Redesign, modal analysis and stress analysis of cross car beam

As components of the car's dashboard, there is a support structure which is called cross-car beam (CCB). This beam bears the loads and respond to crash forces. Cross-car beam is essential, because its functions include safety, structural support of the instrument panel and passing sound, vibration and harshness (NVH) standards. If the natural frequencies of the cross-car beam overlap with one of the excitement frequencies, a phenomenon known as resonance occurs. According to the low stiffness of the cross-car beam, the modal response of the cross-car beam should be studied and modified to avoid this destructive phenomenon. In this article, by changing the material of the cross-car beam from steel to polymer-based composite, the beam was redesigned and its vibration performance and stress analysis were performed. The simulations showed that changing the material of the metal beam to glass-epoxy composite, carbon-epoxy composite and fiber in metal laminate (FML) increased the natural frequency by 18%. In order to avoid resonance, more increasing is required for natural frequency amount. Therefore, several supports were added to connect beam to car body and reduce degree of freedom. Changing the material and increasing supports at the same time resulted 460% increasing for natural frequency. Because excessive increase of natural frequency will lead to increasing structure rigidity and as a result stress concentration, so numerical stress analysis was done and finally a suitable laminated composite was suggested for cross-car beam.