考虑作业工况的架桥机主梁损伤识别研究

Damage Identification for Main Girder of Bridge Erecting Machine Considering Working Conditions

为防止架桥机主梁损伤诱发安全事故,进行作业工况下架桥机主梁损伤识别研究。以SXJ900/32型架桥机为研究对象,基于其架梁作业过程中主梁支承随时变化的现状,根据变形协调条件推导SXJ900/32型架桥机简化模型的力法方程;利用虚功原理求解结构挠度影响线的函数解析式,探求主梁支点存在高差情况下,基于挠度影响线曲率曲线的主梁损伤识别技术,并通过架桥机有限元模型仿真模拟进行验证分析。结果表明:利用架桥机主梁上测点的挠度影响线曲率曲线,可识别架桥机主梁的单点和多点损伤,但损伤处与测点的相对位置关系对损伤识别效果具有一定影响,结合2个测点的挠度影响线曲率曲线可取得最优识别效果;此外,利用挠度影响线曲率曲线不仅可识别损伤位置,还可较准确地量化判断损伤程度。

In order to prevent safety accidents caused by the main girder damage of bridge erecting machine,the damage identification for the main girder of bridge erecting machine under combined working conditions was studied.Taking SXJ900/32 bridge erecting machine as the research object,based on the current situation of the main girder support changing at any time during the operation of girder erection,the force-method equation of the simplified model of SXJ900/32 bridge erecting machine was derived according to the condition of deformation compatibility.The function analytic formula for the influence line of structural deflection was solved by the principle of virtual work.The damage identification technology of main girder based on the curvature curve of deflection influence line was explored in the case of the height difference between the fulcrums of the main girder,and the finite element model of bridge erecting machine was simulated to verify the analysis.Results show that the single point and multi-point damages on the main girder of bridge erecting machine can be identified by using the curvature curve of deflection influence line of the measuring point on the main girder.However,the effects of damage identification are affected to some extent by the relative location relationship between the damage location and the measuring point.The optimal recognition effect can be obtained by combining the curvature curves of deflection influence lines at two measuring points.In addition,the curvature curve of deflection influence line can not only identify the damage location,but also quantify the damage degree accurately.