Effect of Seat Support Structure Stiffness on Handling of Motorcycles

Dynamic behavior of motorcycle is influenced by several parameters, which derive from various subsystems that go into making a motorcycle assembly and the way they are integrated. Structural stiffness has been a key consideration by most of the dynamics engineers, in design and tuning of motorcycle dynamics. Different approaches have been used in the study of structural stiffness effect, like lumped mass model, distributed stiffness model, static stiffness and dynamic stiffness. A limited research has been done on the effect of carrier luggage supported at rear end of the frame on steering oscillations. The authors of this paper found that the effect of significant changes in the parametric values of seat structure stiffness is not captured vividly in typical mathematical models available so far, whereas the experimental bikes built with such changes demonstrate substantial change in the dynamic behavior, quantified by both expert rider’s feel as well as objective measurements.

In this study the effect of seat support structure stiffness on motorcycle stability is studied under various loading conditions using simulation and testing. The vehicle behavior is tested with different dead weights on seat support structure. The stiffness and natural frequency of the structure is estimated using Finite element analysis. The simulation results are validated using experimental testing. The stiffness and natural frequency of the structure is improved using FEA. A proto has been made with increased stiffness and is tested at various speeds to understand the effect of stiffness and carrier mass on vehicle stability.