyzing elastomer failure – with AI. AI failure analysis of technical elastomers Developing an automated detection process for elastomer failure Fraunhofer project Elastomer failure needs to be detected quickly and easily – but how? Due the variety of failure patterns that occur on elasto- mer components, it is not always easy to establish the exact cause of a failure. In the internal Fraunhofer project, AI Failure Analysis of Technical Elasto- mers, researchers are exploring the possibility of objectively analyzing elastomer failures through artificial intelligence. The resulting process will be transferred to customer-specific applications at a later stage. The standard VDI 3822 can be used as a basis for analyzing component failure. However, in this process, experience, expertise and the occurrence of similar failure patterns with differing failure causes can lead to a subjective assess- ment of the failure. In this project, Fraunhofer researchers hope to automate this time-consuming and cost-intensive process and make it more objective. They also hope to explore the conditions (i.e., input parameters, training data base, extrapolation potential, etc.) that would be required for practical implementation. Contact Franziska Kirsch +49 6151 705-8646 franziska.kirsch@ lbf.fraunhofer.de Riccardo Möller +49 6151 705-408 riccardo.moeller@ lbf.fraunhofer.de To begin with, the researchers are work- ing on a process chain that covers every step from image capturing to reliable analysis of varying forms of component damage; the chain will also include additional material and process param- eters. Once the detection, analysis and matching of failure causes and failure patterns are achieved successfully, the team will conduct a detailed analysis of the model’s scope of application by varying the component or type of failure. In the process, they will study factors such as the influence of scaling effects or the position and shape of the damage, so that they can draw conclusions regarding any generalization errors the model makes. They will use these findings as a basis for investigating whether the process can be transferred to other use cases. ELASTOMERS, FAILURE CAUSE, FAILURE ANALYSIS, AI, MULTIPLE INPUT VARIABLES 15

Smart Solutions Everything in view and everything under control to increase technical availabilities Intelligent sensor technology for the targeted collection and assessment of large amounts of data, increasing networking, function distribution and real-time, cross-system data communication, as well as function enhancement and mechatronization, are all drivers of digitization in modern products. Artificial intelligence and data­based services not only enable process chains in production to be analyzed, simplified and optimized. In fact, they also allow for structural monitoring that is adapted to current environmental and operating conditions, as well as actively influencing factors such as the vibration characteristics of machines and vehicles. Innovative materials and AI-based solutions for intelligent condition monitoring and noise control.” In the Smart Solutions area of expertise, scientists are researching and developing hardware and software solutions, based, among other things, on digital engineering modeling approaches, for smart maintenance applications, for predicting and preven- ting unplanned machine and system failures, and for increasing technical availability. Another topic is the targeted influencing of the vibration­related properties of struc- tures in mobile systems such as vehicles and in machines and systems. In both cases, machine learning methods are used for the advanced analysis of growing volumes of data, in conjunction with intelligent sensors and sensor networks, as well as integra- ted actuator technology. In this context, work with so-called metamaterials is going even further. These have high potential for the structurally­integrated influencing and adjustment of qualities such as acoustic or structural dynamic properties for the pur- pose of the reduction or alternative adjustment undesirable or harmful vibrations and sound radiation. The linking of methods established in relation to reliability as well as in vibration and materials engineering with new data-driven, digital approaches that the work aims to achieve is moreover an important building block for the development and realization of intelligent lightweight structures. 17

HyMon: intelligent tanks for hydrogen vehicles Sensor-based condition monitoring for vehicular pressurized hydrogen containers made from FRP high levels of stress. Containers made from fiber­reinforced plastics have far less mass than metal tanks and can operate at the same pressure. This makes them an attractive option for the mobility and transportation sector. They are designed for a service life of up to 20 years, at operating pressures of 200 to 1,000 bar. At present, containers in automotive applications have to undergo a visual inspection every two years. However, this a purely external assessment does not allow the inspector to come to any con- clusions regarding the internal state of the thick, fiber­reinforced composite material. If pressurized containers had a built-in structural monitoring system based on suitable sensors and analysis electronics, structural health monitoring data (SHM data) could be used to make the assess- ment more objective. In the future, a system like this could enable continuous monitoring in H2 fuel cell vehicles (H2 FCEV). Going forward, in addition to supporting repairs and servicing, SHM data may also be used to help suggest targeted measures for safe vehicle recov- ery during rescue missions in the event of vehicular accidents or misuse. Automated metrological monitoring of pressurized fiber-reinforced plastics containers makes them safer. Future project Fraunhofer research- ers have developed technologies for automated condition monitoring in high-pressure storage systems. These technologies can distinguish between critical and non-critical events during operation, meaning that simply replacing the containers at scheduled intervals is no longer necessary. This reduces the costs involved without impacting safety. As such, this devel- opment may help fulfill yet more of the requirements for establishing hydrogen technologies on a broad scale. Pressurized containers for storing gaseous fuels are a core element of H2 propulsion systems for motor vehicles; however, as safety components, they are also under HYDROGEN, H2, TANKS, PRESSURIZED CONTAINERS, FIBER-REINFORCED PLASTIC, FIBER-REINFORCED COMPOSITE Smart Solutions Contact Johannes Käsgen +49 6151 705-613 johannes.kaesgen@ lbf.fraunhofer.de Julia Decker +49 6151 705-491 julia.decker@ lbf.fraunhofer.de funded by: Further information online www.lbf.fraunhofer.de/ hymon-en 19

