More reality in virtual crash tests

Crash Safety, Damage Mechanics

We develop and implement material and failure models and utilize them in crash and process simulations. We also use special testing techniques (e.g. local strain measurements, torsion and biaxial tensile tests) to characterize materials and test components. By simulating various trials, we determine the model parameters and validate the practicability of new numerical methods. The effects of manufacturing processes on component behavior are paid particular attention.


Characterization of deformation and failure behavior under different types of load

Component trials under realistic loads

Development and verification of material models and numerical methods for crash and process simulations

Failure modeling that is consistent in both crash simulations and forming/casting simulations

Simulation of aluminum profile extrusion with microstructural calculations

LFT crash simulations linked to form filling simulations

Assessment of the crash safety of battery housings



Material and component deformation and failure behavior


The characterization of a material’s deformation and failure behavior sets the foundation for reliable design and numerical simulations. At the IWM, we perform specialized tests that subject the sample to tensile, compressive and shear stresses in order to determine the effects of multi-axiality and load type on failure behavior. Component tests at up to 8 MN can be carried out to validate simulations... 


Failure models for crash simulations


The Fraunhofer IWM has developed material models that accurately describe the deformation and failure behavior of new materials and are integrated into commercial crash codes as user material routines. For example, our damage models and phenomenological models, which account for “honeycomb” and shear fracture, can be used to model micromechanical failure. We have also developed and implemented pressure-related material models that ...




Modeling the failure behavior of long fiber thermoplastics (LFT)


The behavior of LFT components can be easily predicted thanks to the combination of mold filling and crash simulations. The simulation accounts for the distribution of fiber orientation and fiber thickness. The material model is based on homogenization methods. The first step is to approximate the unidirectional properties of the composite with a transversally isotropic rigidity matrix. Empirical methods are used to implement damage development. The second step ...




Crash simulations 


Crash simulations are performed in order to assess the crash safety of various components and validate the applied material models; the results are compared to those of component trials. The commercial PAM-CRASH, LS-DYNA and ABAQUS crash codes are often combined with user material models. In order to account for the effects of manufacturing processes on crash behavior, one can, for example, transfer pre-stretching and previous damage from deep drawing simulations or porosity from ...




Publications regarding Crash Safety, Damage Mechanics

Contributions to newspapers, books and conferences as well as dissertations and project reports...