基于有限元与小波变换的弹性地基梁损伤识别方法研究

采用转角模态的小波分析方法研究了带刚度下降损伤段的弹性地基梁损伤识别问题.利用有限元分析求解带刚度下降段的模态参数,建立了基于转角模态小波变换识别弹性地基梁损伤的方法.以两端简支弹性地基梁为例,分别给出了地基梁无损伤、梁单独损伤、梁和弹簧同时损伤且损伤位置不同的有限元模型,计算得到了结构的转角模态,并通过转角模态小波分析来识别弹性地基梁内刚度下降段的位置.从识别结果发现,存在随机噪声的情况下,运用了转角模态小波变换方法,仍能识别出地基梁的刚度变化截面.数值算例证实了该方法的有效性和稳健性,研究结果对实际工程中的结构损伤诊断提供参考.

Research on Damage Identification Method of Elastic Foundation Beams Based on the Finite Element Methods and Wavelet Transform

Based on wavelet transform of strain mode,the damage identification decline of stiffness in elastic foundation beams was studied in this paper.Solving strain modal parameters of elastic foundation beams with stiffness decline by means of the finite element theory,applying the Mexh wavelet transform to analyse the stain mode of elastic foundation beams,and then the location of stiffness decline of the elastic foundation beams could be identified by the maximum of wavelet that coefficients with stochastic noises.Therefore,this method was proposed for damage identification decline of stiffness in elastic foundation beams based on strain mode.Taking a simple-supported beam on elastic foundation for example,three finite element models,including elastic foundation beams without damage,the beams with decline of stiffness,and the beams and foundation with decline of stiffness,were set up seperately,and then the above-mentioned method was applied to identify the location of stiffness decline of elastic foundation beams.The results show that the method is effective and stable,and it may provide useful evidence in damage identification and diagnosis in practical structures.