Experimental investigation of yield and hysteresis behaviour of an epoxy resin under cyclic compression in the large deformation regime

Abstract

High-performance polymers are slowly replacing traditional materials in the automotive and aerospace industries due to their lightness, high strength, flexibility in designing, and ease of processing. Fibres are often used to reinforce the polymers and to increase their mass-normalised mechanical properties. Amorphous polymers such as crosslinked resins or thermosets are often used for composites due to their high mechanical properties over a wide range of temperatures. Polymer matrix composites are expected to stay in service for 10-50 years in structural components, which are often subjected to long-term cyclic loading. To ensure the desired lifetime and safety of these polymer-based components, the timedependent behaviour of polymers needs to be carefully analysed under a variety of cyclic loading conditions. There is extensive experimental literature on the role of viscoelastic and viscoplastic effects on the time-dependent deformation behaviour of polymers [1][2][3][4][5]. Viscous effects include phenomena such as strain rate-dependency, hysteresis, relaxation, and creep. In addition, the progressive accumulation of plastic deformation under cyclic loading accelerates fatigue failure [6,7]. Therefore, knowledge of the cyclic plastic behaviour of polymers is of utmost 133