基于改进残余力向量法的桁架结构损伤诊断

提出一种基于改进残余力向量法的桁架结构损伤诊断方法. 先由灵敏度分析， 求出结构刚度联系矩阵，再由刚度联系矩阵将损伤后的刚度摄动矩阵展开成对角矩阵，代入 残余力向量方程，得到由刚度联系矩阵表示的新的残余力向量方程，此方程可以直接求解， 即可诊断出桁架结构的损伤杆件及其损伤程度. 对于实测中难以获得完备振型的情况，采用 模态扩阶的方法来获得完备的测试振型. 最后以一桁架结构进行数值仿真分析，证实了该方 法的有效性.

DAMAGE DETECTION FOR TRUSS STRUCTURES BASED ON IMPROVED RESIDUAL FORCE VECTOR METHOD

A damage detection method for truss structures based on an improved residual force vector method is proposed. The stiffness connectivity matrix of the truss structures is obtained by the sensitivity analysis, and the stiffness matrix perturbation of the damaged structure can be expanded to a diagonal matrix by the stiffness connectivity matrix, then with its substitution into the residual force vector equation, a new residual force vector equation expressed by the stiffness connectivity matrix is obtained, which can be solved directly, so the stiffness perturbation of truss bars is obtained, therefore, the damaged bars and the damage extents can be detected. Because the complete modal shapes are difficult to get by measurement, the complete modal shapes are obtained by modal expansion. At last, a numerical example of a truss structure is given, the effectiveness of the proposed method is verified.