CrashOpt - Development of a Material Model for Lateral Composite Crash Absorbers

Mechanical Characterization & Modeling5News1News25

In case of a crash, fiber-reinforced plastic composites can absorb large amounts of energy at a low weight under a suitable load. This property makes them very interesting for applications in the mobility sector, such as crash absorbers in automobiles. For this purpose, the structure must absorb the necessary energy but must not behave too stiffly to avoid high decelerations that could be dangerous for the occupants. These boundary conditions make it essential to optimize the design for the dynamic crash case. Due to their anisotropic behavior and their own specific failure modes, the calculation and design of fiber-reinforced plastic composites already pose a significant challenge to the calculation methods used in the static case. This is particularly evident when using structural optimization methods as the calculation must be used to distinguish between promising designs and inferior designs reliably. In optimizing crash- or dynamically loaded structures, the calculation becomes even more challenging due to the nonlinear behavior of these structures in almost all areas. Thus, classical optimization methods can only be used to a limited extent. Instead, experience-based, heuristic methods represent a promising alternative since they can better deal with strong nonlinearities.

In this research project, based on quasi-static and crash tests, a simulation methodology and a material model are developed, which is suitable for the heuristic structural optimization of carbon fiber reinforced thermoplastic multi-chamber profiles using the simulation software LS-DYNA. Leibniz-Institut für Verbundwerkstoffe and the department chair Optimization of Mechanical Structures (OMS) of Wuppertal University are collaborating within this project. Developing a suitable optimization strategy and its implementation is being pursued at OMS. The profiles created this way will be manufactured using a laser tape-laying process, and their crash behavior will be validated with a final simulation. For example, the optimized profile structures could be used as side sills in a vehicle door.

The project "CrashOpt - Development of an optimization-oriented material model for the automated topology and shape determination of crash structures made of thermoplastic fiber-plastic composites" is funded by the German Research Foundation (DFG) - SCHM 2726/4-1.

Experiment on a CFRP-multi-chamber profile under lateral load

Simulation model of the heuristically optimized multi chamber profile for 3 point bending



Sebastian Schmeer

Deputy Research Manager Component Development & Manager Mechanical Characterization & Modeling

Special Expertise: Mechanical characterization of materials, components and joints (strain rate & temperature variable), DIN/ISO standardization, material behavior under multi-axiality (tension/compression and torsion), FEM simulation (mechanical), material model parameterization, validation of FE simulation models by experimental investigations, structural integrity, metal-fiber reinforced composites

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