An experimental technique for determining biaxial fatigue lifetimes in biomedical elastomers

A novel test apparatus was developed to determine fatigue lifetimes of elas tomeric materials. Thin elastomeric sheets (membranes) are biaxially fatigu ed while contained within a temperature controlled liquid environment. Memb ranes are displaced in a smooth sinusoidal motion by pumping the surroundin g fluid through the equipment's inner cells. An electrical signal (AC) pass es through the membrane during fatigue and is used to monitor changes in th e elastomer's physical characteristics. In addition, the test cell is desig ned to allow optical observation of the membrane throughout the fatiguing p rocess. Thus the design results in a test rig apparatus that permits failur e determination by both material property changes and obvious fracture. Cyc lic fatigue frequencies range from 0.2 to 1.2 Hz. (C) 2001 Elsevier Science Ltd. All rights reserved.