瑞利波检测钢结构表面缺陷深度数值研究

Numerical Analysis of Depth Detection for Steel Surface Defect Using Rayleigh Wave

本文介绍了一种利用瑞利波在表面缺陷处的传播时间规律检测材料表面缺陷深度的方法,该法比较适合检测材质均匀的金属材料表面缺陷深度.在超高频率的激励作用下,介质表面产生的瑞利波波长远小于钢结构表面缺陷深度,瑞利波会沿着表面缺陷两个侧面传播到上表面.本文分析了各应力波的衍射和模式转换,及其各自传播路径;通过位移几何关系计算不同应力波的传播时间,确定计算钢结构表面缺陷深度的理论公式,通过有限元数值计算验证理论分析的正确性;研究了钢结构表面缺陷的定位方法;讨论激励频率,激励源和观测点位置,实际构件边界对检测结果的影响.

This paper introduces adepth detection methodfor surface defectsbased on Rayleigh wave＇s temporal regularity.The method is suitable for detecting surface defect depth of metal material.With the ultra high frequency excitation,Rayleigh wavelength is much less than the depth of steel surface defect.Rayleigh wave will propagate along two sides of the surface defect and then back to the steel top surface.Stress wave diffraction and mode conversion,and their respective propagation path are analyzed.Different stress wave propagation time is calculatedand the theoretical formula for computing the surface defect depth by displacement geometric relationship is determined.The validity of theoretical analysis is verified through FEM calculation.Steel surface defect location method is studied andThe effect of Four factors to the test result are discussed which included excitation frequency,excitation source,the observation point location,and the boundary for actual component