An Investigation Of Human Palmar Skin Friction And The Effects Of Materials, Pinch Force And Moisture

A study was conducted to determine the friction characteristics for various materials against human palmar skin. Seven materials were tested using two pinch-force levels under both moist and dry conditions. Using a two-fingered pinch grip, subjects held a specially designed dynamometer covered with one of the test materials. They maintained a constant pinch force as load force was increased at a constant rate until the dynamometer slipped from their fingers. The load force at the slip point was then used to determine the coefficient of friction from Amonton's Law. The effects of subject, material, moisture, pinch force and the material-moisture and pinch force-moisture interactions were all significant. The coefficient of friction decreased with increased levels of pinch force for every material-moisture combination. The coefficient of friction for porous materials showed a significant increase when moisture was present. This information may be applicable in tool handle and work station surface design.