基于 nsoft的塔式起重机疲劳载荷谱编制及疲劳剩余寿命估算

摘要

以QTZ4508型塔式起重机为研究对象，在Ansys中建立其金属结构的有限元模型，通过静力学分析确定其危险位置，进而确定疲劳易发点。通过施工工地试验，检测起重臂不同位置不同工况下的应力－时间历程，经数据处理，绘出了A1、 A2工况下NO.9单循环下的载荷谱。另外，观察一周内塔式起重机的工况数，在nSoft软件中运用雨流计数法编制了塔式起重机一周内的载荷谱，并将载荷谱外推至1 a。根据编制的载荷谱和塔式起重机的P－S－N曲线，运用nSoft软件预测塔式起重机的疲劳寿命，推算出使用年限约16.6 a，为其安全评估提供了理论和技术支持。%With QTZ4508 tower crane as the study object, the finite element mode is developed for the metal structure in Ansys.The dangerous position is determined through static analysis to identify the spot where fatigue easily happens.Through the construction site test, the stress-time history of the cargo boom at different positions under different conditions is detected.By processing the data, the load spectrum of NO.9 under single cycle is plotted under cases of A1 and A2.In addition, through observation of the quantity of working conditions of the tower crane within one week, the one-week load spectrum for the tower crane is prepared using the rain-flow counting method.The load spectrum is extrapolated to 1a.Ac-cording to the load spectrum and the P-S-N curve, the fatigue life of the tower crane is predicted using nSoft, equal to about 16.6a, providing theoretic and technical support for safety evaluation.