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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2016 Vol.17 No.3 P.215-229
Excitation of axisymmetric and non-axisymmetric guided waves in elastic hollow cylinders by magnetostrictive transducers
Abstract: Ultrasonic guided waves have been successfully applied in nondestructive evaluation (NDE) and structural health monitoring (SHM) of pressure vessels and pipelines due to their advantages, such as long detection range and high inspection efficiency. Compared with other ultrasonic guided wave actuators, magnetostrictive transducers are more cost-effective, involve simpler fabrication process, and have higher possible transduction efficiency. The normal mode expansion (NME) method is adopted to analyze the forced response and perturbation analysis of elastic hollow cylinders with respect to magnetostrictive loadings, including partial loading, axial array loading, and circular array loading. The phase velocity and frequency spectra of axisymmetric/non-axisymmetric guided waves excited by magnetostrictive transducers are analyzed. The theoretically predicted trends are verified by finite element numerical simulations and experiments.
Key words: Guided waves, Hollow cylinder, Normal mode expansion (NME), Magnetostriction
创新点:1. 利用简正模态展开方法,讨论弹性空心圆柱体在磁致伸缩载荷作用下的扰动分析和激励响应;2. 通过数值仿真和试验研究,验证空心圆柱体在磁致伸缩局部载荷、轴向阵列载荷和圆周阵列载荷作用下不同的激励响应,得到有效的结论。
方法:1. 通过理论推导,构建典型磁致伸缩换能器数学模型(公式(15)和(17));2. 通过理论推导,建立弹性空心圆柱体在磁致伸缩局部载荷、轴向阵列载荷和圆周阵列载荷作用下的波源分析模型(公式(25~26)、(30~31)和(34~35)),求解得到典型载荷形式下的激励响应(图6~8和11~13);3. 通过仿真模拟和试验研究,对空心圆柱体在不同磁致伸缩载荷作用下的激励响应进行验证(图14~21)。
结论:1. 磁致伸缩局部载荷能够激励产生同一族的导波模态,但是不具有良好的频率选择性和相速度选择性,轴对称载荷仅能激励轴对称模态;2. 磁致伸缩轴向阵列载荷具有良好的频率选择性和相速度选择性,中心频率和中心相速度取决于阵列单元间距,对导波模态控制非常有益;3. 磁致伸缩圆周阵列载荷能够激励周向阶次为阵列单元数整数倍的导波模态。
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DOI:
10.1631/jzus.A1500184
CLC number:
TB559; O347
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On-line Access:
2016-03-07
Received:
2015-06-21
Revision Accepted:
2015-10-13
Crosschecked:
2016-02-15