悬索桥振动特性对结构参数的灵敏度

振动特性对结构参数的灵敏度对结构设计和诊断十分重要。用一阶随机摄动法建立悬索桥随机特征值问题的基本方程，求其动力特性对结构参数的灵敏度矩阵，并得到随机特征值的统计特征。结构随机参数按局部平均随机场理论离散。取主缆，桥塔和加劲梁的弹性模量和质量密度为随机场。在此基础上计算了青马桥自振频率的统计特征和对随机参数的灵敏度矩阵，并由此讨论随机参数对青马桥自振频率的影响。发现结构参数对悬索桥自振频率影响不显著，但自振频率对不同部位的参数的灵敏度系数有量级上的差别。

Sensitivities of natural modes of suspension bridges to structural parameters

On the basis of perturbation stochastic finite element method, the fundamental equations of eigenproblems of suspension bridges with random structural parameters were derived. The random parameters were discretized with the local averaging theory of random fields. The statistics of the natural frequencies of Tsing Ma bridge were calculated under the assumptions that the elasticity moduli and the mass densities of the main cables, stiffening deck and the towers were considered as random variables. The sensitivities of the natural modes were analyzed to these random variables. The numerical results show that the sensitivities to the basic variables at different locations are significantly different.