超声Lamb波与薄板中槽型缺陷相互作用的数值模拟  

Numerical Simulation on Interaction Between Ultrasonic Lamb Waves and Groove Defects in Thin Plate

作　　者：郑海超[1] 朱新杰[1] 邓明晰 Zheng Hai-chao;Zhu Xin-jie;Deng Ming-xi(Dept. of Foundation Science,LEU,Chongqing 401331,China)

机构地区：[1]后勤工程学院基础部,重庆401331

出　　处：《后勤工程学院学报》2017年第2期69-75,81,共8页Journal of Logistical Engineering University

基　　金：国家自然科学基金项目(11574399;11474361;11274388)

摘　　要：为探讨超声Lamb波在有缺陷薄板结构中的传播机制,在理论分析的基础上,运用有限元数值模拟方法,对薄板结构中Lamb波与槽型缺陷的相互作用规律进行研究。数值仿真结果显示:当对称激励源的驱动频率小于Lamb波A1模态的截止频率,板中只存在S0模态,由于槽型缺陷的存在破坏了薄板结构的几何对称性,将发生模态转换而产生A0模态;当改变槽型缺陷的宽度和深度,发现S0模态的反射比率η_S对槽型缺陷深度变化比较敏感,而A0模态的反射比率η_A对槽型缺陷宽度变化比较敏感,且Lamb波在缺陷处的模态转换比率与激发频率呈现单调增加关系。In order to investigate the propagation mechanism of ultrasonic Lamb waves with defects in thin plate,the interaction between Lamb waves and groove defects has been studied by using the finite element numerical simulation method based on theoretical analysis.The simulation analysis indicates there exists only the S0mode alone in plates when the driving frequency of the symmetric excitation source is less than the cut-off frequency of the A1mode.But the A0mode caused by mode conversion can be detected when the groove defects changes the geometric symmetry of thin plate.By changing the width and depth of groove defects respectively,the results show that S0mode reflection ratioηS is more sensitive to the depth of groove defects,while the A0mode reflection ratioηA is sensitive to width of groove defects.As the excitation frequency increases,the mode conversion ratio of Lamb waves at the defects will monotonically increase.

关 键 词：薄板结构 LAMB波 槽型缺陷 有限元模拟 

分 类 号：TG115.28[金属学及工艺—物理冶金]