120吨龙门起重机结构分析及基于遗传算法的主梁结构优化

发布时间：2018-08-03 21:23

【摘要】：龙门起重机广泛应用于社会生产和生活中的各个领域。本文所研究的120t龙门起重机钢结构的重量占整机重量相当大的比重,在整个起重机设计中占有重要地位。其金属结构的设计的优劣及力学性能直接决定了起重机的工作能力和工作质量;因此,起重机钢结构的设计显得尤为重要,对起重机钢结构的设计的研究是很有现实意义的。本文首先研究了目前国内外龙门起重机的发展现状以及发展趋势,根据要求对龙门起重机的钢结构设计进行了较深入的理论研究。利用ANSYS软件进行仿真模拟,计算了它的强度、刚度、稳定性并且进行了模态分析。在此基础上,运用遗传算法对龙门起重机主梁钢结构建立优化数学模型进行优化,完成龙门起重机主梁截面尺寸的优化设计,对优化后结果进行分析处理,在ANSYS中重新建模和分析,把分析结果和优化前结果进行比较,并验证优化后结构的强度、刚度、稳定性及固有频率。在理论基础上与实际相结合,本文具体内容分为以下几个部分: ①分析、研究龙门起重机工作机构以及主要钢结构的截面特点,建立有限元模型,对龙门起重机在六个最危险工况进行了有限元的静力学分析,按照《起重机设计规范》中的要求,验证其强度、刚度和稳定性。接着进行模态分析得出前十阶振型图。最后计算了起重机的稳定力矩和倾覆力矩,验证龙门起重机的抗倾覆稳定性。 ②根据龙门起重机的结构特点,对起重机主梁结构进行适当简化,以单根主梁的重量为目标函数,以主梁的高度、宽度及个桁架杆的截面参数为设计变量,以各杆件的强度和刚度为约束条件,来建立主梁的优化数学模型,运用遗传算法进行了优化计算。得到各个设计变量的最优值,达到了结构优化的目的。 ③将遗传算法优化分析得出的结果按照相关的型钢参数进行圆整,重新建立有限元模型,再次在ANSYS中进行仿真分析,对龙门起重机的强度、刚度、稳定性进行验证并与优化前的分析结果进行比较,优化后的整体重量比优化前的重量降低了11.4%。本文结合优化设计方法和有限元分析,对现行起重机机设计方法做了一定的改进和探索,为起重机的设计和优化提供了一定的辅助和参考作用。本文的最后提出了几点在将来有待继续研究的问题。
[Abstract]:Gantry crane is widely used in various fields of social production and life. The weight of steel structure of 120t gantry crane studied in this paper accounts for a large proportion of the weight of the whole crane and plays an important role in the design of the whole crane. The design of metal structure and its mechanical properties directly determine the working ability and working quality of crane, therefore, the design of crane steel structure is particularly important, and the study of crane steel structure design is of great practical significance. Firstly, this paper studies the present situation and development trend of gantry crane at home and abroad, and makes a deep theoretical study on the steel structure design of gantry crane according to the requirement. The strength, stiffness, stability and modal analysis are calculated by using ANSYS software. On this basis, the optimization mathematical model of the steel structure of the main girder of the gantry crane is established by genetic algorithm, and the optimization design of the section size of the main girder of the gantry crane is completed, and the results after optimization are analyzed and processed. Remodel and analyze in ANSYS, compare the analysis results with the results before optimization, and verify the strength, stiffness, stability and natural frequency of the optimized structure. On the basis of theory and practice, the concrete contents of this paper are divided into the following parts: 1. The section characteristics of gantry crane working mechanism and main steel structure are studied, and the finite element model is established. The finite element static analysis of gantry crane under six most dangerous conditions is carried out. The strength, stiffness and stability of gantry crane are verified according to the requirements of "Crane Design Code". Then modal analysis is carried out to get the first ten order mode pattern. Finally, the stability and overturning moment of the crane are calculated to verify the anti-overturning stability of the gantry crane. 2 according to the structural characteristics of the gantry crane, the structure of the main girder of the crane is properly simplified. Taking the weight of a single main beam as the objective function, taking the height, width and cross-section parameters of the main beam as design variables, and taking the strength and stiffness of each member as the constraint conditions, the optimization mathematical model of the main beam is established. Genetic algorithm is used to optimize the calculation. The optimal value of each design variable is obtained, and the purpose of structural optimization is achieved. 3. The result of genetic algorithm optimization analysis is rounded according to the relevant parameters of section steel, and the finite element model is re-established. The strength, stiffness and stability of gantry crane are verified and compared with the results before optimization. The overall weight of the optimized crane is reduced by 11.4g than that before optimization. Based on the optimization design method and finite element analysis, this paper improves and explores the current crane design method, which provides a certain assistant and reference for the crane design and optimization. At the end of this paper, some problems that need to be studied in the future are put forward.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH213.5

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