【摘要】 针对焊接空间结构节点易发生损伤和破坏的问题,为了识别焊接空间结构节点焊缝拉裂损伤,建立了节点焊缝拉裂损伤等效模型,考虑到焊接空间结构具有杆件和节点众多的特点,提出了损伤识别两步法。首先建立有焊缝拉裂损伤焊接球节点三维实体有限元模型,划分焊缝裂缝宽度,然后分析不同焊缝裂缝宽度与节点刚度系数之间的关系,最后将所获得的不同裂缝尺寸焊接球节点刚度系数等效为弹簧刚度,施加于结构杆件两端,成为杆端弹簧约束模型,即考虑节点焊缝拉裂损伤的等效有限元模型;建立等效模型后,采用两步法识别节点焊缝拉裂损伤位置,先对结构分区,用小波分析方法识别结构杆件有节点焊缝拉裂损伤发生的区域,然后基于等效模型提取应变模态作为损伤标示量,在损伤区域内具体定位有节点焊缝拉裂损伤发生的杆件。结果表明:焊缝拉裂损伤等效模型能够模拟实际结构节点焊缝拉裂损伤,所建立的节点焊缝损伤等效模型易于提取损伤标示量,采用两步法能够识别出焊接空间结构节点焊缝拉裂损伤位置。更多还原

【Abstract】 Aiming at the problem that the welded joints of space structures being prone to damage,in order to identify the weld crack damage of welded space structural joints,the equivalent model of weld damage was established,and a two-step damage identification method was proposed to consider the characteristics of welded space structures with many joints and bars.Firstly,the three-dimensional solid finite element model of spherical joints with weld crack damage was established,and the weld crack width was partitioned.Then the relationship between the weld crack width and the stiffness coefficient of joints was analyzed.Finally,the stiffness coefficient of welded spherical joints with different crack widths was equivalent to the stiffness of spring,which was applied to the end of the rod as a spring restraint.Therefore,the equivalent finite element model of crack damage of welded joints was established.After establishing the equivalent model,the two-step method was used to identify the location of weld damage joints.Firstly,the structure was divided into several zones,and the zone containing weld damage joints was identified by wavelet analysis method.Then,based on the equivalent model,the strain modes were extracted as damage indicators to locate the weld damaged joints in the damaged zone.The results show that the equivalent model of weld crack damage can simulate the actual structural joint with weld crack damage.The proposed equivalent model of joint weld damage established is easy to extract damage indicators.The two-step method can identify location of the damaged joint of welded spatial structures.更多还原