Effects of rear axle with tubular V-formed twistbeam on weight reduction and finite element analysis

Movement of vehicles used in passenger transportation on the ground is provided with rubber tires. However technology on cars continues to be developed, rubber tires will be used for a long time in the automotive industry. Rubber tires play a significant role on vehicle dynamics. The performance of vehicle is dependent on two basic factors. The prior is engine force to drive and the second is handling situation of tires on the ground. This is why so tire forces from the ground is important to determine vehicle dynamics conditions. Although rubber tires have flexible structures, they highly transmit the disturbing effects from the road to vehicle body. For this reason, the suspension systems which consists of shock absorbers and springs are usually preferred to meet the comfort requirements of driver and passengers. If stiffness of suspension decrease, comfort increase; on the other hand handling of vehicle will decrease. Also this situation is reversible. Optimum way is founded to meet the both comfort and handling requirements. Automotive industry focuses on the weight reduction for vehicle components in terms of the compliance with new legal requirements and reduction of greenhouse gas effect. At the same time, manufacturers study on new concept designs, processes and new generation materials without compromising the safety of the vehicle components. Suspension system is one of the most significant product on vehicles for weight reduction. This thesis mainly concerns critical design parameters of a semi-independent rear axle suspension system with a V-formed tube for a passenger car. Firstly, it is described what types of rear axles are and which components of suspension systems. Many types of passenger cars are benchmarked in terms of their rear axle suspension types. According to the twist beam theory, a V-formed tube structure is designed considering the benchmark study. The rear axle with V-formed tube, designed for the passenger car, is modelled as finite elements using Hypermesh. The forming analysis of V-formed tube is performed with Hyperform, structural analysis of the system is solved via Optistruct and Adams is used for the dynamic analysis. After correlating FEA results, critical zones on the rear axle system are pointed out. Solutions are offered for these zones investigating the results. Additionally, the V-formed tubular rear axle is compared with a sheet-formed rear axle structure with an anti-roll bar, advantages and disadvantages of the tubular rear axle are identified for weight reduction.