Finite element model development and result comparison for human hand-arm vibration

The usage of vibrating power tools for extended lengths of time has been proven to have harmful effects to the human hand-arm system (HAS). The outcome of this interaction can lead to mild to severe discomfort to the user, which can result from vibration-induced disorders. It is therefore necessary to reduce the vibrations transmitted to the system and discover the mechanism and kinds of vibration inputs to the system that cause damage. Much research has been done to determine the potential risk as well as the mechanism of injury given certain inputs, but still there is no precise mechanism in place to understand how injury takes place.

A finite element (FE) model of the HAS was established in this study to better estimate the vibration transmissibility response of the system; a harmonic input is applied to the palm and the responses of the fingers, wrist, forearm, and upper arm are separately recorded. The FE model is developed for a 90° “bent arm” and a 180° “extended arm” posture, and three cases are considered where the input displacement load is applied for amplitudes of 1mm, 5mm, and 10mm. Lumped mass HAS models are also employed to validate the results of the FE model by comparing the vibration transmissibility response results of both models. The results of the FE model reveal good agreements for the palm-wrist, forearm, and upper arm, but poor agreement for the fingers.