Analysis of quantitative relationship between laser-generated guided waves and the adhesive interface by the numerical method

This research develops a guided wave technique to quantitatively characterize the adhesive interface properties of a nuclear radiation protection structure. The numerical model is established to investigate the propagation of laser-generated guided waves in a nuclear radiation protection structure that is composed of a 1045 steel sheet connected with a lead alloy (Pb-Sb-Sn) sheet by using an epoxy resin adhesive. The finite element method has been adopted to calculate the characteristics of laser-generated guided waves interaction with the adhesive interface. The propagation of structural guided waves in a single lead sheet and a multi-layered adhesive structure is analyzed and compared to explain the role of the adhesive layer. The investigation quantifies the influence of the relevant adhesive interface properties (bond thickness, Poisson’s ratio and Young’s modulus) on time- and frequency-domain characteristics of structural guided waves in the adhesive structure. The features of laser-generated guided waves interaction with interfacial defects are investigated to identify the discontinuity of the adhesive layer. The numerical results indicate that the characteristics of laser-generated guided waves would vary with different adhesive interface properties. Therefore, the research results would provide guidance for evaluating adhesive interface properties.