【作者】 赵超凡；

【导师】 黄建龙；

【作者基本信息】 兰州理工大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 本文阐述了国内外起重机行业的发展状况、发展动态及起重机械在现代制造业中的重要作用。通过对龙门起重机现状的研究,针对国内龙门起重机箱形主梁存在的偏重,耗材多,成本高等缺点,对主梁进行了力学分析和优化设计。作者以甘肃省定西起重机厂生产的20t龙门起重机为对象进行了研究,在掌握大量实际生产应用的基础之上,用APDL语言以及参数化技术建立了龙门起重机结构的有限元参数化模型。这种建模方法在有限元分析过程中方便、快捷,特别是对模型的修改以及再次计算,不容易出错。本文研究了20t龙门起重机结构的静态和动态力学特性。通过静力学分析,确定了载荷位于梁中、梁端两种位置的危险点,并对主梁的强度和刚度进行了校核;结合有限元参数化模型,对主梁进行了模态分析,提取了前10阶固有频率、主振型及振型图,对其结果进行了分析。在模态分析的基础上,通过谐响应分析,得出龙门起重机在受外界激励作用下各阶危险频率的变形情况,为设计提供了依据。本文还对20t龙门起重机突然起吊的动载情况进行了瞬态分析。以主梁跨中满载时的轮轨接触点为基点,进行衰减振动分析,获得了龙门起重机突然起吊的瞬态动力响应,包括主梁垂直位移、垂直速度、垂直加速度与时间的响应曲线,得出衰减时间值,符合设汁规范的衰减时域。用有限元软件ANSYS为工具,对主梁做了受力分析和优化设计,优化后的主梁截面尺寸更加合理。经过优化的设计,减少主梁材料为12.4%,从而可以使主梁重量得以减轻,降低了制造成本。更多还原

【Abstract】 This thesis elaborated the situation, dynamic state and the direction of the development of the logistics equipment domestic and abroad currently, and the important function of logistics equipment in modern manufacturing industry. The paper also studies the present condition of gantry home and abroad, and researches mechanical analysis and optimization design of the main box girder. According to the shortcomings that the main girder of the portal gantry with box girder is over-weighted, needs more material and the cost is too higher.The author goes into a deeply research on the 20t gantry crane that produced by DingXi crane factory. After studying masses of the data in the production application and comparing fully, builds a portal structure’s parameterized FEM model using ANSYS internal command—APDL and parameterized method, which can modify and recalculate the model in FEM analyzing conveniently and quickly .This paper studies the structure of 20t gantry cranes static and dynamic mechanical properties. According to the static analysis, determines the danger points when the load at beam and the beam end position, and then checks the strength and stiffness of the girder; at the same time, Combing of the finite element parametric model, researches the modal analysis of the girder, gain the first 10 former natural frequency and mode shapes, and finally analyze the results. According to the modal analysis, the harmonic response analysis, ensures the deformation of the frequency bands dangerous situation, which provides the basis for the design.This article also studies the transient analysis of the 20t gantry crane when it lifting suddenly. Regard the contacting point which produced on the middle girder at the full load as basic point, analyses the vibration attenuation, gains the transient dynamic response which includes beam vertical displacement, vertical speed, vertical acceleration and time response curves, decay time. From the results, we can know that it meets the design specifications.The thesis researches mechanical analysis and optimization design of the main box girder based on the senior applied technique of ANSYS. From the results, we can see that the structure of the main box girder is more rational. After optimization. 12.4% material will be reduced, so if using the optimized result, can make to reduce the weight of the main girder, reducing the manufacturing costs.更多还原