Abstract
KEYWORDS –Vibro-Acoustics; Stamping Effect; Sheet Metal Component; Thickness change; Incremental Method
ABSTRACT – This paper presents a vibro-acoustic study on stamping effects affecting to structure-borne noise of a passenger car. A conventional automotive body structure is a type of Monocoque which consists of lots of sheet metal panels. Those thin-walled structures are mainly manufactured through stamping processes. In CAE analysis, the sheet metal components are modeled at a nominal state with uniform thickness and no residual stresses and strains. However, in reality these components are manufactured by sheet metal forming process that introduces non-uniform strain hardening and changes in thickness distribution over the sheet components. Sheet metal components of a body structure are simulated through hot/cold stamping processes. Once the thickness change, residual stress and residual strain after the stamping processes are identified over the panels, those data are mapped into the finite element models of the vibro-acoustic simulation model. And then, the modal frequencies and vibro-acoustic transfer functions are estimated and compared to test measurements. Then it is validated that those vibro-acoustic results become correlated better than the case without the stamping effects. In addition, while we study on the stamping effect, we check the stamping algorithms, inverse and incremental methods to generate better correlation. It is interesting to mention some finding in which a vibration calculation with the stamping result using the incremental method improves the correlation in terms of not only weight but also modal frequencies and the level of FRF curves. This study has been done with major stamping effects such as thickness change and residual stress but without any spring back. In this study, very promising results are obtained with the proposed approach, “Vibro-acoustics due to stamping effects with an incremental method”, which offers very good prospects in view of the NVH correlation challenges.