Shape Optimization of a High Performance Motorbike Single Sided Swingarm 2005-01-0887
This work presents the design process of the Ducati Monster S4R single sided swing arm. The casting body and the bushing were joined by a trellis structure: the welding of the pipes produces a suggestive appearance reinforcing the naked style of the motorbike chassis. This shape would also have given the advantage of fast wheel access but would have brought less stiffness than the fork one.
Adopting a numerical-experimental approach, very effective structural actions were undertaken in order to reach the functionality (straight and curve stability, handling) and reliability target on a component with tight technological and aesthetic constraints.
Many virtual simulations were made, changing the truss layout, while at the same time evaluating the contribution of the single pipe to the overall behaviour of the component: the coupled bending-twist stiffness was increased by progressively modifying the swing arm shape.
The most dangerous load conditions due to the Leynì bench test and the motorbike running on the road were applied to the FEM model: the stress field showed the most critical points in the casting body, near the suspension mountings, and in the bend of the casting spread close to the main welding. Therefore some deep ribs were added to the casting body and the welding shape and location were modified. In this way the component strength was considerably improved.
Finally all the numerical calculations were verified through experimental measurements (by means of strain gages and accelerometers) in the bench and street tests.