Design Optimization of Frame Stiffness through Hydroforming

Two wheelers are very popular as means of transportation in ASIA. Chassis is a very critical part of a two wheeler taking most of the loads coming from the roads. During the design and development stage, stiffness of the frame needs to be established. Stiffness is one of the critical parameter, which decides the handling performance of the vehicle. Conventionally, the main tube of motorcycle frame will be of uniform cross section throughout the axis of the tube. Variable thickness cannot be achieved in this method. In the new process called hydro forming, variable sections can be achieved. FE analysis has been done on the frame and the stresses are predicted. The stress pattern helped in identifying the critical areas. The critical areas identified are validated through experimental strain measurement. The validated model is further used to optimize the design by reducing the stresses at critical areas to below the acceptable limit & improving the stiffness values. The final optimized frame cleared the structural & handling tests without any failure. With this method, we were able to improve the stiffness to weight ratio.