桥式起重机主梁端部优化方法研究

Bridge Crane Girder end Optimization Method Research

在桥式起重机金属结构的定期检查中,经常在主梁端部过渡圆弧区域的焊缝位置发现裂纹,故在主梁的轻量化设计中需要考虑这一部位的疲劳特性。提出了一种基于热点应力评定主梁端部过渡圆弧区域疲劳特性的优化设计方法,通过有限元仿真计算获得了相应的热点应力集中系数表达式。以结构质量最小为设计目标,在静强度、静刚度、稳定性等常规约束基础上,加入了主梁端部圆弧区段疲劳强度的约束,建立了箱形主梁结构的优化模型。基于Matlab的比较实验证明,在轻量化优化设计中综合考虑端部疲劳特性,其结果具有更高的可靠性。

During the periodical inspection of the crane＇s metal structure,cracks were often found at the weld of the transition arc region at the end of the main girder.So,it is necessary to consider the fatigue performance about this area in the lightweight designing of the main girder.A new optimization method which employs the hot spot stress method to evaluate the fatigue properties about the transition arc region at the ends of the main girder was proposed.The related hot spot stress concentration factor formula was obtained by finite element simulation.Taking the mass of the structure as the design goals and the fatigue strength of the transition arc segment of the main girder as a new constraint,together with conventional constraints like the static strength,the stiffness and the stability,the optimization model for the box main girder was established.The computing experiments based on Matlab show that the result will get higher reliability in the lightweight optimization design with fatigue properties considered.