Use of PVDF as acoustic emission sensor for in situ monitoring of mechanical behaviour of glass/epoxy laminates

Structural health monitoring (SHM) and in situ monitoring of structural integrity are of primary importance in many engineering fields such as automotive, aerospace and complex civil structures. Furthermore, the ever growing use of composite materials has raised the need for reliable and cost-effective health monitoring systems. This work presents an experimental investigation of a piezopolymeric based in situ damage detection technique based on acoustic emission (AE) with poly(vinylidene fluoride) (PVDF) sensors as AE sensors. These sensors have been surface-mounted and embedded in glass/epoxy laminates and used to monitor the laminates while being subjected to three types of loading, namely tension, three-point bending and post-impact three-point bending. A parametric off-line analysis of signals detected and scanning electron microscopy (SEM) analysis allowed assessing the ability of PVDFs to monitor the damage growth and development in these laminates. The results confirm that PVDFs can be applied in real time monitoring studies of composite laminates.