Damage Detection in Laminated Composite Plates Using Wavelet Analysis Analytical Method

Composite materials are increasingly employed in varying industries. Health monitoring in composite members is a further issue of interest to researchers. When damaged, the structure responds differently because of alterations in mechanical properties (i.e., mass, stiffness, and damping). The health of the structure and structure members can be monitored by examining how the responses have changed. This paper aimed to detect damage in an 8-layer composite plate, in which each pair of successive layers are connected at a 90-degree angle. First, the composite plate was modeled and undergone frequency analysis in ABAQUS software and the information concerning damaged and non-damaged modes was extracted. Subsequently, the damage was detected by defining a two-dimensional signal (the sum or difference of the shape of healthy and damaged modes) as the input of a two-dimensional discrete wavelet transform. The results showed turbulence and perturbation in the wavelet coefficients obtained from the diagonal details of the input signal’s wavelet analysis in damaged areas so that with a simple inspection, the damaged areas could be easily identified. According to the results, the proposed technique is an efficient method of damage detection in laminated composite plates.