Energy dissipation in human hand-arm exposed to random vibration.

The problem of correlating the incidence of Raynaud’s phenomenon with exposure to a given vibration environment is well known. It is hypothesized that energy absorbed and dissipated in the hand is energy which can change hand tissue in some manner, and thus may cause injury. Absorbed power is therefore suggested as a parameter which has potential for evaluation of individual worker susceptibility to vibration injury. The arm is represented as a foundation with finite mechanical impedance for the hand model. The hand model parameters, obtainable from experimental impedance measurements on individual subjects, are assumed to be, in general, frequency dependent. The total impedance expression for the system is generalized for the case where the hand is gripping a vibrating handle covered with a layer of viscoelastic material. An expression for absorbed power in this composite system exposed to random vibration is presented.Subject Classification: [43]40.45.