周向导波在空心圆柱体中传播的数值模拟研究

在石油、化工、食品和城市供水等行业,由于腐蚀等原因而引起泄漏事故,造成巨大的经济损失和资源浪费.因此,能够预先检测到管道缺陷避免事故发生显得十分重要.基于弹性动力学理论,利用Matlab编程实现周向导波在空心圆柱体中传播的数值模拟.利用特征函数展开法计算出周向导波的频散曲线及0.6MHz和1MHz各个模态的时域波形图并据此分析激励方式同周向导波传播的关系,频率为1MHz或0.6MHz时,1和2模态在空心圆柱壳中传播的周向导波中处于主导地位:各模态的径向或周向位移幅度会受到激励入射角的影响而变化并且周向导波的位移幅度随着激励入射角的增加而增加:得到特定频率下,周向导波各模态径向、周向位移的变化关系.本文结果为进一步利用实验方法研究周向导波在空心圆柱体中传播特性和缺陷检测奠定了基础.

Numerical Simulation of Guided Circumferential Wave Propagation in Hollow Cylinder

In oil,Petro-chemical,food and city water supply industries,pipe leakage resulted from defects such as corrosions,often occurs and leads to great economy loss and resource waste.Therefore,finding out those defects in pipe prior to leakage accidents is very important.Based on elastic dynamics mechanics,the numerical simulation of guided circumferential wave propagation in hollow cylinder by Matlab programming was achieved.The method of eigenfunction expansion was used to calculate the disperse curves of guided circumferential waves and the waveforms of guided modes at 0.6MHz and 1MHz.Utilizing them,the relationship between exciting manners and propagation of guided circumferential waves was an-alyzed.At 1MHz and 0.6MHz,modes 1 and 2 are dominant among all guided circumferential wave modes propagating in hollow cylinder Excitation angles will affect the displacement amplitudes of guided circumferential waves and the displacement amplitudes of guided circumferential waves increase with the increase of excitation angles is confirmed.Finally,the shifting relation of radial displacement and circumferential displacement of each guided circumferential wave mode at certain frequency was found.These theoretical results lay a foundation for experimental research of propagation characteristics of guided circumferential waves in hollow cylinder and their application to defect detection.