现代伸缩臂截面及尺寸优化研究

发布时间：2018-10-31 11:43

【摘要】：汽车起重机因具有结构紧凑、移动方便、灵活性强、工作条件与场地适应性强等特点,而被广泛应用在各工程领域。汽车起重机的承载部件伸缩臂在整机中是重点设计的部件。其主要承受双向压弯载荷,受力非常复杂,其截面形式与质量直接决定整机性能。在伸缩臂的结构强度、刚度和稳定性条件都得到满足的同时,研究其截面形式并减轻自重,对于整机性能的提高有着重要意义。随着设计水平的不断提高和新材料的使用,汽车起重机朝大吨位、大高度方向发展,使得伸缩臂重量也不断增加。为了减轻伸缩臂自重,充分发挥材料性能,许多截面形式被采用,其中包括新型椭圆截而形式的采用。这种截面形式由于圆弧下槽板与斜腹板的采用,使得伸缩臂结构抗屈曲能力大为增加,受力更加合理,整机重量更轻。而且该种截面形式伸缩臂结构腹板的屈曲临界载荷有显著提高,但是对于圆弧下槽板出现了新的局部稳定性问题。本文核心为研究新型椭圆截面伸缩臂局部稳定性计算方法,利用特征值有限元法对圆柱壳屈曲计算解析法进行修正,并运用在伸缩臂结构尺寸优化之中。本文以六边形、八边形和新型椭圆形截面伸缩臂为研究对象,对其进行受力分析,考虑伸缩臂结构的非线性弯曲,分别建立了变幅平面与回转平面的力学模型,并得到了力学约束条件。以伸缩臂自重为目标函数,以截面尺寸作为设计变量,并考虑套接长度对局部稳定性的影响,采用搜索性能好、自适应性与收敛速度快的遗传算法,利用Matlab软件实值编码方式编写优化程序,完成基于Matlab语言的伸缩臂性能尺寸优化可视化软件的编写。本文将QY70型汽车起重机的整机性能参数运用到三种截面形式伸缩臂的优化中,输出每次迭代中的最佳个体。经优化计算后的六边形、八边形和新型椭圆截面形式的伸缩臂自重比优化前分别下降了7.7%、9.2%、15.1%,验证了程序的可行性并达到优化的效果。本文对实际工程中伸缩臂设计有一定的指导意义。
[Abstract]:Truck crane is widely used in various engineering fields because of its compact structure, convenient movement, strong flexibility, strong adaptability to working conditions and site. The telescopic arm of truck crane is an important part in the whole machine. It is mainly subjected to two-way compression and bending load, and the force is very complicated. Its cross-section form and quality directly determine the performance of the whole machine. While the structural strength, stiffness and stability conditions of the telescopic arm are satisfied, it is of great significance to improve the performance of the whole machine by studying its cross-section form and reducing its weight. With the improvement of design level and the use of new materials, truck cranes are developing in the direction of large tonnage and height, which makes the weight of telescopic boom increase. In order to reduce the self-weight of the telescopic arm and give full play to the material properties, many cross-section forms have been adopted, including the new elliptical truncated form. Due to the adoption of circular subarc grooves and oblique web the bending resistance of the telescopic arm structure is greatly increased the force is more reasonable and the weight of the whole machine is lighter. Moreover, the critical buckling load of the web plate of this kind of cross section telescopic arm structure is improved significantly, but there is a new local stability problem for the circular subarc grooved plate. The core of this paper is to study a new method for calculating the local stability of a telescopic arm with elliptic section. The eigenvalue finite element method is used to modify the analytical method for calculating the buckling of cylindrical shells, and it is used in the optimization of the structure size of the telescopic arm. In this paper, hexagonal, octagonal and new elliptical section telescopic arms are studied. The mechanical models of the variable amplitude plane and the rotary plane are established by considering the nonlinear bending of the telescopic arm structure. The mechanical constraints are obtained. Taking the weight of the telescopic arm as the objective function, the section size as the design variable, and considering the influence of the socket length on the local stability, the genetic algorithm with good searching performance, high adaptability and fast convergence is adopted. The optimization program is compiled by using the real value coding method of the Matlab software, and the visual software for the optimization of the performance and dimension of the telescopic arm based on the Matlab language is completed. In this paper, the whole performance parameters of QY70 truck crane are applied to the optimization of three kinds of cross section telescopic boom, and the best individual in each iteration is outputted. The weight of hexagon, octagonal and new elliptical section is decreased by 7.7and 9.2g / 15.1, respectively, which verifies the feasibility of the program and achieves the optimization effect. This paper has certain guiding significance to the design of telescopic arm in practical engineering.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH213.6

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