中文摘要：

奥氏体不锈钢呈现出明显声学各向异性,如何检测与评价这类材料成为声学检测领域的研究难点和热点问题。应用多高斯声束模型来研究超声换能器向各向异性圆管堆焊结构中辐射声场的特征。给出声场模型中材料各向异性系数的具体求解方法;并应用该声场模型计算超声束在有机玻璃楔块、各向异性堆焊层和低合金钢基体三层介质中的传播特征,重点分析堆焊层各向异性和圆管曲率变化两种因素对纵波声束偏转和聚焦形态的影响。进一步,将多高斯声束模型与分离变量法缺陷散射模型相结合,建立适用于各向异性圆管堆焊结构的超声测量模型,用于预测各向异性堆焊层下的横通孔缺陷回波信号。试验测量结果与模型预测结果的比较表明,两者的信号幅度和相位都符合较好。

英文摘要：

Ultrasonic inspection on the welded seam of austenitic stainless steels is a difficult and hot issue since the typical anisotropic behaviors will appear in this kind of welded joint.The propagation behaviors of ultrasonic beam in the tubing weldment with austenitic buttering are investigated with the help of multi-Gaussian beam models.The anisotropic coefficients used in the multi-Gaussian beam model are discussed and provided.The beam propagations in Lucite wedges,buttering layers and base steels are simulated,and the beam steering and focusing influences due to both of the curved surface and the anisotropic behavior are analyzed in detail.Furthermore,an ultrasonic measurement model for the tubing weldment with austenitic buttering is developed by combining the multi-Gaussian beam model and a scattering model with the separation variable method.This model can be used to predict the testing signals from the side-drilled holes below the anisotropic buttering layer.Also the accuracy of the provided model is verified by the comparisons of the model predictions with the experimental results,and the signal amplitude and phase of the both are in good agreement.