Ding Xiangyan, Li Feilong, Zhao Youxuan, Xu Yongmei, Hu Ning, Cao Peng, Deng Mingxi
College of Aerospace Engineering, Chongqing University, Chongqing 400044, China.
Key Laboratory of Optoelectronic Technology and Systems of the Education Ministry of China, Chongqing University, Chongqing 400044, China.
Materials (Basel). 2018 Apr 23;11(4):644. doi: 10.3390/ma11040644.
This paper investigates the propagation of Rayleigh surface waves in structures with randomly distributed surface micro-cracks using numerical simulations. The results revealed a significant ultrasonic nonlinear effect caused by the surface micro-cracks, which is mainly represented by a second harmonic with even more distinct third/quadruple harmonics. Based on statistical analysis from the numerous results of random micro-crack models, it is clearly found that the acoustic nonlinear parameter increases linearly with micro-crack density, the proportion of surface cracks, the size of micro-crack zone, and the excitation frequency. This study theoretically reveals that nonlinear Rayleigh surface waves are feasible for use in quantitatively identifying the physical characteristics of surface micro-cracks in structures.
本文采用数值模拟方法研究了瑞利表面波在具有随机分布表面微裂纹的结构中的传播特性。结果表明，表面微裂纹会引起显著的超声非线性效应，主要表现为二次谐波，三次/四次谐波更为明显。基于对大量随机微裂纹模型结果的统计分析，明确发现声学非线性参数随微裂纹密度、表面裂纹比例、微裂纹区尺寸和激励频率呈线性增加。该研究从理论上揭示了非线性瑞利表面波可用于定量识别结构表面微裂纹的物理特性。
