Fatigue degradation modelling of plain woven glass/epoxy composites

Due to their anisotropic and inhomogeneous nature, the fatigue behaviour of fibre-reinforced composite materials is complicated and since many years a large research effort is being spent on this problem. Despite these efforts, fatigue design of fibre-reinforced composites still has to rely mostly on expensive time-consuming fatigue experiments and large safety factors have to be adopted. In this paper, a combined experimental/numerical investigation of the fatigue behaviour of plain woven glass/epoxy composites is presented. Bending fatigue tests were used to yield the experimental data. With the aid of an advanced phase-shift shadow Moire technique, an out-of-plane displacement profile during fatigue life of the composite specimens was recorded at a number of intervals, as well as the bending force history. A residual stiffness model, which describes the fatigue damage behaviour of the composite material, was adopted. Next, a new finite element approach was developed to implement the fatigue damage model in a commercial finite element code that proves to be capable of simulating the observed experimental results. (C) 2001 Elsevier Science Ltd. All rights reserved.