Study of progressive damage in a knitted fabric reinforced composite

Model sandwich laminates were manufactured by orienting the knitted cloth at a range of angles to the loading direction using a single Milano weft knitted layer sandwiched between outer plies of unidirectional glass reinforced epoxy resin in order to be able to observe progressive damage accumulation along the sample. By this way, the relationship between fibre architecture and damage accumulation under tensile loading, as well as the sequence of damage accumulation has been investigated. Damage has been found to initiate at the loop cross-over points of the knitted fabric structure for all orientations, although the further development of the damage depends on the orientation of the fabric to the applied load. The resultant transparent laminates provide a novel method of monitoring the damage development in a knitted-fabric composite as a function of increasing strain by allowing direct observation of the sequence of damage