板状结构非线性超声导波理论与成像方法研究进展

Advances in Theory and Imaging Method Studies of Nonlinear Ultrasonic Guided Wave for Plate-Like Structures

非线性超声导波对检测材料早期损伤具有独特的优势,可以大幅度增加结构状态管理域。但激励具有累积效应的非线性导波十分困难。一方面,非线性理论较为复杂。另一方面,非线性效应较弱,在试验中易受到噪声干扰。立足于板状非线性超声导波的发展,阐述了非线性导波波动理论,分析了产生累积二次谐波的必要条件,包括相位匹配和非零能量流耦合。简述了阵列导波成像方法的代表性研究进展,重点介绍了非线性超声导波与层析成像技术的结合。通过展示含有不同程度早期损伤的金属板材重构实例,证明了非线性导波对于微腐蚀、微裂纹和疲劳等早期损伤准确定位和损伤程度定量表征的能力。总结了非线性超声导波及层析成像技术的优势与面临的挑战,并预测了发展前景。

Nonlinear ultrasonic guided wave has the unique advantage of detecting early damage on materials which can significantly increase the management domain of structural state.However,it is hard to generate cumulative nonlinear guided waves.On the one hand,it is complexity of nonlinear theory.On the other hand,the weakness of nonlinearity makes it prone to be disturbed by noise in the experiment.Takes base of the developing of nonlinear ultrasonic guided wave for plate-like,the theory of nonlinear guided wave fluctuations is described and the necessary conditions on generating cumulative secondary guided waves are introduced,which include synchronism and nonzero power flux coupling.The progress of representative research of array guided wave imaging methods is introduced,especially the combination of nonlinear ultrasonic guided wave and tomography.The accuracy of nonlinear guided waves for locating early damage such as micro-corrosion,micro-crack and fatigue and expressing quantitative characterization of fatigue level is proved by showing examples of reconstructing plate metals with different levels of early damage.The advantages and challenges of nonlinear ultrasonic guided wave and tomography technology are summarized,and the development prospects are predicted.