【摘要】 从理论上分析Lamb波群速度识别铝合金疲劳损伤的可行性。搭建主动Lamb波结构健康监测系统,采用基于Lamb波群速度的结构损伤检测方法,研究金属疲劳引起的损伤形变的识别过程;通过波包分解技术将接收信号中混叠的激励波包分解出来,从而准确地提取波包的到达时刻,实现Lamb波传播群速度的计算。在实际7050铝合金板材结构上进行了实验验证,并与短时傅里叶变换法进行对比。实验结果表明,采用波包分解技术能准确获取波包的传播时间,通过对比群速度识别金属疲劳的存在,其有效性高于短时傅里叶变换法。更多还原

【Abstract】 The feasibility of using Lamb wave group velocity to identify aluminum fatigue damage is analyzed theoretically in this paper.Active Lamb structure health monitoring system is established,and the method of structural damage detection based on Lamb wave group velocity is utilized in the identification process of damage deformation due to metal fatigue.In order to accurately obtain the arrival time of wave packet and Lamb wave group velocity,wave packet decomposition technique is employed to extract excitation wave packet aliasing from the received signal.Moreover,the proposed method is verified by the experiments on the real 7050aluminum alloy sheet structure,and compared with the short-time Fourier transform(STFT)method.Experimental results show that the proposed method can accurately obtain the wave packet propagation time and identify the existence of metal fatigue by comparing the group velocity.Also,the proposed method is more effective than the STFT method.更多还原