Vehicle Restraint System Optimization and Robustness Assessment using the Coupling between LS-DYNA, LS-OPT and DEP MeshWorks Software

Road safety structures are CE (European Commission) marked safety systems which need to be crash tested. Structure performances during the crash tests and the associated rating have a significant marketing impact for the system manufacturer and unfortunately depend on parameters subjected to stochastic variation (raw material mechanical properties, test conditions, vehicle design, …). Numerical simulation has been widely used for several decades to assist in the design of these new road safety devices. Historically, in order to identify a design likely to pass the experimental tests, simulation has mostly been used without taking into account the variability of the modelled system parameters but only its nominal design. However, in too many cases, the great variability of such devices (materials characteristics, ground type, assembly conditions, impact parameters, etc…) leads to unexpected behaviour (and results) and jeopardizes the test validation. In the following sections the full process of one road safety system optimization will be presented starting with the correlation between the numerical model results and the corresponding real crash test results. Then, a design optimization on a reduced model will be performed using an innovative approach based on an advanced use of the DEP MeshWorks morphing capabilities coupled with LS-OPT© and LS-DYNA©. Finally, based on the optimal design found previously, an additional sensitivity study using LS-OPT and LS-DYNA will be conducted to better assess the device robustness and its sensitivity to material characteristics changes. The aim is to enable designers of new systems to better assess the risk of failure when performing the experimental tests required by the standard.