基于附加质量的试验模态振型质量归一化

Way of Getting Mass-Normalized Experimental Mode Shapes Based on Mass Changes

针对桥梁结构试验模态振型的质量归一化,探讨了基于附加质量的试验模态振型质量归一化法,给出它的4种方法。以通扬运河大桥和张家港河大桥的有限元模型为对象,对4种方法计算质量归一化因子的精度,以及质量块的数量和质量、传感器数量、模态振型误差、质量块质量的误差对精度的影响进行了仿真研究。仿真结果说明了基于附加质量的试验模态振型质量归一化法的可行性和可靠性,在实际工程应用中可实现桥梁各阶试验模态振型较高精度的质量归一化。

Using operational modal analysis technology, the experimental modal parameters of bridge structure are easily and rapidly gained. But mass normalization of experimental modal shapes still is one of unsolved problems. For mass normalization of experimental modal shapes of bridge structure, this paper presents a way that is mass normalization of experimental modal shapes based on mass changes, and its four methods to calculate the scaling factors of experimental modal shapes. Based on the finite element models of Tongyang canal and Zhangjiagang river main bridge, the accuracies of scaling factors with four methods and the effects of mass change numbers, mass change weights, sensor numbers, shape errors and mass change errors to the accuracy of scaling factors are discussed. The results show that the way is feasible and reliable to mass normalization of experimental modal shapes, and can achieve the precise mass normalization of experimental modal shapes.