基于双谱和奇异值分解的结构损伤试验

Experimental study of structural damage based on bispectral analysis and singular value decomposition

介绍双谱和奇异值分解(SVD)的理论,通过计算结构振动加速度信号的双谱,根据不同荷载下双谱幅值的等值线变化规律来判断结构的损伤程度和评价结构非线性振动特征.利用奇异值分解方法计算双谱的主奇异值,根据主奇异值在不同荷载下的变化情况,来评价结构的损伤和非线性变化.2根钢筋混凝土梁在逐级加载下损伤破坏的试验数据分析结果表明,双谱及其奇异值对结构损伤的变化比较敏感,双谱及其奇异值的变化规律与试验过程中试件的裂缝发展和损伤情况相一致,可以应用于结构损伤的监测.

The theory of bispectral analysis and the method of singular value decomposition （SVD） were introduced. By the calculation of bispectra of structural vibration acceleration signals, the damage level and nonlinear vibration characteristics of structure were evaluated according to the variation of contour of amplitude of the bispectra under different loadings. The singular values of amplitude of the bispectra were calculated by SVD method and used to evaluate the damage degree and nonlinear variation of structure. The data analysis results of the experiment of two reinforced concrete beams which were damaged under s tepwise loading showed that the bispectra and singular values were high sensitive to the variation of structural damage. The variation of bispectra and singular values accorded with the cracks propagation of experiment records, which indicated that the bispectra and singular values can be applied to the monitoring of structural damage.