Numerical Investigation of Cross Car Beam using Magnesium Alloy for Weight Reduction

The fuel efficiency requirements set by the regulations have made to look for lighter materials like Aluminium (Al) and Magnesium (Mg) instead of Steel. Cross Car Beam (CCB) is a structural member made up of steel which can be replaced by Mg or other lighter materials to reduce the overall weight of the vehicle. CCB is a structural member between A pillars which holds the steering and HVAC units. Numerical investigations are carried out on Mg CCB to meet the structural requirements of existing CCB. Mg is 73% lighter than steel and 34% lighter than Al. In this work, base line analysis is carried out on existing CCB to arrive at the frequency, stress and deformation patterns. Geometric modelling of CCB has been carried out with CATIA and frequency response and static structural analysis of the component have been carried out using Ansys Workbench. The modal analysis has validated by carrying out experimental studies on the existing CCB. Design modifications are carried out on Mg CCB to meet the frequency response and structural characteristics of CCB. It is observed that Mg can replace steel, since the first lateral and vertical frequencies are above 100 Hz and is in the safe zone. The weight of CCB has reduced from 5.8kg to 1.56 kg in Mg leading to 70% weight reduction.