Delamination Damage Detection in a Composite Beam Using Discrete Wavelet Transform

An expectant attempt to detect delamination damage in a multi-layered composite beam using discrete wavelet transform is proposed. The finite element model of delamination-damaged composite cantilever beam is modeled using ANSYS-APDL software. The first mode of the simulated beam is obtained from the modal analysis. The deflection values of each node in the first mode shape are plotted to get the response of the top-most edge of the delaminated beam. Delamination in the composite beam causes a slope discontinuity in the beam elastic line. The top-most or bottom-most edge of the beam will also get affected due to such slope discontinuity. Detection of slope discontinuity will reveal the presence of delamination in the composite beam. However, it is quite difficult to identify the delamination in the presence of measurement noise. In the current work, a white Gaussian noise is added to the simulated beam responses to mimic the real experimentation. The noisy signal is used as an input signal for wavelet analysis. A dominant spike is observed at the damage position. The effectiveness of the present method is also analyzed with different values of signal-to-noise ratio (SNR).