Detection of Impact Damage in Thermoplastic-Based Glass Fiber Composites Using Embedded Optical Fiber Sensors

Step-index multi-mode optical fibers have been embedded in a thermoplastic glass fiber polypropylene (GF/PP). Three types of commercially available optical fibers have been investigated to evaluate their potential for detecting impact-induced damage in thermoplastic-based composite structures. Preliminary findings have confirmed the feasibility of using these inexpensive multi-mode optical fibers as damage sensors in high-performance composite materials. When embedded between the uppermost ply of a cross-ply unidirectional [0/90](sub s) laminate, impact energies as low as 0.8 J have been detected using these optical fibers. The optical fibers have been embedded at different locations within the composite structure to investigate the effect of embedment locations on their sensitivity for detecting impact loading and damage.