Structural health monitoring based on laser excitation vibration test and wavelet transform

In this paper, a vibration testing and health monitoring system is proposed to detect damage in aluminum plate structures. This system is based on an impulse response excited by laser. A high power Nd:YAG pulse laser is used to produce an ideal impulse excitation via laser-ablation on an aluminum plate surface. The propagation, reflection and superposition of elastic wave will be happened in structures. Laser Doppler vibrometer is used for measuring data. And by means of spectrum analyzer and computer, wavelet transform is applied to analyze the waveform characteristics to detect and identify the location of the damage. The applicability of the present approach is validated by simulation and experimental results, demonstrating the ability of the method to detect and identify the location of damage induced on the aluminum plate structures.