Damage detection in composite under in-plane load using tap test

This paper presents an approach to detect damage in composite laminates. The physical basis of the coin-tap method has been investigated in previous studies. The tap test has the ability to indicate damage such as delamination and disbond in a composite structure due to a localized change of stiffness. The changes in vibration signature may be detected by ears or more precisely by measurement instrumentation. It has been shown that the characteristics of sound radiating from a structure during a tap are changed by the presence of defects in the composite laminate. For structurally radiated sounds, the sound field is directly coupled to the structural motion. Therefore, impact response analysis should be performed. In this study, the radiated sound induced by tap was computed by solving the Rayleigh integral equation. Some damage models were also used to analyze the impact response and acoustic analysis of damaged composite laminates. The predicted impact force and sound pressure histories were compared with tap test data. The effects of in-plane load on the impact force and radiated sound were also investigated numerically.