【作者】 马青；

【导师】 赵福令；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2009， 硕士

【摘要】 随着工程建设发展的需要,起重机日益向着大型、高耸、轻柔化、格构式方向发展。由于高强度钢材的大量采用,提高了结构强度,却使刚度和稳定性问题日显突出。复杂桁架式结构的稳定性分析成为当代大型起重机结构设计计算的难点。由于履带起重机臂架系统为空间桁架结构,且主臂和副臂轴多有夹角,利用传统的数学模型和力学方法已经很难对其稳定性进行准确的校核。随着现代力学方法和计算机技术的发展,大型的商用有限元分析软件被引入到起重机的设计计算中。其中ANSYS是应用最为广泛,通用性最好的一款有限元软件,但目前国内外在对ANSYS的应用上,通常按照臂架实际结构进行建模,在臂架较长的情况下或者建立多种长度的臂架模型时,建模工作十分繁琐,耗时耗力。针对上述存在的现实问题,本文充分分析研究履带起重机桁架臂的结构特点,深入研究臂架系统的有限元模型简化、ANSYS线性屈曲分析及非线性稳定性分析、ANSYS二次开发技术和VB编程技术等,论文的主要研究工作和研究成果具体如下:(1)分析履带起重机桁架臂的工作原理、结构特点和受力情况,了解已有的建模工作中出现的工作量大、模型不易修改等问题,确定臂架有限元模型简化的必要性和可行性。(2)研究如何利用有限元分析软件ANSYS进行结构稳定性分析,包括线性屈曲分析和非线性稳定性分析。(3)根据臂架的整体结构特点,确定桁架臂在ANSYS中的模型简化方案,选择变截面梁单元,对臂架惯性矩进行等效计算,改进臂架各部分铰点的连接方式,并通过比较复杂模型和简化模型的屈曲特征值误差,确定简化方案的正确性。(4)分析臂架的实际受力特点和线性屈曲分析的不足之处,对有限元简化模型进行非线性稳定性分析,得出臂架变形和受力大小之间的关系曲线。(5)开发履带起重机臂架稳定性分析系统,该系统封装了稳定性分析所用到的所有ANSYS命令,用户只需输入设计变量值即可,软件会自动调用ANSYS进行批处理分析,并保存计算结果。更多还原

【Abstract】 With the development demand of construction, the crane is increasingly prone to large-sized, dominant-mountain and with lattice. With enormous use of high-strength steel material, the structure is strengthened, but the problems of structural stiffness and stability inevitablely occurs. So the stability analysis of complicated lattice structure becomes the crux of contemporary and large cranes’ structure design and its calculation. Because of the lattice structure of the crane boom system and the angle between the boom and jib, it is very difficult to accurately calculate the overall stability with the traditional math-model and mechanics method.With the development of modern mechanics methods and computer technology, many practical commercial finite element analysis software were introduced to the crane design calculations. ANSYS as one of the best is used widely. However, at home and abroad, when applying of ANSYS, the establishment of finite model is usually in accordance with the actual structure of the boom system, so that it needs much workload under the condition of long boom or boom with various kinds of length.To solve the problems mentioned above, the author studies the boom structure, the simple finite element model, ANSYS linear buckling analysis and non-linear stability analysis, the active automation technology and the VB programming. The main research work and achievements are as follows:(1) Analyzing the working principle, structure characteristics and force condition of crawler cranes’ truss boom, which makes we know the workload in modeling is very large and the model is not easy to revise, and so on. So, it’s very necessary to simplify the boom finite element model.(2) Studying how to use the finite element analysis software ANSYS, including linear and nonlinear buckling analysis of the stability.(3) In accordance the overall boom structure, confirming the model simplifying method, selecting the variable cross-section beam element, calculating equivalent moment of inertia, improving the boom hinge point connection of all parts. To make sure this simplified method be accurate by comparing the result between truss model and simplified model. (4) Analyzing the actual characteristics of the force and the defects of linear buckling analysis, with the help of which it needs to calculate the stability with the method of nonlinear analysis, and then get the curve of load and deformation.(5) A special software of crawler crane boom system is developed, which encapsulates all the ANSYS operations, so that the users, being free from burdensome modeling, need only concentrate their attention on design variables. The software will automatically call for ANSYS analysis of the batch and save results.更多还原