Design sensitivity analysis of noise, vibration, and harshness of vehicle body structure

A continuum design sensitivity analysis (DSA) approach to noise, vibration, and harshness (NVH) of vehicle body structure is developed using Mindlin plate and Timoshenko beam theories. Linear shape functions used for numerical methods of DSA cause a deficiency in bending energy that is accounted for. For large scale NVH applications, linear and bilinear isoparametric elements require much less analysis time. To handle complex vehicle built-up structures, the warped plate element and general cross-sectional beam element with offset effects are included in the numerical method for DSA. A variational approach is used to obtain the continuum design sensitivity formulation. Thickness of plates and nonprincipal section parameters of beams are selected as design variables. A numerical implementation method for continuum DSA is developed by postprocessing analysis results from established finite element analysis (FEA) codes to obtain NVH design sensitivity. The numerical method is tested using large-sc-ale concept and detailed passenger vehicle models. Design sensitivity results are validated using reanalysis results.