Smart Solutions Noise-insulating walls with vibroacoustic metamaterials More peace and quiet for people and animals Industry project ASFINAG, the Aus- trian public corporation that manages the country’s highways, has commis- sioned Fraunhofer LBF to develop a prototype of a noise-insulating wall based on vibroacoustic metamaterials (VAMM). Vibroacoustic metamaterials are a novel technology for dampening vibrations and noise. By adding vibro- acoustic metamaterials to a section of an acrylic noise-insulating wall, scientists achieved a significant reduc- tion in the transmission of the typical frequency range for road traffic noise. To identify innovative solutions for noise insulation on autobahns, ASFiNAG and the IÖB (the Austrian public procurement body for promoting innovation) launched a competition calling for technologies for reducing autobahn and highway noise. Fraunhofer LBF won out over the many other submissions with its solution for improving the transmission properties of noise-insulating walls using vibroacoustic metamaterials. The institute went on to conduct a joint research and development project with ASFiNAG, whereby an acrylic noise-insu- lating wall was equipped with a resona- tor array so that its sound transmission properties could be investigated. For the resonators, the team used 3D-printed plastic membrane resonators with a steel cylinder inside to serve as a mass element. Measurements conducted at Fraunhofer LBF’s acoustics laboratory have shown that the VAMM principle can reduce transmission through the noise-insulating wall much more effectively than other measures, such as doubling the wall’s thickness. VAMMs can also be used for absorbent noise-insulating walls in cas- sette construction or wooden noise-insu- lating walls. The VAMM technology could also offer benefits for other sectors. Further information online www.lbf.fraunhofer.de/ noise-control Contact Sebastian Rieß +49 6151 705-378 sebastian.riess@ lbf.fraunhofer.de 21 Developing a noise-insulating wall with vibroacoustic metamaterials. NOISE INSULATION, VIBROACOUSTIC METAMATERIALS, SOUNDPROOFING

Reliability Design Achieving more with less in terms of complexity, stability and reliability Ever lighter material solutions and structures on the one hand and ever more complex products and systems on the other are shaping product development in many industrial sectors. At the same time, however, the requirements regarding the reliability of such systems are increasing. After all, malfunctions and failures in this context can quickly have critical economic, ecological or health effects. Our research makes reliable products possible by using reliable processes.” The Reliability Design area of expertise represents a key scientific focus of Fraunhofer LBF. This is not just a matter of ensuring the service life of materials, components and products. Rather, the research and development activities in this area of expertise are aimed at understanding and describing all phases of product development, use and application along with their interactions, in an increasingly comprehensive manner, so that validation and assurance processes can be continuously moved forward into the early design process. In the spirit of “design to reliability”, digital engineering solutions are linked with new design and simulation methods. Based on realistic application data in relation to typical mechanical, climatic, electrical and combined multiphysical loads, tools and processes are being developed that take into account the reliable design of structures as early as the design stage. In this way, “safety margins”, which, in many cases, are still common today, can be reduced further and further in the future while maintaining or increasing the reliability of materials, components and products, thus enabling modern solutions that push the limits of what is feasible. 23

Reliability Design SmartLab4Chassis – Smart Lab for Future Mobility Chassis Systems Investigating chassis systems in current and future vehicle designs Future project The European auto- motive industry is changing. The integration of electronic components and expansion of electromobility is making vehicles highly complex and – largely due to the high mass of high-voltage energy storage systems – increasingly heavy. This means that traditional processes for testing struc- tural durability are no longer suitable for reliable development of such vehi- cles, nor for validating a service life of at least 15 years or 300,000 km. In addition, the future customer requirements will give rise to entirely new vehicle and chassis types. At its Kranichstein location, Fraunhofer LBF has established a smart lab for the development, functional verification and validation of the frame and chassis systems that will be used in future vehicles with alternative propulsion systems. As an expertise and application center, the Smart Lab for Future Mobility Chassis Systems aims to promote faster transfer of research findings into industrial applica- tion, and to make a substantial contribu- tion to the development of low-emission mobility vehicles. When combined with the vehicle road simulator, which has been operating successfully since 2012, this constitutes a cutting-edge laboratory environment for simulating operating loads in complex Further information online www.lbf.fraunhofer.de/ smartlab4chassis-en assemblies and systems. Specifically, the team behind the smart lab has procured and put into operation a road simulator for vehicles weighing up to a maximum allowable weight of 4.5 tons, and a servo­ hydraulic laboratory facility for active suspension/damper and air suspension systems with the capacity to superimpose a simulated environment (temperature, humidity). Real-time hardware is available that allows both systems to be controlled “in the loop” to test out new control requirements, or model the behavior of an entire system, for example. Contact Marc Wallmichrath +49 6151 705-467 marc.wallmichrath@ lbf.fraunhofer.de 25 Road simulator for validating entire vehicle frames. VEHICLE FRAME, AIR SUSPENSION, ACTIVE DAMPERS, STRUCTURAL DURABILITY VERIFICATION, FUNCTIONAL VERIFICATION, HIL

