应用有限元方法将多跨连续梁结构简化为弱耦合的欧拉-伯努利梁模型,利用Newmark积分法直接积分求出系统在外激励作用下的动态响应.在结构损伤识别过程中以结构抗弯刚度的减少作为损伤识别参数,通过最小二乘法构造同伦方程.该方法的收敛不依赖于初始值选择,且可对具有重频的多跨结构进行准确识别.讨论模拟人工测量噪声对损伤识别结果影响.数值模拟算例表明该方法能快速有效检测出弱耦合梁的局部损伤,具有精度高、对测量噪声不敏感等特点.%Here,a multi-span continuous beam was modeled as a weakly coupled Euler-Bemoulli beam system by using the finite element method.The system dynamic response was obtained by using Newmark direct integration method under external excitation forces.In the process of structural damage identification,the reduction of elemental flexural rigidity was used as a damage parameter.A homotopy equation was constructed with the least square method iteratively.The convergence of the method did not depend on the choice of the initial values.And this method was able to identify damage of a multi-span structure with repeated natural frequencies accurately.The effect of artificial measurement noise on the identified damage results was also discussed.Numerical simulations showed that the proposed method can detect quickly and effectively damages in a weak coupled beam system,andit is insensitive to measurement noise.
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