基于当前多影响线信息的超静定梁损伤识别方法

Damage detection method for statically indeterminate bridge based on multi-influence line information in current state

针对超静定、变刚度梁损伤识别问题,提出基于当前状态多影响线信息的损伤识别方法,研究超静定梁式结构的影响线特征、局部损伤对梁应变影响线和挠度影响线的影响。基于实际应变影响线识别梁边界条件,以此构建损伤指标曲线,并根据其局部峰值点定位梁局部损伤。在此基础上建立包含损伤信息的基函数,对实际挠度影响线曲线进行最小二乘拟合计算,识别提取桥梁局部刚度折减信息即损伤定量化。开展移动车辆过梁数值仿真,结合数值计算响应进行损伤定位及定量研究。研究结果表明:所提出的损伤定位和定量方法不需要结构未损状态下的信息作为参考;当局部刚度折减量α介于0.1~0.5之间时,损伤检测结果均具有较高精度,从而验证了本文基于多影响线信息进行梁式结构损伤识别方法的正确性与可行性。

A multi-influence line based damage identification method was proposed for the statically indeterminate bridge structure with variable stiffness.Characteristics of influence lines of statically indeterminate beam structure was studied,and the influence mechanism of local damage on strain influence line and deflection influence line were compared.The bridge boundary condition was identified from the actual strain influence line,which was used to establish the damage index,and the damage location was determined according to the local peak value of the damage index curves.The basis function containing damage information was established,the least square method was used to fit the actual deflection influence line to identify the local stiffness reduction information,and the damage quantification was achieved.Numerical simulation of moving vehicles crossing a beam was carried out combined with numerical calculation response for damage location and quantification research.The results show that the damage location and quantification method in this paper does not require the information of undamaged structure as a reference.When the local bending stiffness reductionαis between 0.1 and 0.5,the damage detection results are highly accurate.Therefore,the correctness and feasibility of the beam structure damage identification method based on the multi-influence line information is verified.