Plastics all charged up Materials for electrifying and decarbonizing the economy Industry project It is impossible to imagine the electrical and electronics sectors without the use of plastics. Their easy malleability and outstand- ing insulation properties have abso- lutely revolutionized these sectors. For instance, elastomers are used in cable insulation, thermoplastics in housings or equipment cabinets, along with thermoset polymers in circuit board materials or high-voltage insulators. It is vital in every case to describe the plastic or compound in terms of its electrical properties to ensure that it can be used in the relevant application. While with some applications, such as the material on the reverse side of solar cells, it is vitally important to have a very small amount of electrical conductivity to help prevent current leaks and long-term cor- rosion, this can cause problems in other cases, e.g., due to electrostatic discharge. Occasionally, good electrical conductivity is required, for instance, for bipolar plates in fuel cells or conductive textile fibers. With the wide range of applications, materials and shapes of components involved (plates, tubes, coatings, etc.), adapted measurement and description methods are often required. The scientists at Fraunhofer LBF apply their extensive expertise in a host of projects that involve Reliability Design Further information online www.lbf.fraunhofer.de/ plastics-under-electricity Measuring cell for measuring volume conductivity and surface conductivity of plastic films and plates. both adapting and developing methods for characterizing electrical properties, such as electric strength, surface con- ductivity or permittivity of elastomers, thermoplastics, and thermoset polymers. Fraunhofer LBF has a comprehensive range of state-of-the-art laboratory equipment available for these projects. Researchers are also developing specific measurement devices for customers. SUSTAINABILITY, ELECTRICAL MEASUREMENT, EFFICIENT PRODUCT DEVELOPMENT Contact Dr. Dirk Lellinger +49 6151 705-8667 dirk.lellinger@ lbf.fraunhofer.de 27

Plastics in hydrogen applications Innovative design, safe design, reliable testing Future project Hydrogen and its associated technologies play a sig- ni ficant role in achieving decarboni- zation goals and securing energy supplies. The reliability of materials in corresponding systems is crucial to their implementation. Research at Fraunhofer LBF focuses not only on metals, but also on materials made from plastics. Plastics are a key factor in the design of sustainable, weight-optimized light- weight structures. They are used in housings and bipolar plates for fuel cells, in pressure tanks, and in component seals or pipelines. In the future, a multitude of existing plastic-based systems will be used in the hydrogen field (e.g., in the natural gas network). For the majority of these materials, however, only a very limited amount of knowledge is available regarding their behavior in the hydrogen context, particularly in the long term. The primary focus here is on influences on their mechanical properties, chemical and physical aging, sorption or diffusion char- acteristics, and swelling properties during media absorption. At Fraunhofer LBF, in the course of our work on publicly funded research and bilateral customer projects, our unique combination of interdisciplinary expertise in the areas of materials development, analytics, materials testing and design methods allows us to devise solutions for reliable plastic components for hydrogen technologies. Structural simulations allow researchers to incorporate these results when developing methods for component design. HYDROGEN, PLASTICS, MATERIAL VALIDATION * These activities are embedded in the hydrogen high-performance center GreenMat4H2. Further information online www.lbf.fraunhofer.de/ hydrogen-applications Contact Dr. Felix Dillenberger +49 6151 705-8753 felix.dillenberger@ lbf.fraunhofer.de 29

Reliability Design Model for testing service life under combined mechanical and hydraulic stress conditions Investigating service life in elastomer components mechanical-hydraulic stresses that involves media separation. The central element in this approach is the use of a flat membrane for the separation. This new experimental assembly allows realistic operating load signals to be applied to elastomer pump components in order to verify service life. The experimental assembly enables the transfer of compa- rable load mechanisms from the field into the laboratory environment, thus improv- ing product quality. ELASTOMERS, WÖHLER EXPERIMENTS, MECHANICAL AND HYDRAULIC LOADS Experimental service life verification methods at Fraunhofer LBF bring improved product quality. Further information online www.lbf.fraunhofer.de/ evaluation-concept Contact Riccardo Möller +49 6151 705-408 riccardo.moeller@ lbf.fraunhofer.de Industry project When investigating component service life, the value of a test is determined by its ability to real- istically simulate all relevant stresses under real-life operating conditions. Pump components are subject to both mechanical and hydraulic stresses. The local elongation maxima of the respective elastomer components are established by superposing both types of stress. These elongation maxima play a crucial role in determining service life. Synchronous application of both stresses serves to establish ser- vice life and improve product quality. Pressure transducers can be used to great effect to generate hydraulic stresses on components. These typically use hydrau- lic oil as a medium for directing stresses and building pressure. Elastomer compo- nents should only come into contact with media actually used during operation, or other media that are compatible with the former. Unless explicitly intended, direct contact with hydraulic oils must be prevented. As such, particular attention must be paid to hydraulic oils’ excellent lubrication properties when it comes to generating pressure to prevent wear in piston cylinder pairs and the elastomer samples compatibility with the media. Fraunhofer LBF and Robert Bosch GmbH have taken an approach to applying 31

