环境温度影响下基于结构连续位移曲率组合的损伤识别方法

目的寻找对环境温度不敏感的损伤特征指标，消除环境因素在结构健康监测和损伤识别方法应用过程中的影响，准确识别损伤发生和定位损伤位置．方法对静力作用下的结构位移进行中心差分求取结构各节点的位移曲率，将任意相邻三个节点间静位移曲率进行线性组合构建新的损伤指标．利用北京一年的实测温度数据模拟环境温度变化，通过一个简支钢梁的仿真算例验证方法的有效性．结果算例中梁上各节点损伤指标不随温度的变化而变化，在损伤单元相邻两节点处出现正向跳跃，与损伤单元相邻的左右两单元的外侧节点处出现负向跳跃，而更远处的未损伤单元节点处的损伤指标则始终保持在0值附近波动，据此损伤单元得到准确定位．结论利用结构连续位移曲率组合的损伤识别方法可以有效消除环境因素的影响，准确识别损伤发生和定位损伤位置，无需结构健康状态基准数据，具有一定的噪声鲁棒性．

Damage Detection Method Based on the Combination of Successive Displacement Curvature under the Influence of Environmental Temperature

In order to eliminate the external environmental influence on civil structural health monitoring and damage identification and to realize the damage identification and localization accurately, this paper studied the damage detection features which are insensitive to environmental temperature variation. A new damage identification index,i, e. a liner combination of three successive displacement curvatures which were numerically obtained by a central difference approximation method, was proposed. Using simulation for a simply supported steel beam with environmental temperature change obtained from one year＇ s temperature record in Beijing, validity and effectiveness of the proposed method was illustrated. Simulation result shows that the identification index of the nodes on the beam is not changed with the temperature variation. Meanwhile, the index also presents a distinct positive jump for the nodes of damage element and a negative jump for the nodes beside the damage element. But for the nodes farther away from the damage one, the index stays stationary and fluctuates around zero, thus the damage element location could be identified. It can be concluded that the proposed method can eliminate the influence of environmental temperature. The damage detection and localization can be accurately identified without structural original data in healthy condition. It is also found that the methode has noise robustness.