Experimental set-up for and numerical modelling of bending fatigue experiments on plain woven glass/epoxy composites

In general, fatigue of fibre-reinforced composite materials is a quite complex phenomenon, and a large research effort is being spent on it today. Due to deficiencies in the current life prediction methodologies for these materials, composite structures are often overdesigned: large factors of safety are adopted and extensive prototype-testing is required to allow for an acceptable life time prediction. This paper presents an investigation of the fatigue performance of plain woven glass/epoxy composite materials and of the numerical modelling of these composites' behaviour under fatigue. First, the experimental set-up, which has been developed for bending fatigue experiments, is discussed. The materials used are plain woven glass/epoxy specimens in two configurations: [#0 degrees](8) and [#45 degrees](8). Experiments show that these two specimen types, although being made of the same material, have a quite different damage behaviour and that the stiffness degradation follows a different path. Next, a numerical model is presented which allows one to describe the degradation behaviour of the composite specimen during its fatigue life. This model has been implemented in a mathematical software package (Mathcad(TM)) and proves to be a useful tool to study the fatigue degradation behaviour of composite materials. (C) 2000 Elsevier Science Ltd. All rights reserved.