Exploiting the potential of high-strength wrought aluminum alloys in lightweight design You can find more information online www.lbf.fraunhofer.de/ allegro-en Cross-section of a laser-welded seam in EN AW-7075 metal sheet with a superimposed finite element mesh. Exploiting the potential of high-strength wrought aluminum alloys in lightweight design Assessment of unconventional process technologies for wrought aluminum alloys in the 7xxx series Contact Andre Jöckel +49 6151 705-652 andre.joeckel@ lbf.fraunhofer.de Dr. Benjamin Möller +49 6151 705-8443 benjamin.moeller@ lbf.fraunhofer.de Future project The demand for increased ranges of electric vehicles makes it necessary to further exploit the potential of lightweight materials. Al-Zn-Mg-Cu alloys of the 7xxx series exhibit high lightweight potential due to their high static strengths at low mass density. Due to the challenges of forming and joining these alloys, process-related fatigue strength assumes a key role for their future use in lightweight design applications. In the LOEWE focus area “ALLEGRO”, forming and welding processes were developed to realize high-quality joints consisting of the high-strength alloy EN AW-7075. In this process, the Fraun- hofer LBF carried out fatigue strength investigations using specially developed electro-mechanical and piezo-actua- tor small-load test rigs. These enable energy-efficient tests on miniaturized and locally removed specimens with a minimum length of 35 mm. Through “reverse engineering” and based on 3D laser scans as well as metallographic cross-sections of the joining area, finite element models were created. The alloy EN AW-7075 is considered to be weldable only to a limited extent. According to the cur- rent state of research, dissimilar joints with additively manufactured struc- tures often lead to defects in the join- ing area. Nevertheless, it was possible to demonstrate a fatigue strength in a range of welded 5xxx and 6xxx wrought aluminum alloys on the basis of the local notch stress approach for butt-welded and overlapping magnet- ic pulse welded joints with additively manufactured AlSi10Mg. PROCESS-RELATED STRUCTURAL DURABILITY, FATIGUE LIFE APPROACHES, CYCLIC MATERIAL BEHAVIOR 33

Circular Economy Renewable and upcyclable raw materials also for demanding technical applications Plastics are an integral part of our every- day lives. They offer the widest range of options in material technology solutions for a large number of applications. A wide range of properties can be imprinted in a targe ted manner: Foodstuffs are hygieni- cally packaged in a safe and durable way using plastics. As insulating and sealing materials with special fire protection properties, they are a modern building material. As engineering plastics, they offer effective and efficient functional features and lightweight design potential in primary and secondary components – often being shaped in a highly complex manner with defined insulating, vibration damping, sensory or actuator functions. Yet while their extraordinarily positive tech- nical properties cannot be denied, plastics are increasingly the subject of critical discussion. They are emblematic of modern environmental problems, in the form of microplastics or the pollution of the oceans, which we help to reduce through our research work. In the Circular Economy area of expertise, Fraunhofer LBF scientists are working on sustainable, durable and environmentally compatible plastics solutions, from the molecule, formulation and chemical-physi- cal characterization to synthesis and vali- dation, from use to the “end of life” and recycling – thereby transforming linear processes into circular ones. The particular strength of LBF is the profound expertise in additivation of plastics in order to adapt highly­specific material properties. Thus, biopolymers made from renewable raw materials can also be adjusted and upgraded for demanding technical applications in terms of their service life, degradation or performance. Beyond that, innovative additive systems allow for enhanced processability and improved end properties for recycled material. Additive systems can significantly expand the possibilities for material recy- cling of conventional polymers in terms of upcycling. Another field of research invol- ves the development of bioadditives as substitutes for commercial systems which, in terms of quality and performance, achieve comparable properties to conventional additives and in some cases significantly surpass them, e.g. for the weather resis- tance or flame retardancy of polymers. 35

Circular Economy Sorted and washed post- consumer polyethylene waste broken down into flakes. Recyclate analytics: developing a modern analytics process for post-consumer waste Analyzing sorted PE and PP waste Industry project Plastic products from recycled materials are becoming ever more important commercially, and support the circular economy. Fraunhofer LBF has created a cutting- edge, high-performance analytics system for sorted post-consumer PE and PP waste. The system allows the sorted objects to be character- ized in detail, providing information on whether they contain foreign polymers, additives, volatile organic compounds (VOC) and metallic impu- rities. This information is essential for evaluating material properties that may affect their possible applications. This opens up new possibilities for developing innovative recyclates in a targeted way. Plastics get a second chance at life plastics with the widest range of possible applications. A key challenge in develop- ing plastic recyclates from this material flow lies in analyzing the different chem- ical compositions of the sorted PE and PP waste in detail and finding a representa- tive way of displaying the analysis results for the entire waste load. For this reason, Fraunhofer LBF researchers are developing customized sampling and preparation processes that take statistics into account so as to ensure optimal representation. Contact Dr. Frank Malz +49 6151 705-8763 frank.malz@ lbf.fraunhofer.de Dr. Robert Brüll +49 6151 705-8639 robert.bruell@ lbf.fraunhofer.de This analytical range is suitable for a broad spectrum of waste streams. As these processes cover the analysis of non-poly- mer impurities, they also address regu- latory concerns and issues in processing. This opens up new material and process development opportunities for recyclate developers and processors. Further information online www.lbf.fraunhofer.de/ recyclates-analytics After polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) are the most common commercially used CIRCULAR ECONOMY, RECYCLATES, ANALYTICS 37

