Damage Monitoring of Nanocomposite Structure Based on Super-resolution Microscopic Imaging Technology
In order to solve the problem that the dispersion and mode conversion of stress wave signals are complex in the process of damage monitoring of nanocomposite structures, which makes it difficult to analyze and interpret them, a damage monitoring method of nanocomposite structures based on super-resolution micro-imaging technology is studied. A super-resolution microscopic imaging system is constructed based on the pump-probe mode. The point spread function of the infrared microscopic imaging system is modified by the annular Lamb-wave pumping light. The resolution of the system breaks through the limitation of diffraction limit and solves the complex problems of dispersion and mode conversion of stress wave signal. The energy change of Lamb-wave in nanocomposite structure is visually presented. Based on the imaging results of super-resolution microscopic imaging system, the dispersion relation of low-order antisymmetric Lamb wave with propagation angle in anisotropic nanocomposite laminates is established by using Mindlin plate theory. Wavelet transform is used to analyze Lamb wave signals excited and received by piezoelectric sensors in time-frequency domain, extract characteristic information, and measure the actual flight time and group velocity of Lamb wave propagating in structures. On this basis, considering the influence of anisotropy on Lamb and wave velocity, the genetic algorithm is used to determine the damage location. The experimental study verifies the applicability and effectiveness of the proposed method.