移动载荷作用的复杂箱型梁端部构形优化

Top Configuration Optimization of Complex Box Girder Under Moving Load

装配式建筑构件综合安装和冶金生产线常用的起重机箱型主梁端部变截面焊缝处存在明显应力集中,在变载荷作用下,会产生疲劳裂纹的构形不合理问题。以起重机箱型主梁为研究对象,建立了合理的有限元主梁参数化模型,并对其进行静力学分析。并通过有限元软件模拟箱型梁在移动载荷作用下的瞬态响应,得到箱型梁跨中的位移响应和端部应力响应。最后根据分析结果,采用热点应力法构建端部最大应力表达式,在保证箱型梁质量增加较小以及其他约束条件下,以端部应力最小为优化目标,建立优化模型,通过优化使箱型梁端部应力满足强度条件。将优化方案与初始方案对比,验证了优化方案的可行性。

There is obvious stress concentration at the welding seam of the variable section of the top of crane box girder commonly used in the comprehensive installation of prefabricated building components and metallurgical production lines.A reasonable parametric finite element model of crane box girder is established and its statics is analyzed.The transient response of the box girder under moving load is simulated by finite element software,and the displacement response and the stress response at the top of the box girder are obtained.Finally,according to the analysis results,the hot spot stress method is used to construct the expression of maximum stress at the top.Under the conditions of ensuring a small increase in the mass of box girder and other constraints,the optimization model is established with the minimum stress at the top as the optimization goal,and the stress at the top of box girder satisfies the strength condition through optimization.The optimized scheme is compared with the initial scheme,and the feasibility of the optimized scheme is verified.