Circular Economy Improved management of fluctuating material flows. PET secondary materials from different post-consumer sources Influence of the characteristics and formulation of recycled materials on material properties Future project Fraunhofer LBF has collaborated with EASICOMP GmbH to lay the foundations for producing long glass fiber-reinforced thermo- plastics (LFT) from post-consumer recycled materials outside of the conventional bottle recycling cycle based on polyethylene terephthalate (PET). Identifying suitable material flows presented a significant chal- lenge for the researchers; what’s more, the flows in question fluctuate more intensively in terms of material composition, aging and delivery form when compared to virgin plastics or PET from bottles. In the UpcyclePET project, a new LFT material has been developed based on used PET drinks bottles. In UpcyclePET- Plus, the research team worked to develop secondary raw material sources that cannot yet be used in high-quality recy- cling processes. They are planning obtain to new sources of post-consumer raw materials for the LFT material from PET tray fractions from household recycling collections and PET from commercial and industrial waste flows. To identify the most suitable additive strategy for the respective material flow, the researchers need to know the exact composition of input material flow, and must identify and evaluate critical contaminants. They can then determine the type and content of suitable additives and adapt the formula. The LFTs that the Fraunhofer researchers were able to develop from the new mate- rial flows have comparable properties to those developed in a previous project. In comparison to LFTs based on PET bottles, which, according to the life cycle assess- ment by the Öko­Institut, produce 5.1 CO2 equivalent/kg, the new LFT has a reduced CO2 footprint of 3.8 – 4.4 CO2 equivalent/kg. PLASTIC ADDITIVES, UPCYCLING, SUSTAIN- ABILITY, SECONDARY RAW MATERIALS Further information online www.lbf.fraunhofer.de/ upcyclepetplus-en Contact Dr. Frank Schönberger +49 6151 705-8705 frank.schoenberger@ lbf.fraunhofer.de Shilpa Khare +49 6151 705-8739 shilpa.khare@ lbf.fraunhofer.de 39

Lightweight Design More efficiency for commercially successful products thanks to lightweight technology Lightweighting has long since ceased to be a “technical niche solution” for aircraft and innovative sports vehicles. Rather, affordable lightweight solutions for the best possible mass and energy efficiency in all mobile systems – such as in the produc- tion and operation of products – are key is possible even further. This is based on holistic knowledge at the level of materi- als, components and system technologies. In addition, methods of material construc- tion as well as those of constructive and systemic lightweight design are combined. Fraunhofer LBF pools its expertise in the research areas of plastics, structural dura- bility and smart structures and develops novel solutions from function-integrated, intelligent lightweight design, always With our research, we are pushing the boundaries of what is possible and developing radically lightweight, property optimized structural solutions.” to achieving climate policy goals in vehicle manufacturing, mechanical and plant engineering, energy and the construction industry. Without lightweight design, the possibility of commercially successful products, such as those in electromobili- ty, would become less and less, perhaps rendering them impossible. What is more, successful, safe lightweight design requires comprehensive expertise in reliability and structural durability. In the Lightweight Design area of expertise, LBF is pushing the limits of what taking into account the reliability, sustai- nability and affordability of the technical product solution. Scientists conduct interdisciplinary research and develop solutions, for example, for functionalized polymers, functionally integrated fiber composite systems, mono and multi-mate- rial systems, numeric al and experimen- tal methods of reliability and durability assessment of lightweight solutions, and the use of integrated sensors and actuators for the monitoring and property optimization of structures. 41

MetaVib – Vibro­acoustic metamaterials for reducing noise and vibration New potential lightweight structure for vehicles and machines Fraunhofer project To enable machin- ery and mobility devices to become more economical and sustainable, the components used in them need to be manufactured more efficiently and designed with a more lightweight structure. However, these structures often encounter vibration problems. As part of the “MetaVib” project, vibro-acoustic metamaterials have been researched and developed as an innovative approach to reducing noise and vibration. They offer new free- dom when it comes to designing com- ponents with targeted vibro-acoustic improvements, while also taking into account criteria for a lightweight structure. Currently, vibro-acoustic metamaterials are a topic being researched across the globe in the area of noise and vibration reduction. They can be used to reduce the amplitudes of harmful structure vibrations and noise to such a low level and across such a wide range that would not be possible using conventional measures. They are applied to passive or active local resonators usually arranged periodically on the component to be influenced. The local resonators are tuned into the natural frequency in question and are placed on the basic structure at distances smaller than half the wavelength of the frequency Fraunhofer has developed new concepts and manufacturing technologies for VAMM. to be influenced. “Stop bands”, which are areas where no wave propagation is possi- ble, occur in this frequency range during the transfer function. During the “MetaVib” project, Fraunhofer researchers managed to achieve an effec- tive structure-borne noise reduction of up to 20 dB in defined frequency ranges. This knowledge is provided in a toolbox that facilitates the task of designing and optimizing structures as vibro-acoustic metamaterials at different levels of detail. The design process varies according to the application and supports efficient proto- type development in industrial follow-up projects. VIBRO-ACOUSTIC METAMATERIALS, PASSIVE VIBRATION REDUCTION MEASURES, STRUCTURAL DYNAMICS Lightweight Design Contact Heiko Atzrodt +49 6151 705-349 heiko.atzrodt@ lbf.fraunhofer.de Further information online www.lbf.fraunhofer.de/ metavib-en 43

