Visualisation of barely visible impact damage in polymer matrix composites using an optical deformation and strain measurement system (ODSMS)

This study deals with damage evaluation using an Optical Deformation and Strain Measurement System (ODSMS). Damage was introduced using an Instrumented Falling Weight Impact Test (IFWIT) machine. The incident impact energy was controlled to low magnitude so that the specimen was not penetrated and only internal or barely visible damage was introduced. This damage can have an adverse effect on structural integrity, and potentially lead to catastrophic failure. It is important to identify the damage and assess the structural integrity of components made of composites non-destructively. This paper presents the theoretical aspects involved in ODSMS and its capability of evaluating the impact induced internal damage. It has been found that ODSMS can successfully identify the internal damage in terms the strain concentrations at different loading levels. The damage location and geometrical characteristics are in good agreement with those evaluated by conventional NDT techniques.