Impact Damage Detection and Assessment in Composite Panels using Macro Fibre Composites Transducers

Structural health monitoring of composite components is vital to the use of these materials in aerospace applications. Being highly susceptible to impact damage, composite materials can sustain internal damage that is very difficult to detect externally. This paper explores the use of macro fibre composite (MFC) transducers not only to detect acoustic emission (AE) released during the impact event but also as pulse/receivers to further quantify damage. To assess the dual functionality of these transducers, two were adhered to a composite panel and subjected to a number of impacts. A commercial AE system recorded signals during the impact event. After each impact, signals were pulsed and received between the two transducers and a C-scan inspection of the panel was conducted to assess the extent of the damage. Post test analysis demonstrated a clear correlation between the AE signal energy and the increase in delamination size. Furthermore, a cross correlation technique was utilised to compare signals in the undamaged plate with those at varying damage levels. The results demonstrated a decreasing correlation of signals with increasing damage severity. The results have shown that MFC transducers offer a real possibility for identifying and sizing impact damage in composite structures.