基于空间-频率-波数法的梁中分层缺陷定量检测

Quantitative Detection of Lamination Defect in Beams Based on Space-frequency-wavenumber Method

为了描述梁中Lamb波的传播特性并对梁中的分层缺陷进行定量检测,以铝梁为研究对象,分别从有限元仿真和试验两方面进行研究。采用基于Matlab和ABAQUS相结合的方法,构建含分层缺陷的铝梁三维有限元仿真模型。通过提取覆盖缺陷的矩形区域接收点的时域信号,对铝梁中Lamb波与分层缺陷的作用规律进行分析。讨论对称边界和自由边界两种条件下,波场幅值分布的一致性与差异性,并得到了入射波幅值在梁宽度方向上的变化规律。同时,搭建EMAT/激光检测系统对有限元仿真结果进行验证,发现二者具有良好的一致性。针对接收波形中复杂的时域信息,采用空间-频率-波数法对铝梁中的分层缺陷进行定位和定量评估。研究结果表明,从仿真和试验分析,采用空间-频率-波数法对铝梁中分层缺陷的测量误差均在6%左右。

In order to depict the propagation characteristics of Lamb waves in beams,and quantitatively detect the lamination defect,an aluminium beam structure is used as a research object by using both finite element and experimental analysis,respectively.Based on the combination of Matlab and ABAQUS,a three-dimensional finite element model of aluminum beam with lamination defect is constructed.By extracting the time domain signal of the rectangular receiving area covering the defect,the behaviours of Lamb wave interacts with lamination defect are studied.Two circumstance,symmetric boundary and free boundary,are simulated to discuss the consistency and difference of the amplitude distribution in the wavefield.The phenomena of the incident wave amplitude varies with the beam width is obtained.Meanwhile,the EMAT/laser detection system is set up to verify the finite element simulation results,and found that the two have good consistency.For the complex time domain information in the received waveforms,the space-frequency-wavenumber method is used to locate and quantitatively evaluate the lamination defect in the aluminum beam.The results of the study indicate that the measurement error is about 6%in both simulation and experimental analysis by using space-frequency-wavenumber method.