Further information online www.lbf.fraunhofer.de/ cooperate-en Better life cycle assessment (LCA) and greater sustainability in product development. Strong low CO2 components from fiber­reinforced biopolymers Development of sustainable, durable components for challenging operating conditions Future project Plastic components offer great potential for reducing emissions. As part of the “ COOPERATE” project, Fraunhofer LBF is working with partners to develop methods for fundamentally improving the product design in terms of LCA and sustainability. Combining the replace- ment of petroleum-based plastics with bio-based alternatives and the development of improved methods for designing components favoring a more economical use of materials will cut the CO2 requirement of plastic components by up to 75 % in chal- lenging industrial applications and consumer goods. Improving design processes will boost the potential for a lightweight structure as well as the resource efficiency arising from this downstream. The project partners will then jointly develop design methods that favor a more economical use of materials and bio-based composites to produce durable, heavy­duty components. Specific use cases from the automotive engineering sector are being used as a benchmark. Contact Georg Stoll +49 6151 705-8528 georg.stoll@ lbf.fraunhofer.de Given that bio-based materials achieve a different performance level than tradi tional materials, the climate-neutral substitutes will be developed further in this project, while practical analyses will be conducted on the material properties in light of the structurally important characteristic values. One of the upshots from the project has been new calculation methods that consider the influences of manufac- turing on the quasi-static and dynamic behavior of the materials. The new methods developed and the improved material properties will pave the way for new plastics to be deployed in other technology sectors. SUSTAINABLE, POLYMER, LIGHTWEIGHT DESIGN 45

Future Mobility usage scenarios. New future mobility solutions whether on land, by road or rail; on water or in the air – must function safely and reliably, while, at the same time, being cost­effective and efficient to implement and operate. Yet they must also meet the ever-increasing require- ments in terms of the number of mobility carriers, individualization and sustainabi- lity in the passenger vehicle, commercial vehicle and special vehicle sectors. The consistent focus on a thermoplastic and thermoplastic-based approach has led to questions being asked about suitable lightweight solutions, reliable system design, intelligent structural and monito- ring functions, sustainable materials and even the use of biomaterials. In this context, the Future Mobility area of expertise at Fraunhofer LBF combines the work of the other areas of expertise in relation to their application in mobility solutions, e.g. cyber-physical methods for the validation of new mobility technolo- gies that accompany the development of alternative drive concepts, component- integrated battery systems or innovative ultra-lightweight design solutions. One focus of the work is electromobility, using both battery-electric and fuel cell systems. Pooling expertise for sustainable, connected and autonomous mobility Mobility is undergoing a sustainable trans- formation process. It is increasingly unders- tood as a networked system of different mobility solutions and operator models. The demands on mobile resource efficiency have once again massively increased, not least due to criticism regarding increasing pressures in relation to climate change and the decarbonization required. They make it necessary to develop new drive techno- logies, lighter construction methods and alternative mobility concepts. The progressive electrification of mobile systems, the intermodality of modes of transport and the introduction of increa- singly automated driving functions are an essential building block in the movement toward future mobility, from a technical and organizational perspective. The same applies to the increased use and develop- ment of new small and micro vehicles in the field of private transport, such as pedelecs, cargo bikes, e-scooters – or increasingly drones. The topic of shared mobility also offers technical challenges ranging from smart digital solutions, app developments, and distributed functions to material techno- logy – especially because, in this context, it is necessary to master entirely new 47

Design freeze in place for the eVTOL autonomous freight transport drone. L i g h t h o u s e p r o j e c t ALBACOPTER®: The Fraunhofer­Gesellschaft’s eVTOL lighthouse project Highlight project Fraunhofer is making an important contribution to achieving emission-neutral Urban Air Mobility (UAM) with their develop- ment of eVTOL drones for autonomous freight transport. Fraunhofer LBF is one of the six Fraun- hofer institutes involved. The core tasks at the institute are battery development, aerodynamic design and the construction of the aircraft. In developing a method for designing the structure, the researchers are taking a mission-oriented approach, accounting for requirements in terms of aerodynamics and strength, among other things, during different phases of the flight and for an array of overarching conditions associated with the design and manufacturing processes. The fuselage is designed and constructed to integrate with and adapt to various system com- ponents – this includes the battery and emergency rescue systems, electronics, junction boxes, sensor systems in the fuse- lage and wingtips, and the connection of the engines to the wings via motor support arms. Fraunhofer LBF is leading a subproject on materials and aerodynam- ic structures, combining its own design methods with the manufacturing tech- nologies produced by Fraunhofer ICT. The results of this subject include the creation of a skeletal hull structure made of pul- truded tubular profiles and sustainable, scalable and easily recyclable transport boxes. As part of a subproject on engines, Fraunhofer LBF is developing an energy storage system, thereby contributing significantly to the goal of making the Albacopter fully electric. With this development, the consortium led by the Fraunhofer IVI aims to make a major contribution to an environmentally friendly, flexible and safe future transpor- tation culture. AUTONOMOUS FLYING, LIGHTWEIGHT DESIGN, TRANSPORTATION, THERMOPLASTICS Contact Dr. Saskia Biehl +49 6151 705-282 saskia.biehl@ lbf.fraunhofer.de Dr. Sven Herold +49 6151 705-259 sven.herold@ lbf.fraunhofer.de Further information online www.lbf.fraunhofer.de/ albacopter-en 49

