为研究适用于下弦与撑杆改进构型张弦梁结构各杆件类型的损伤识别方法，降低在非损伤杆件处的误判，本文提出一种基于结构模态的子构件曲率变化损伤识别指标，通过对结构形式简单的简支梁结构进行分析，说明该指标的有效性。采用有限元软件ANSYS建立下弦与撑杆改进构型张弦梁结构分析模型，采用减小杆件单元弹性模量的方式模拟杆件损伤，考虑到结构对称且复杂，分别在跨中、1/4跨、近支座端杆件设置单损伤、多损伤、小损伤程度的损伤工况，采用子构件改进的曲率绝对差指标和本文提出的基于结构模态的子构件曲率变化指标进行损伤识别对比分析。结果表明：基于结构模态的子构件曲率变化指标可实现结构单损伤、多损伤精准定位；且该指标对于损伤程度较小的工况也非常敏感，可作为下弦与撑杆改进构型张弦梁结构损伤识别的有效方法。

In order to clarify the damage identification method applicable to each member type of beam string structures with improved configuration of lower chord and strut, and to reduce the misjudgment at non-damaged members, in this paper, a damage identification index of sub-component curvature variation based on structural mode is proposed, the validity of the index is illustrated by analyzing a simply supported beam structure with a simple structural form. The finite element software ANSYS was used to establish the analysis model of beam string structures with improved configuration of lower chord and strut, the damage of the member is simulated by reducing the elastic modulus of the member element. Considering the symmetry and complexity of the structure, damage conditions of single damage, multiple damage, and small damage level were set up in the mid-span, quarter-span, and near-bearing end bars, respectively, the improved curvature absolute difference index of sub-component and the sub-component curvature variation based on structural mode proposed in this paper are used for the comparative analysis of damage identification. The results show that the index of sub-component curvature variation based on structural mode can achieve the precise localization of single-damaged and multiple-damaged structures, and this index is also very sensitive to working conditions with a small degree of damage, which can be used as an effective method for the damage identification of the beam string structures with improved configuration of lower chord and strut.

国家自然科学基金资助项目(52378126)