Detection of surface cracks in fibre reinforced composites using ultrasonic Rayleigh waves

The use of ultrasound to detect defects in fibre reinforced composites (FRCs) is challenging due to the conflicting need to use high frequencies for adequate resolution, but simultaneously ensure adequate wave propagation in the material despite scattering from the fibres. This paper explores the use of Rayleigh surface waves in order to detect exterior cracks in a glass FRC rod. These surface waves are excellent at detecting surface cracks and are conveniently identified when immersed via energy leakage. Finite Element Analysis (FEA) models are used to simulate the propagation of a Rayleigh wave and the effect of surface cracks on this propagation. Experimental studies on glass and a composite material are then used to investigate the applicability of Rayleigh waves to detecting surface cracks.