基于加速模态差值法的桁架结构早期损伤识别研究

Study on accelerating mode difference method about identification of forepart damage of boom

针对起重机械的桁架结构,分析了损伤的严重后果,提出了用加速模态差值法识别早期损伤。首先建立有限元模型,随机选取一根杆件,通过降低其刚度来模拟早期损伤;然后对未损桁架和损伤桁架分别进行模态分析,并提取两者的模态振型数据,通过计算机处理得到损伤前后的加速模态振型,然后进行对比分析,找出加速模态振型变化最大的节点,即为损伤节点,进而找到损伤杆件。实例分析表明,提出的方法合理可行。

Boom of lift machine is studied in this paper, severe result of damage is analysed and accelerating mode difference method provided to identify damage, finite element model is constituted, an bar of boom randomly selected, and early damage simulated by degrading its stiffness; Then mode of both intact and damaged boom analysed, mode shape data of them distilled, accelerating mode shape obtained by computer processing, they are contrasted, the node where accelerating mode shape changes the most severe located, then the node is damage node, and the damage bar found. Example demonstrates the method feasible.