堆垛机柱脚焊接接头疲劳寿命分析及优化

Fatigue life analysis and optimization of welded joints in stacker column-footing

为了探究工作条件下堆垛机柱脚焊接接头的疲劳寿命问题,对堆垛机柱脚焊接接头进行了动载荷作用下的疲劳寿命分析,并对影响疲劳危险焊缝疲劳强度的相关尺寸进行了优化。首先,建立了含柱脚焊缝的堆垛机柱脚有限元模型,并使用典型受力模式下的静力学分析与焊线处结构应力分析,确定了柱脚危险焊缝位置;然后,建立了含柱脚危险焊缝的堆垛机有限元模型,采用动力学分析得到了动载荷作用下危险焊缝的疲劳载荷谱,并采用结构应力法求解得到了动载荷作用下的危险焊缝疲劳寿命;最后,针对危险焊缝疲劳强度较低的情况,使用响应面优化法对影响柱脚环形焊缝疲劳强度的尺寸进行了优化。研究结果表明:柱脚环形焊缝为柱脚疲劳危险焊缝;在极端工况下,堆垛机危险焊缝疲劳寿命为27.14 y,可以满足堆垛机设计使用年限;优化后的危险焊缝结构应力较优化前降低了15%,危险焊缝疲劳强度得到了较大提高。

In order to investigate the fatigue life of the welded joints of the stacker foot under working conditions,the fatigue life analysis of the welded joints of the stacker foot under dynamic loading and the optimization of the relevant dimensions affecting the fatigue strength of the fatigue hazard welds were carried out.Firstly,a finite element model of a stacker foot containing a foot weld was established,and the location of the dangerous weld at the foot was determined by static analysis and structural stress analysis at the weld line under typical stress patterns.Then,a finite element model of a stacker containing a dangerous weld at the foot was established,and the fatigue load spectrum of the dangerous weld under dynamic load was obtained by kinetic analysis,and the fatigue life of the dangerous weld under dynamic load was obtained based on the structural stress method.Finally,the dimensions affecting the fatigue strength of the annular weld at the foot were optimized using the response surface optimization method for the case of low fatigue strength of the dangerous weld.The research results show that the column foot ring weld is the column foot fatigue hazard weld;under extreme working conditions,the fatigue life of the stacker hazard weld is 27.14 years,which can meet the design service life of the stacker;the optimized hazard weld structural stress is reduced by 15%compared with that before optimization,and the fatigue strength of the hazard weld is greatly improved.