Non-destructive inspection of sandwich and repaired composite laminated structures

A cost and time effective inspection strategy for in-service health monitoring of composites is demonstrated using the fundamental anti-symmetric A0 Lamb mode at frequencies of 15–20 kHz. In principle, this method involves analysis of the transmitted and/or reflected wave generated by a piezoelectric device after interacting with the test-piece boundaries or discontinuities (defects). In the present work, the applicability of the technique to inspect sandwich and repaired composite laminated carbon fibre reinforced structures is explored.