具有平行四边形截面的杆类结构波动特性分析

超声导波无损检测技术具有高效、快捷、灵敏等特点,应用前景广泛。复杂结构的无损检测方案,需要根据结构中超声导波传播特性分析结果进行优化选取。针对平行四边形截面杆,采用同时满足平行四边形域基本方程及斜边边界条件的斜坐标系,建立了完整的平行四边形杆的波动力学方程。采用分向半解析法,计算得到了平行四边形杆中超声导波的频散曲线,并分别研究了斜坐标系角度、对角线之比和邻边边长之比对纵向、扭转模态频散特性的影响规律。最后,通过导波激励、接收实验,验证了计算所得结论的正确性。

Wave motion characteristic analysis of parallelogram cross section bar structure

Ultrasonic guided wave non-destructive detection technique has broad application prospects for its rapid, sensitive and high efficient features. The non-destructive detection scheme for complex structure needs to be selected optimally based on the ultrasonic guided wave propagation characteristic analysis result of the structure. In this study, the complete wave motion dynamic equation for the parallelogram cross section bar is established by adopting the oblique coordinate system that meets the basic equation of the parallelogram region and the bevel edge boundary condition at the same time. Then, the directional semi-analytical method is applied to calculate the dispersion curves of the guided wave in the parallelogram cross section bar. The influences of the parameters (such as the angle of the oblique coordinate system, the ratio of the diagonal lengths and the ratio of the lengths of adjacent edges) on the dispersive properties in longitudinal and torsional modes are investigated. Finally, the guided wave excitation and receiving experiments were conducted, and the experiment results verify the correctness of the conclusions obtained with the proposed calculation method.