曲率模态参数法在张弦结构定量损伤识别中的研究和应用

Research and Application of the Curvature Modal Parameter Method in Quantitative Damage Identification of String Structures

针对目前张弦结构损伤识别动力检测只能定性判断的问题,提出能够定量识别的曲率模态参数法。以改进的曲率模态绝对差和曲率模态变化率为损伤识别指标,判断结构损伤位置,定量诊断损伤程度。以某体育馆大跨张弦梁结构为研究对象,建立ANSYS有限元模型,通过降低结构单元弹性模量模拟多种损伤工况,对损伤指标进行有效性验证。结果表明:仅获取低阶模态振型数据,采用改进的曲率模态绝对差指标能精准判断上弦构件损伤位置,曲率模态变化率指标能较精确识别上弦构件和下弦拉索损伤程度,方法简便,成本较低。

So far,damage identification of string structures based on dynamic detection can be only qualitatively estimated.Aiming at the subsistent problem,a method which could quantitatively identify curvature model parameters was proposed.The improved absolute difference indexes and variation ratio indexes of curvature modals were used to diagnose structural damage.Structural damage locations and damage degrees were determined by the above damage identification indexes.Taking a stadium with long-span beam-string structure as a research object,the ANSYS finite element model was constructed.In order to verify the availability of damage identification indexes,a variety of damage cases were simulated by reducing elastic moduli of structural elements.The results showed that structural damage locations of the upper chord member could be precisely judged by the improved absolute difference indexes of curvature modals,and structural damage degrees of the upper chord member and the lower chord cable could be accurately identified by the variation ratio indexes of curvature modals through lower-order modal data.The method was simple and low-cost.