利用非线性导波检测早期损伤的潜在优势,在于其对微裂纹或以微结构变化的形式表现出来的材料性能退化的敏感性.而长距离传播能力使得振幅具有累积效应的非线性二阶谐纵向导波成为检测管道的理想方法.论文提出了在均匀各向同性的应力自由弹性固体管道中,产生轴对称二阶谐纵向导波的方案,该方案使用同频零阶纵向导波作为激励波.根据相速度匹配条件得到与此方案相对应的可能的谐导波生成点后,利用另一条件即非零功率流对生成点进行了数值验证,最终确定了在管道中产生二阶谐纵向导波的生成点. The potential advantage of using non-linear guided waves to detect early damage lies in its susceptibility to material degradation as evidenced by microcracks or in the form of microstructural changes, whereas the long-range propagation ability results in a nonlinear second order harmonic with cumulative effects Longitudinal guided wave is an ideal method to detect pipelines.The paper proposes a scheme of generating second-order axial longitudinal symmetric waveguides in a uniformly isotropic stress-free elastic solid pipeline by using the same-frequency zero-order longitudinal guided wave as the excitation According to the phase velocity matching conditions, the possible harmonic generation points corresponding to this scheme are obtained, then the generated points are verified by using the other condition, ie, the non-zero power flow, and finally the second harmonic generation in the pipeline Longitudinal wave guide generation point.