Dynamic Stiffness Investigation of an Automotive Body-in-White by Utilizing Response Surface Methodology

Abstract

Noise, vibration, and harshness (NVH) attribute is needed to be included in the vehicle structure design since improving the NVH characteristics enhances the ride quality experienced by the occupants. In this regard, an efficient method was proposed to investigate the structural dynamic response of an automotive body considering low-frequency NVH performances. Moreover, the improvement of an automotive structure under the constraint of NVH behavior was investigated by using the design of experiments (DOEs) method. The DOEs methodology was for screening of the design space and generating approximation models. Here, the thicknesses of panels consisting of a body-in-white (BIW) of an automotive were employed as design variables for optimization, whose objective was to increase the first torsional and bending natural frequencies. Central composite design (CCD) for DOEs sampling and response surface methodology (RSM) were employed to optimize the dynamic stiffness. Moreover, the effects of the selected variables as well as their binary interactions were modeled and the optimum conditions for rigidity improvement were obtained via the RSM. Furthermore, the validity of the proposed optimization scheme was verified through CAE analysis. The results indicated that the first torsion and bending natural frequency were improved compared to the baseline design. Additionally, precise surrogate models in polynomial terms for the first bending and torsion natural frequencies were obtained.