利用振动响应的多种结构损伤识别方法比较

Comparison of various structural damage identification methods using vibration response

利用梁结构的不同模态参数(位移模态、转角模态、曲率模态)开展了梁结构裂纹萌生阶段的小尺度损伤识别方法的研究。首先,通过振动响应计算两跨简支梁的位移模态、转角模态以及曲率模态。其次,结合连续小波变换多分辨率和奇异性分析特性,计算3种模态参数变换后的小波系数,以辨识结构模态参数的奇异性。再次,通过对数值仿真数据加入不同程度随机噪声的方法来对比分析各方法对于结构损伤的识别效果。最后,通过实验测试数据分析各模态参数的损伤识别方法对于实际结构损伤识别的效果。结果表明,基于3种不同模态参数的损伤识别方法均能对小尺度的结构损伤进行定位,但各方法的抗噪性能不同,转角模态的抗噪性能最好,而位移模态次之,曲率模态较差。实验结果显示利用转角模态参数的损伤识别效果较好,而根据位移模态与曲率模态参数的识别效果相近,但曲率模态参数方法在较小损伤处的识别结果更容易被干扰。这为在工程实际中根据环境及振动响应特点进行损伤识别参数的选取提供了一定参考。

This paper mainly studies the different modal parameters of the beam structure(displacement mode,rotation mode,curvature mode)for the identification of small damage in the crack initiation stage.Firstly,the displacement mode,the rotation mode and the curvature mode of a two-span simply supported beam are calculated by the vibration response.Secondly,combined with the multi-resolution and singularity analysis characteristics of continuous wavelet transform,the wavelet coefficients transformed by three modal parameters are calculated to identify the singularity of structural modal parameters.Thirdly,the method of adding different degrees of random noise to the numerical simulation data is used to compare and analyze the recognition effect of each method on structural damage.The results show that the damage identification methods based on three different modal parameters can locate small-scale structural damage,but the anti-noise performance of each method is different.The anti-noise performance of the rotation mode is the best,followed by the displacement mode,and the curvature mode is poor.Finally,the experimental data is used to analyze the effect of the damage identification method based on each modal parameter on the actual structural damage identification.The experimental results show that the damage recognition effect of the rotation mode parameters is better,while the displacement mode and the curvature mode parameters have similar recognition effect,but the curvature mode is more likely to be interfered at the smaller damage.This provides a reference for the selection of damage identification parameters according to the environment and response characteristics in engineering.