Coupling a compliant structure with a Hand – arm system using FBS

Abstract

The vibrational behavior of a lightweight compliant structure with low damping is strongly influenced by contact with parts of the human body. In this work, a close look is taken at the influence of the hand-arm system in the context of cycling sports. Force transmitted to the hand, along with hand-arm vibration, generates discomfort and sometimes results in injury. Designing structural changes in a given road bike component with the goal of reducing discomfort requires a clear understanding, in this case, of the interaction mechanisms between the hand-arm system and the handlebar (the coupled structure). This paper describes an experimental investigation of this type of interaction between the hands and a handlebar using an FRF Based Substructuring method (FBS) to calculate the resulting dynamic behavior of the coupled structure. The equations supporting the FBS method for this particular application are presented. The compliant structure and the hand-arm system are individually characterized by mechanical mobility Frequency Response Functions (FRF) in the frequency range of 20-400 Hz. Hand mobility is obtained by using the FBS method in a reverse manner. The influence of the hands and the upper body position on hand-arm mechanical mobility is considered. The merits and limitations of using FBS are discussed.