龙门铣床横梁结构静动态多目标优化设计研究

发布时间：2018-01-21 18:06

本文关键词： 龙门铣床横梁板壳理论灵敏度响应面法结构优化　出处：《陕西理工学院》2015年硕士论文　论文类型：学位论文

【摘要】：龙门铣床的横梁结构特性直接影响着加工精度及工作稳定性,本文以某大型龙门铣床的横梁为研究对象,通过概念建模、灵敏度分析和基于响应面法的目标驱动尺寸优化等技术,对大型横梁的结构优化进行了研究。根据龙门铣床的横梁属于薄壁结构这一特点,采用板壳单元对横梁结构建模,在方案设计时建立了三种结构形式的横梁。在方案比较中,应用有限元方法对三种横梁结构的静动态性能进行了仿真,通过对静载荷作用下横梁的变形和应力分布,以及三种横梁结构固有频率的分析比较,证实O型梁的静动态特性要优于其他两种结构形式。在建立横梁结构优化模型时,分析了结构质量、等效应力、三个方向的位移以及固有频率对横梁结构参数的灵敏度系数。为了提高优化效率,减小计算量和时间,最终确定横梁结构质量、Y方向最大位移和一阶固有频率为主要目标,采用灵敏度比值的方法筛选出有效的设计变量。在横梁结构静动态多目标优化中,以减轻重量为目的,对有效设计变量进行了基于响应面法的目标驱动尺寸优化,求解出设计变量的最优值,并对优化后的横梁结构进行了验证和分析,实现了横梁结构的轻量化设计。本文的建模方法、研究过程和结论对于具薄壳特征的结构如车辆、船舶、飞机的优化设计具有一定的参考意义。
[Abstract]:The structural characteristics of the gantry milling machine have a direct impact on the machining accuracy and working stability. This paper takes the crossbeam of a large gantry milling machine as the research object and models the model by concept. Sensitivity analysis and target driven dimension optimization based on response surface method are used to study the structural optimization of large beam. According to the characteristics that the beam of gantry milling machine belongs to thin wall structure. In this paper, three kinds of beams are built up by using plate and shell element. In the scheme comparison, the static and dynamic behaviors of the three kinds of beams are simulated by finite element method. The deformation and stress distribution of beams under static load and the natural frequencies of three kinds of beams are analyzed and compared. It is proved that the static and dynamic characteristics of O beam are superior to those of the other two structural forms. When the optimization model of cross beam structure is established, the structure mass and equivalent stress are analyzed. In order to improve the optimization efficiency and reduce the amount of calculation and time, the quality of the beam structure is finally determined by the displacement in three directions and the sensitivity coefficient of the natural frequency to the structural parameters of the crossbeam. The maximum displacement of Y direction and the first order natural frequency are the main targets. The effective design variables are screened by the sensitivity ratio method. In the static and dynamic multi-objective optimization of the beam structure, the aim is to reduce the weight. The effective design variables are optimized based on the response surface method (RSM), and the optimum value of the design variables is solved, and the optimized beam structure is verified and analyzed. The modeling method, research process and conclusions of this paper are useful for the optimization design of thin shell structures such as vehicles, ships and aircraft.
【学位授予单位】：陕西理工学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG542

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