Methodology for parameter identification on a thermoplastic composite crash absorber by the Sequential Response Surface Method and Efficient Global Optimization

Numerical simulations for crashworthiness require the definition of material properties that are not always pre-dictable with standard experimental tests. This paper deals with the numerical optimization of a thermoplastic com-posite material model. The component is a vehicle impact attenuator made of an innovative All-PP (PolyPropylene)composite material. The peculiar failure mechanism of this material makes the numerical simulation of the collapsea difficult challenge to achieve with a trial-and-error calibration of the material card. Therefore, an optimization pro-cedure is proposed to determine the material parameters. The optimization is implemented in LS-OPT, where themean square error between the experimental and numerical load-displacement curves is the objective function to beminimized. Two test cases are considered: (1) optimization of the material card based on the full load-displacementcurve from the experimental tests and (2) optimization of relevant parameters of a numerical trigger added to controlinitial contact instabilities between the impacting rigid wall and the component in the numerical simulations. Theoptimization strategies Sequential Response Surface Method (SRSM) and Efficient Global Optimization (EGO) areused. The results show that the presented methodology allows characterizing the studied composite material and thusobtaining a more efficient numerical model.