基于应变模态小波变换的框架结构损伤识别研究

Damage identification of frame structure by means of wavelet analysis of strain mode

采用应变模态的小波变换方法研究了框架结构的损伤识别问题。以有限元分析求解含裂缝平面框架应变模态为基础,利用Guass2小波对框架的应变模态进行小波变换,再用db3小波对应变模态小波变换系数进行去噪处理,最后通过对去噪处理后的小波系数模极大值点来识别框架结构裂缝的位置,建立了基于应变模态小波变换识别平面框架损伤的方法。以一层平面框架为例,分别给出了框架梁含有裂缝、框架柱含有裂缝、框架梁和柱均含有裂缝的有限元模型,计算得到结构的应变模态,并通过应变模态小波分析来识别平面框架裂缝的位置。从识别结果发现,经小波去噪处理后应变模态小波系数的模极大值点能够有效识别框架结构的损伤,数值计算验证了方法的有效性。本文研究对工程结构损伤诊断有参考价值。

Based on wavelet transform of strain mode, the damage identification of plane frame was studied in this paper. Solving strain modal parameters of plane frames with cracks by means of the finite element theory, applying the gauss2 wavelet transform to analyse the stain mode of plane frame, and denoising the wavelet coefficients of the strain mode by db3 wavelet, then the location of crack of the plane frame could be identified by the maximum of wavelet coefficients after denoising. Therefore, this meth- od was proposed for damage identification of plane frames based on strain mode. Taking one-story plane frame for example, three finite element models, including a frame beam with a crack, each frame column with a crack, and each frame beam and column with a crack, were set up seperately, then the above- mentioned method was applied to identify the location of the crack. The results show that the method is effective, and it may be useful in damage identification and diagnosis in structures.