Sensitivity analysis of complex engineering systems: Approaches study and their application to vehicle restraint system crash simulation

•Sensitivity Analysis helps to identify the key factors concerning the robustness.•SA of Vehicle Restraint Systems is a way enhance the robustness of the design.•Certification of VRS based on very few crash tests is quite unsatisfactory.•The two most influential parameters are the post thickness and post yield strength.•Combining numerical studies and SA is a way to improve regulations. Restricted by high calculation cost of single engineering model run and large number of model runs for sampling-based Sensitivity Analysis (SA), qualitative SA are used for parameter study of the Vehicle Restraint System (VRS) and quantitative SA of such models has always been a challenge. Sequential approaches are proposed for SA of complex systems and the SA of a VRS is realized: sampling-based SA methods are discussed; SA of a simple three points dynamic bending test model is realized, the aims are to compare different two-level screening methods and put into practice the sequential SA; crash test FE model of a VRS is created and used for SA; influential uncertain parameters of the VRS are identified qualitatively through screening analyses (SA with Two-level screening and Morris Analysis), and Sobol’ indices are used to quantify the influence of influential parameters with Kriging metamodeling. The uncertain parameters which contribute the most to robustness of the VRS are identified and their influences are quantified by combining screening analyses and Sobol’ Indices.