基于Lamb波传播模型的缓变厚度板缺陷成像方法OA

The propagation behavior of Lamb waves in variable thickness plates is complex and exhibits significant dispersion effects,which leads to the difficulty of defect localization and imaging.A defect imaging method for slowly varying-thickness plates based on a Lamb wave propagation model is proposed in this paper.A Lamb wave propagation model for variable thickness plates is established,enabling the prediction of response signals through segmented constant thickness approximation and dispersion curve interpolation.A backward propagation phase compensation algorithm is introduced to eliminate signal distortion induced by dispersion effects.Combined with a delay-and-sum imaging algorithm,this approach achieves high-resolution defect imaging in the slowly varying-thickness plates.Numerical simulations and experimental studies are conducted to validate the proposed method.Numerical results demonstrate a positioning error of approximately 5.8 mm for an 8 mm diameter circular hole defect in a 500 mm×500 mm aluminum plate with thickness varying linearly from 2 mm to 4 mm.Experimental results confirm clear defect visualization with a positioning error of about 10 mm,verifying the method's applicability in defect detection for slowly varying-thickness plates.