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1、 硕士学位论文工程起重机中超静定桁架结构的弹性稳定性分析THE ELASTIC STABILITY ANALYSISOF INDETERMINATE TRUSS STRUCTUREIN CONSTRUCTION CRANE胡燕东哈尔滨工业大学2010年 6月 国内图书分类号：TH113; TH21国际图书分类号：621.873; 621.01学校代码：10213密级：公开工学硕士学位论文工程起重机中超静定桁架结构的弹性稳定性分析硕士研究生：胡燕东导 师：兰朋副教授申请学位：工学硕士学科：机械设计及理论所在单位：机电工程学院答辩日期： 2010年 6月授予学位单位：哈尔滨工业大学 Classif
2、ied Index : TH113; TH21U.D.C.: 621.873; 621.01Dissertation for the Master Degree in EngineeringTHE ELASTIC STABILITY ANALYSISOF INDETERMINATE TRUSS STRUCTUREIN CONSTRUCTION CRANECandidate：Hu Yan DongSupervisor：Ass. Prof. Lan PengAcademic Degree Applied for：Specialty：Master of EngineeringMechanical D
3、esign and Theory School of Mechatronics Engineering June, 2010Affiliation：Date of Defence：Degree-Conferring-Institution： Harbin Institute of Technology 摘要摘要桁架钢结构具有重量轻、承受压力和弯矩能力大的特点，广泛应用于重载高耸的机械结构和建筑结构中，如塔式起重机的塔身、吊臂，施工升降机的导轨架等。由于这些结构的可靠性直接决定了设备安全性，相关的规范中对其强度、刚度和稳定性要求极高。高耸结构本身及其组成杆件均为细长结构，稳定性计算在设计中尤显突
4、出。随着材料科学的迅猛发展，高强度结构钢开始广泛应用于承载力尽量大、质量尽量轻的钢结构中，此时相对于结构的强度和刚度验算而言，起重机金属结构稳定性分析的重要性愈加凸显，也是本文的主要研究内容。目前有限元法是计算大型桁架结构的最有效方法。但是用有限元软件分析工程中的超静定桁架结构时经常会碰到局部失稳而整体不失稳的情况，有限元软件分析误认为局部失稳临界力是结构失稳时的临界载荷，而且有时整体结构真实失稳临界力远大于局部失稳临界力。在工程中设计人员更关心结构实际能够承受的稳定临界载荷，即整体结构何时出现失稳，它是确定结构稳定性的安全储备、优化结构设计的依据。因此整体结构失稳临界载荷的确定成为稳定设计的
5、首要问题。本文讨论了桁架结构发生失稳两种不同形式：杆系失稳和单肢失稳。研究了桁架结构发生杆系失稳和单肢失稳的原因，以及与结构整体失稳关系。提出了当结构的参数变化时两种失稳形式可以相互转化的联系。根据结构稳定性分析的有限元理论，运用精确有限元理论的单元刚度矩阵来分析桁架结构的稳定性问题，推导了桁架结构临界失稳的判别式。结合判别式从理论上阐述了结构发生失稳的两种不同类型，并解释了有限元软件分析超静定桁架结构稳定性出现误判的原因。根据杆件稳定性理论提出了解决有限元软件误判的方法，并且基于上述方法编写了基于软件 ANSYS的稳定性分析程序来分析一般桁架结构的稳定性，获得桁架结构真实的临界失稳载荷，以供
6、工程人员在结构设计和校核中使用和借鉴。运用本文编写的稳定性分析程序对 STL80型塔式起重机的塔身进行结构稳定性分析。探讨了塔身高度、风载、倾覆弯矩等因素对塔身稳定性的影响，并校核了STL80型塔式起重机在工作情况下塔身的稳定性。关键词：超静定桁架；有限元；整体失稳；局部失稳- I - 哈尔滨工业大学工学硕士学位论文AbstractSteel truss with light weight, large capacity of pressure and bending moment, iswidely used in heavy mechanical structure and high-ri
7、se building structures, such astower cranes tower, crane, construction elevator guide rail racks. Because these structuresdirectly determines the reliability of the equipment safety, the relevant specifications ofits strength, stiffness and stability is highly demanding. High-rise structure and itsc
8、omponent bars are slender structure, stability calculation in the design is utmostimportant. With the rapid development of materials science, high-strength structural steelhave been widely used in steel structure which bearing capacity as large as possible,quality of light as far as possible, at thi
9、s point, relative to the structural strength andrigidity checking, Crane metal structure increasingly highlighted the importance ofstability analysis which is also the main contents of this article.Currently large-scale finite element method is to the most effective way calculatetruss structure. How
10、ever, the finite element analysis of statically indeterminate trussstructures in engineering software often encountered that the overall is stable but localunstable, analysis of finite element software mistakenly believe that the critical localbuckling strength is the critical load of structural ins
11、tability, and sometimes the overallstructure of the critical buckling force is much larger than the real critical force of localbuckling. Designers in the project is more concerned about the stability of the structure towithstand the actual critical load, that is when the structure overall buckling
12、occurs. It isthe basis to determine the structural stability of the safety margin, optimize the structuredesign. Thus the how to determine the critical buckling load of the overall structure is themost important issue of stability design.This article discusses two different forms of instability in t
13、he truss structure: trussbuckling and single-limb buckling. In this paper, the reason of the instabilities and theconnection between these instabilities and overall buckling of the structure are researched.The connection of the two kinds of buckling transformed into each other when thestructure para
14、meters are changed is proposed.According to stability analysis of finite element theory, the discriminant of trussstructure critical instability is derived by using accurate finite element theory to analyzethe stability problem of truss element stiffness matrix. Combined with the discriminantthe two
15、 different types of structure buckling is described, and the reason of the mistakenin finite element analysis of statically indeterminate truss structure stability is explained.According to the stability theory of rods, the method to resolve the mistaken in finiteelement software is proposed.- II - 哈尔滨工业大学工学硕士学位论文Based on the above method, stabili
