桥梁结构损伤对其固有振动特性的影响

分析实际桥梁结构的各种损伤状况,采用矩阵摄动理论分析桥梁结构发生损伤时固有频率及振型向量的一阶、二阶摄动结果,并讨论了固有振动特性对结构单元损伤的灵敏性。在理论分析的基础上,编制桥梁结构固有振动特性及其在损伤下的摄动分析程序,并用以分析简支梁、连续梁及拱结构损伤引起的固有振动的摄动结果。分析结果表明:单一单元损伤引起固有频率的摄动结果很小;不同位置处单元损伤与固有频率摄动结果的关系曲线与对应振型曲线具有相似性,但在中间支承处或结构端部有扭转约束处单元损伤影响显著;而单元损伤对振型向量影响极小。

Effects of bridge damage on its free-vibration characteristics

All kinds of damage to bridge structures were analyzed.The first two orders perturbation of eigenvalues and eigenvetctors of damaged bridge structures was analyzed by applying the theory of matrix perturbation,and the sensitivity of eigenvalues and eigenvectors to element damage were discussed.Then the program of natural vibration of bridge structure as well as its perturbation was developed and used to analyze the perturbation of natural vibration of simple supported beam,continuous beam and arch structures.The results show that the perturbation of eigenvalues caused by damage of single element is very small,and the curves of the perturbation vs damage position are similar to the according modes and there are notable effects on the perturbation of eigenvalues when the damage is on middle support point or torsional constrained ends,and the effects on the eigenvectors are much light.