中文摘要：

为了更有效地使用超声技术检测功能梯度管道中纵向缺陷,基于3维弹性理论,采用一种正交多项式法研究无限长功能梯度材料管道中的周向导波.为验证方法的正确性与适用性,首先采用该方法计算均匀各向异性管道中的周向导波,并与已有数据相比较.其次,计算了不同梯度函数下管道周向导波的频散曲线,并与均匀管道进行了比较,说明了梯度材料管道中周向导波的特点以及梯度函数变化对频散曲线的影响.最后,求解了不同径厚比下功能梯度材料圆柱壳周向导波的频散曲线,分析了径厚比的变化对频散曲线的影响.

英文摘要：

In order to inspect longitudinal stress-corrosion cracks of large-diameter functionally graded pipes more efficiently, guided circumferential waves in infinitely long hollow cylinders were studied by an orthogonal polynomial approach. Properties of material were assumed to vary in the direction of the thickness according to a known radial variation law. The formulation was based on linear three-dimensional elasticity. Results from homogeneous cylinders were compared with that published earlier to check up the accuracy and range of applicability of the proposed approach. The guided circumferential wave dispersion curves of graded pipes under different gradient functions were calculated, and the effect of the gradient functions on dispersion curves was shown. Finally, the guided circumferential wave dispersion curves of graded pipes under different ratios of the inner radius to thickness were calculated to observe the effect when the ratio varied on the dispersion curves.