Future Mobility The cyber-physical validation of fuel cell systems at Fraunhofer LBF. Electromobility: Assessing the reliability of hydrogen fuel cells Unique experimental validation environments for hydrogen fuel cell systems Future project Experts expect that hydrogen fuel cell systems will quickly enter widespread use. For this, they must need a reliable and efficient design. The systems’ materials and components, as well as the system itself, must be validated as early as possible during the development pro- cess, in a cost-efficient way that takes operational conditions into account. Further more, it must be possible to conduct the validation without having the entire system manufactured or available. Cyber-physical testing and validation methods could provide the solution here. infrastructure that will supply fuel cell stacks of up to 200 kW; moreover, they will install shakers that work in combina- tion with climate chambers to facilitate vibration studies under environmental conditions, as well as analysis environments for metallic and polymeric materials and components that come into contact with hydrogen. Cyber-physical validation scenar- ios could provide cost­effective and flexible analysis processes for fuel cell systems and their components in the future, thanks their sophisticated combination of experimen tal test environments, model-based simulations and cutting-edge information technology with operational stresses. The establishment of an electrochemical energy supply using hydrogen fuel cells would represent an important system solu- tion for commercial vehicles in the context of transitioning to climate-neutral mobility. At the same time, the fact that these cells are used on a non-stationary basis and thus subjected to multiphysical and chemi- cal stresses means that creating a reliable design presents some special challenges. Fraunhofer LBF is expanding its research facilities to include a hydrogen With the CyPhyFuelCell platform, which involves the cyber-physical validation of fuel cell systems for future mobility appli- cations, the Darmstadt site has gained a unique area of experience and an appli- cation focus that represents an important step toward sustainable mobility. FUEL CELL, HYDROGEN, RELIABILITY AND SAFETY funded by: Contact Dr. Benedict Götz +49 6151 705-8524 benedict.goetz@ lbf.fraunhofer.de Further information online www.lbf.fraunhofer.de/ h2fuelcells 51

Event Highlights The "Forum Plastic Recyclates" discusses how recycled materials are turned into high- performance raw materials. Prof. Rudolf Pfaendner, Chairman Forum Plastic Recyclates 2022 event highlights We can finally meet in person again. Our research teams attended 15 trade shows, and we organized “public discussion panels” and workshops devoted to specific topics on site in Darmstadt. We have also continued with our virtual event formats. 53

O n s i t e a t F r a u n h o f e r L B F Plastic – is it all garbage? Residents of Darmstadt were invited to an open lab event at Fraunhofer LBF On site The visitors learned a lot of new information about “good” plastics. High- lights included the guided tours, short lectures, exhibits and astounding experiments related to recycling and the circular economy. One tangible project result featured at the event was a shopping cart chip made from grass fibers and produced live in the pilot plant. The amount of incorrect or heavily soiled waste in plastic recycling collec- tions means that very little of the plastic inside can be separated by type and go through further processing. As a result, a lot of plastic waste ends up in waste incine- ration plants or is recycled as a substitute fuel. Recycle more plastics, separate waste properly – both young and old participated in activities that produced some valuable tips. Flying the H2 flag Forum Plastic Recyclates Hands-on research One highlight of the event showed plastics’ fun side With this event, we partici- pated in activities celebrat- ing the 25th anniversary of Darmstadt’s title as a city of science – Darmstadt was the first city in Germany to receive this honorary title. On site As part of the GreenMat4H2 high-performance center, Fraunhofer LBF organized regular H2 meet-ups and an OpenLab Day. The aim is to develop new partnerships, particularly within the region, through inspiring lectures, tech- nology presentations and guided tours. More than 300 people took part. Online event The 2022 Plastic Recy- clates Forum, which took place virtually, included its first­ever session dedicated entirely to creating recyclates equivalent to virgin plastics in quality. In order to realize the full potential of recyclates, it is necessary to analyze recyclate streams; Fraunhofer LBF addressed the question of whether analytical fingerprinting could advance the cause of a circular plastics economy. Plastics producers and proces- sors, as well as recyclers and interested parties from the automotive, white goods, construction and packaging user indus- tries, took advantage of this excellent opportunity to update their knowledge. By the way… The 2023 Forum Plastic Recyclates brought together more than 100 in-person participants; planning will soon begin for the March 2024 event in Darmstadt. 55

