基于等效结构应力法的塔吊焊接节点疲劳寿命评估

Fatigue life evaluation on welded joints of tower crane based on equivalent structural stress method

为了评估塔式起重机焊接节点焊缝处的疲劳性能,以QTZ25塔式起重机为例,利用有限元软件Ansys建立了包含焊缝细节的塔臂焊接节点模型.将模型导入FE-SAFE疲劳分析软件中,通过等效结构应力法完成了网格不敏感结构应力的转换,结合疲劳设计主S-N曲线,对塔臂焊接节点疲劳寿命进行了分析.结果表明:塔臂焊接节点焊缝处所能承受的最大循环次数为104.9459,满足工程需求;等效结构应力法具有网格不敏感性,能够较好地预测塔式起重机焊接节点焊缝处的疲劳寿命.

In order to evaluate the fatigue performance of welded joints at weld seam on tower crane,taking QTZ25 tower crane as an example,the finite element software Ansys was employed to build a welded joint model involving weld seam details of tower arm.The as-proposed model was imported into FE-SAFE fatigue analysis software for the transformation of grid-insensitive structural stress through an equivalent structural stress method.In combination with the main S-N curves for fatigue design,the fatigue life of welded joints on tower arm was analyzed.The results show that the maximum number of cycles that tower arm can withstand at the weld seam of welded joints is 104.9459,which meets engineering requirements.The equivalent structural stress method is grid-insensitive and can predict the fatigue life of welded joints at weld seam on tower crane better.