异形高耸专用塔机动载响应分析及多目标优化

发布时间：2018-09-01 09:52

【摘要】：异形高耸专用塔机是由中国建筑科学研究院建筑机械化研究分院设计并投入试制的一种新型起重升降综合装备。其主要施工对象为火电厂冷却塔、高速公路索塔、烟囱等垂直高度大、外形不规则的建筑,用以解决普通塔机在此类建筑施工中存在的设备利用率低、工作半径局限等问题。由于新结构的塔身标准节省去了端面斜腹杆,且施工平桥的爬升会使整机的迎风面积变的很大,这就使得塔机在瞬态力的作用下容易引起较大的冲击振动,影响到工作稳定性。本文以复杂动载荷作用下的结构响应情况和稳定性为主要研究内容,对异形塔机进行了有限元分析和优化设计。在分析异形高耸塔机主要结构组成和功能特点的基础上,利用APDL语言对金属结构进行了参数化建模。基于此模型,对异形塔机进行了不利工况下的静力分析,同时完成了模态分析及谐响应分析。针对风载荷中的脉动成分,采用线性滤波法对不同高度处的风速时程进行模拟,并将结果导入ANSYS中进行瞬态动力学分析,探究其产生的振动效果以及对塔机强度和稳定性的影响。此外,通过等效惯性矩法把塔身格构式结构等效为实腹式结构,计算出塔身不同高度时的屈曲临界载荷,并与ANSYS非线性分析得到的结果进行比较,得出较为可靠的异形塔机极限载荷值。以异形塔机关键模态频率最大、动载系数最小、质量最轻为设计目标,构建i SIGHT与ANSYS多目标联合优化平台。通过ANSYS中的灵敏度分析,确定响应值较大的结构参数为设计变量。优化过程采用非支配排序遗传算法(NSGA-II),最终得到Pareto非劣解集。优化结果反应出了各优化目标之间的影响关系,为设计静动态性能皆优的起重机金属结构提供了参考。
[Abstract]:Special-shaped towering tower crane is a new type of lifting and lifting comprehensive equipment designed and trial-produced by the Research Institute of Building Mechanization of the Chinese Academy of Architectural Sciences. The main construction object is the cooling tower of thermal power plant, highway cable tower, chimney and other buildings with large vertical height and irregular shape, which is used to solve the problems of low utilization ratio of equipment and limitation of working radius of common tower crane in this kind of building construction. Because the standard of tower body of the new structure saves the end face inclined web bar, and the climbing of the construction flat bridge will make the upwind area of the whole machine become very large, this makes the tower crane easily cause larger shock vibration under the action of transient force and affect the working stability. In this paper, the structural response and stability under complex dynamic loads are taken as the main research contents, and the finite element analysis and optimization design of the special-shaped tower crane are carried out. Based on the analysis of the main structure and function characteristics of the special-shaped towering tower crane, the parameterized modeling of metal structure was carried out by using APDL language. Based on this model, the static analysis of special-shaped tower crane under unfavorable working conditions is carried out, and the modal analysis and harmonic response analysis are completed at the same time. According to the fluctuating components of wind load, the linear filtering method is used to simulate the wind speed time history at different heights, and the results are introduced into ANSYS for transient dynamic analysis. The vibration effect and the influence on the strength and stability of tower crane were investigated. In addition, the lattice structure of the tower is equivalent to the full-web structure by the method of equivalent moment of inertia, and the buckling critical load at different heights of the tower is calculated and compared with the results obtained by ANSYS nonlinear analysis. A more reliable limit load value of special-shaped tower crane is obtained. The optimization platform of I SIGHT and ANSYS is constructed with the maximum key mode frequency, the smallest dynamic load coefficient and the lightest mass as the design goal. Through the sensitivity analysis in ANSYS, the structural parameters with large response value are determined as design variables. In the optimization process, the non-dominated sorting genetic algorithm (NSGA-II) is used to obtain the Pareto noninferior solution set. The optimization results reflect the relationship between the optimization objectives and provide a reference for the design of crane metal structures with excellent static and dynamic performance.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH213.3

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