基于列车动力响应的铁路桥梁损伤诊断方法

以桥梁单元的刚度下降率作为损伤指数,通过列车—桥梁耦合振动理论计算列车动力响应对桥梁损伤指数的灵敏度,并构建立灵敏度矩阵和建灵敏度方程,利用约束优化方法求解灵敏度方程得到各单元的损伤指数,实现对桥梁损伤的诊断。应用该方法对1座简支梁桥进行损伤诊断的结果表明:该方法对轨道不平顺不敏感;利用列车车体和转向架的加速度、速度和位移响应均能对桥梁进行准确的损伤诊断,但这3种响应信号中的位移响应最难测量,而且相对于转向架而言,在车体上更容易布置传感器,因此建议优先选用车体加速度和速度响应作为桥梁损伤诊断的输入;该方法既能诊断桥梁单一位置的损伤,也能识别桥梁多个位置的损伤。

Damage Diagnosis Method for Railway Bridges Based on Train Dynamic Responses

The stiffness reduction ratio of the bridge element is used as a damage index.Based on train-bridge coupled vibration theory,the sensitivities of train dynamic responses to damage indices are computed,and the sensitivity matrix and sensitivity equation are constructed.The sensitivity equation is solved with the constrained optimization method to get the damage indices of bridge elements,so that the bridge damage can be diagnosed.The diagnosis results of a simply-supported bridge indicate that the proposed damage identification method is insensitive to track irregularity.Bridge damage can be correctly diagnosed from the acceleration,velocity and displacement responses of the car body and the bogies.But the sensors can be placed more easily on the car body than on the bogies and the displacement responses are much more difficult to measure compared with other two kinds of responses.So the acceleration and velocity responses of the car body are preferred to be used as the inputs of bridge damage diagnosis.By the proposed method,both the single damage and multiple damage of the bridge can be identified.