Press releases

Increasingly stringent statutory emission limits are pushing the automotive industry toward innovative lightweight design solutions. In this context, the fatigue strength of thin sheet metal structures, especially made from multi-material, is becoming increasingly important. As part of the EU-funded research project "ALLIANCE" on the topic of lightweight design and CO2 reduction, the car manufacturer Opel Automobile GmbH, together with the Fraunhofer Institute for Structural Durability and System Reliability LBF and the System Reliability, Adaptive Structures, and Machine Acoustics department of the Technical University of Darmstadt, has developed innovative numerical fatigue strength assessment approaches for multi-material joints based on fatigue tests of hybrid joined shear and peel specimens. The method was validated by Fraunhofer LBF scientists with fatigue tests on component-like bowl specimens with the material pairing Steel-Aluminum.

For quality control and damage assessment of injection-moulded components, simple and cost-effective tests are desired. Preparation of the standard test specimens is sometimes costly. In this case, the specimens taken from the flat areas of the component can be preferred. Scientists at the Fraunhofer Institute for Structural Durability and System Reliability LBF have improved known in-plane geometry for the shear test. Together with the modified loading schema, the new procedure is reliable and can be used for a wide range of materials. The new test specification is especially developed for SME's to reduce the costs of the component development and also by quality control. With this method, the data for material appropriate modelling can be obtained. The manufacture of special test specimens is obsolete.

Components are subject to multi-axial loadings. The typical design approach is based on material specific modelling and suitable tests to identify the parameters of the model. The tests are costly and time consuming. Scientists at the Fraunhofer Institute for Structural Durability and System Reliability LBF have suggested a basic approach to select the necessary tests for reliable modelling.

Fraunhofer Institute for Structural Durability and System Reliability LBF have taken a closer look in an attempt to answer this question. The initial situation: larvae of the wax moth Galleria melonella are thought to eat and digest polyethylene, which is why they are considered to contribute to the CO2-neutral elimination of the mountains of plastic waste that are growing worldwide. However, whether the caterpillar can do this is still not understood and is currently the subject of controversial discussion. Within the framework of a research project on the chemical imaging analysis of plastic digestion in caterpillars (RauPE), a team from Fraunhofer LBF used high-resolution Raman microscopy and dedicated software to follow the path of the plastic through the caterpillar and made important contributions to clarifying these unanswered questions.

Plastics behave dependent on temperature and strain rate. When designing components, it is therefore important to know the behavior of the plastic used, not only under laboratory conditions, but also under the subsequent conditions of use. The entire spectrum of possible temperatures must be considered. To this end, scientists at the Fraunhofer Institute for Structural Durability and System Reliability LBF have expanded the dynamic possibilities at the institute's own modified high-speed testing machine with a device that enables plastics to be examined even at low temperatures – validated down to -40 degrees Celsius – without a thermal chamber. dynamischen Testmöglichkeiten am institutseigenen Schnellzerreißer mit einer Vorrichtung erweitert, die es ermöglicht, Kunststoffe auch bei tiefen Temperaturen – validiert sind bis -40 Grad Celsius – ohne Thermokammer zu prüfen.

Since 2002, the Fraunhofer Institute for Structural Durability and System Reliability LBF has been granting the Ernst Gaßner Award for outstanding achievements in structural durability. The award honors experts for exceptional contributions in the development of safety-relevant, reliable lightweight components. This year, the seventh award ceremony saw the Darmstadt-based institute honor two winners: Dr. Yung-Li Lee, Fiat Chrysler Automobiles N.V. (FCA) in Auburn Hills, MI-USA, and Bruno Seufert, Daimler AG in Sindelfingen, Germany.

“Infusion 4.0,” a project funded by the Federal Ministry of Economics and Energy, shows how effective fiber-optic sensors are in monitoring the vacuum infusion process during the production of large composite components. Together with its project partner, MT Aerospace AG, the Fraunhofer Institute for Structural Durability and System Reliability LBF has made the previously-hidden process steps visible and digitally controllable, thereby increasing process reliability. This new, efficient manufacturing technology supports reliable and fast development of aerospace products.

Ultra-high-strength aluminium alloys are the future of lightweight construction in conventional and e-mobility. The Fraunhofer Institute for Structural Durability and System Reliability (LBF) and its research partners are developing resource-optimized process technologies within the framework of ALLEGRO, the central project of LOEWE – Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz (State Offensive for the Development of Scientifically Economic Excellence), with which local component properties can be adjusted to meet future requirements. The scientists evaluate the entire process chain in order to optimize it economically and ecologically and to enable a more sustainable product design.

Many modern plastic materials do not come without added flame protection. When developing new plastic compositions of this kind, the aim is to achieve an optimum combination of flame retardancy, processability and mechanical properties. Scientists from the Fraunhofer Institute for Structural Durability and System Reliability LBF and the Bundesanstalt für Materialforschung und – prüfung (BAM) have demonstrated how this objective can be achieved more quickly. The researchers are proposing both accelerated procedures in processing and in the characterisation of fire behaviour. The numerous investigations within the scope of the research project entitled ‘Rapid Development of Flame Retarded Thermoplastic Polyurethane’ have generated valuable data. A particular application of these data is for medium-sized businesses to optimise their already existing or the development of new flameretardant formulations in the future. The results of the project thus contribute to safe products on the market. Fraunhofer LBF will be presenting more about flame retardants at the "K" trade fair from October 16 to 23, 2019 at Plastics Europe in Hall 7 SC 09.

Numerical simulations have massively accelerated product development over the past few decades. A variety of scenarios can be tested in a short time and the number of necessary prototypes has been steadily reduced. Nevertheless, physical tests are widespread and will not lose significance over the next few decades. Numerical models must be validated and approval testing must be carried out. Depending on the modeling complexity, the physical test can also be more cost-efficient. In the recently completed project “Digitization in Testing Technology”, scientists from the Fraunhofer Institute for Structural Durability and System Reliability LBF addressed the question of how physical testing can benefit from methods from the numerical world. What is the optimal combination of real and virtual world? Tunable test rig components and a mechanical hardware-in-the-loop approach have been developed. They make it possible for mechanical parameters such as stiffness rubber mount properties and structural dynamic effects to be set quickly and without modifications to the test rig. This facilitates rapid parameter variations to the test rig and further provides a new, energy-efficient interface between numerical real-time simulation and testing bench. The Fraunhofer LBF will present the results at the Automotive Testing Expo in Stuttgart from May 21-23, 2019 in hall 8, booth 8052.