GRIP PRESSURE DISTRIBUTION UNDER STATIC AND DYNAMIC LOADING

The dynamic response of a vibrating hand-arm system is strongly relate d to the grip force. While the relationship between total grip force a nd vibration characteristics of the hand-arm system has been extensive ly studied, no attempts have been made to investigate the distribution of grip pressure at the hand-handle interface. The local grip-pressur e distribution may be more closely related to the finger blood flow, f atigue and loss of productivity than total grip force. In the present study, distribution of static and dynamic forces at a hand-handle inte rface is investigated using a grid of pressure sensors mounted on the handle. The pressure distribution is acquired for different values of static and dynamic grip forces in the range of 25-150 N. The dynamic m easurements were conducted at various discrete frequencies in the 20-1 000 Hz range with peak acceleration levels of 0.5 g, 1.0 g, 2.0 g and 3.0 g. The grip-pressure distribution under static loads revealed a c oncentration of high pressures near the tips of the index and middle f ingers, and the base of the thumb. This concentration of high pressure s shifted towards the middle of the fingers under dynamic loads, irres pective of grip force, excitation frequency and acceleration levels. T hese local pressure peaks may be related to impairment of blood flow t o finger tips and the possible causation of vibration white finger.