Structural Durability Structural durability is one of the most powerful means of assessing components and structures in terms of lifetime; as such, it has formed the foundation of our research activities at Fraunhofer LBF since the founding of the institute. We create lightweight design. Reliable.” The mobility industry, as well as mechani- cal and plant engineering and energy technology, all benefit from products that are both light and designed to be safe and reliable for the entire operating and usage phase. Our research and work focuses on designing safe components, assemblies and systems for road and vehicle construction, shipping, aviation, crane construction and wind turbines with a strong focus on practical application and ensuring a long lifetime. Our eight- step block program, developed by Ernst Gaßner, ensures our place in the history of structural durability innovations. Today, we combine cutting-edge numerical, metrological and experimental methods of ensuring structural durability to achieve solutions that meet our high standards of quality and actively incorporate related material science and engineering disci- plines. Our core areas of expertise involve developing methods and procedures for designing structures with a view towards long lifetimes and provable safety and structural integrity. You will find these in successful products, in material and component innovations as well as in processes, such as in additive manu- facturing, for example. Over the course of the digital transformation, these core areas of expertise will be expanded to include powerful tools for cyber-physical simulation and a comprehensive descrip- tion of cyclic material properties from the LCF to the VHCF regime. From materials to complete structures: the departments Materials and Components and Assemblies and Systems specialize in issues pertaining to structural durability, providing you with the answers you need to questions around assessing structural durability of metal materials and compo- nents, developing numerical methods, describing complex kinematics by means of multibody simulation (MBS), construct- ing and verifying suitable models for both components and complete vehicles, and formulating time-accelerated test procedures for laboratory testing. Research Divisions Division Director Structural Durability Dr. Christoph Bleicher +49 6151 705-8359 christoph.bleicher@ lbf.fraunhofer.de www.lbf.fraunhofer.de/ structural-durability 57

Research Divisions Plastics Only cutting-edge products with reliable and rapid access to innovative and high- performance materials can be offered competitively on the world market today. Tailored plastics, plastic additives, plastic composites and plastic processing techno- logies play a central role in meeting high global demands in the areas of mobility, energy, environment, communication, health, nutrition and safety. Plastics enable tremendous savings in resources and energy as well as a wide variety of options in lightweight design. Particularly when they are fiber­reinforced, particle­ filled, foamed or integrated into sandwich structures, plastics can withstand the hig- hest degree of loading and absorb a great deal of energy. They can be supplemented with an additional range of functions such as protection from UV rays and the affects of weathering, reduced fire behavior, functions for the development of special optical properties, electric and thermal conductivity and with sensor and actuator functions. At the same time, increasing demands on sustainability require new solutions in terms of a circular economy and recycling or the development of bioplastics. All components relevant for the implemen- tation of sophisticated plastic applications, running the scope from basic natural science disciplines such as chemistry and physics, material sciences and material technology in processing to expertise in analytics, testing and modeling, are united at a high level under one roof. This is what the following four depart- ments – complementary in their disciplines and methods – “Polymer Processing and Component Design”, “Material Analytics and Characterization”, “Additivation and Durability” and also “Synthesis and For- mulation”, stand for. Division Director Plastics Prof. Dr. Rudolf Pfaendner +49 6151 705-8605 rudolf.pfaendner@ lbf.fraunhofer.de www.lbf.fraunhofer.de/ plastics We develop long-lasting and safe plastics with improved recyclability as well as new technologies for an efficient circular economy.” 59

Management of the Institute Institute Director Prof. Dr. T. Melz tobias.melz@lbf.fraunhofer.de Plastics Staff Sections Prof. Dr. R. Pfaendner +49 6151 705-8605 rudolf.pfaendner@lbf.fraunhofer.de Polymer Processing and Component Design Dr. C. Beinert +49 6151 705-8735 christian.beinert@lbf.fraunhofer.de Material Analytics and Characterization Dr. R. Brüll +49 6151 705-8639 robert.bruell@lbf.fraunhofer.de Additivation and Durability Dr. E. Metzsch-Zilligen +49 6151 705-8609 elke.metzsch-zilligen@lbf.fraunhofer.de Synthesis and Formulation Dr. F. Schönberger +49 6151 705-8705 frank.schoenberger@lbf.fraunhofer.de Associated Department System Reliability, Smart Structures and Machine Acoustics Prof. Dr. T. Melz www.sam.tu-darmstadt.de/en Knowledge Management Prof. Dr. T. Bein +49 6151 705-463 thilo.bein@lbf.fraunhofer.de Strategic Management Dr. S. Biehl +49 6151 705-282 saskia.biehl@lbf.fraunhofer.de Scientific-technical Organization of Operations Dr. K. Burlon +49 6151 705-8899 konrad.burlon@lbf.fraunhofer.de Technology Marketing and Communication H. Hahnenwald +49 6151 705-8330 heiko.hahnenwald@lbf.fraunhofer.de Organizational Development I. Langer +49 6151 705-648 ilona.langer@lbf.fraunhofer.de Occupational Health and Safety R. Wirth +49 6151 705-332 reinhard.wirth@lbf.fraunhofer.de 61

Bremen Hannover Berlin Chemnitz Dortmund Oberhausen Düsseldorf Köln St. Augustin Euskirchen Frankfurt a. M. Wiesbaden Hanau Darmstadt Pfinztal Ettlingen Freiburg München Fraunhofer Netzwerk Simulation Fraunhofer Geschäftsbereich Adaptronik Fraunhofer Netzwerk “Wissenschaft, Kunst und Design” Fraunhofer Forschungsfeld Leichtbau 63