基于向量式有限元的ETFE气枕找形与荷载态分析

发布时间：2018-03-24 05:15

本文选题：气枕结构　切入点：向量式有限元　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：随着ETFE气枕结构作为国家游泳中心的外围护系统在我国首次应用，，其诸多特点和突出优势得到认识和验证，推动了ETFE充气膜结构在我国建筑领域的应用和发展，使其作为新型建筑围护体系相继出现在广州南站和大连体育场等大型大跨空间结构中。然而，在建筑技术高速发展的今天，相比于张拉膜结构，我国对ETFE充气膜结构的认识与研究还相对缺乏，亦没有正式的气枕结构系统规范，其应用还处于比较初级的阶段。既有的膜结构找形与和荷载分析方法主要有力密度法、动力松弛法和非线性有限元法，而气枕结构的分析研究又以非线性有限元法为主。气枕作为柔性结构在荷载作用下必然产生大变形大转动，刚体位移与弹性变形共存，表现出很强的几何非线性，传统有限元在处理此类问题时有较多限制。向量式有限元是以向量力学为理论基础并结合数值计算被提出的一种新颖的结构行为分析方法，其能有效处理机构运动、弹塑性、大变形、大变位、断裂、碰撞以及倒塌等强非线性问题或不连续行为，表现出很强的适应性。基于以上研究背景本文将向量式有限元引入到气枕结构的找形与和荷载分析，探讨了向量式有限元法处理气枕结构问题的可行性与有效性。论文先详细概括了膜结构三阶段分析及比较了既有三种数值分析方法。通过推导最为简单的杆单元理论公式，引出并较为详细地阐明了向量式有限元的基本原理和分析步骤，编制了杆单元计算程序分析了桁架静力和机构运动问题，并用于索网结构的找形分析，验证了向量式有限元杆单元公式和程序的可行性和准确性。进一步推导了向量式有限元三节点三角形常应变膜单元理论公式，编制了膜单元计算程序，通过模拟气囊充气问题验证了膜单元公式以及所编程序的可行性与有效性。将向量式有限元膜单元理论应用于气枕结构的找形分析，完善计算程序，阐明分析步骤，对正三角形、矩形及正六边形气枕结构进行了找形分析，并与ANSYS结果对比分析，充分验证了用向量式有限元方法于气枕结构找形的适用性与有效性。在找形分析基础上，将向量式有限元进一步应用于气枕结构的荷载分析，选取矩形气枕分析了5种常见荷载工况下的静力行为，与ANSYS结果对比分析，验证了向量式有限元方法用于气枕结构荷载分析的可行性与有效性。
[Abstract]:With the first application of the ETFE air cushion structure as the outer enclosure system of the national swimming center in China, its many characteristics and outstanding advantages have been recognized and verified, which has promoted the application and development of the ETFE aerated membrane structure in the field of architecture in our country. As a new type of building enclosure system, it appears in large span space structures such as Guangzhou South Railway Station and Dalian Stadium one after another. However, with the rapid development of building technology today, compared with the tensioning membrane structure, The understanding and research of ETFE aerated membrane structure is still relatively lacking, and there is no formal specification for the air pillow structure system, and its application is still in the primary stage. The existing methods of form-finding and load analysis of membrane structures are mainly force density method. Dynamic relaxation method and nonlinear finite element method, and the nonlinear finite element method is the main method for the analysis of the air pillow structure. As a flexible structure, a large deformation and a large rotation will occur, and the rigid body displacement will coexist with the elastic deformation. Because of its strong geometric nonlinearity, the traditional finite element method has many limitations in dealing with this kind of problems. The vector finite element method is a new structural behavior analysis method based on the theory of vector mechanics and numerical calculation. It can effectively deal with the mechanism motion, elastic-plastic, large deformation, great displacement, fracture. Strong nonlinear problems or discontinuous behaviors such as collision and collapse show strong adaptability. Based on the above research background, this paper introduces the vector finite element method to the shape finding and load analysis of the air pillow structure. The feasibility and effectiveness of vector finite element method (VFEM) in dealing with the problem of air pillow structure are discussed. Firstly, the three-stage analysis of membrane structure and the comparison of three existing numerical analysis methods are summarized in detail. The basic principle and analysis steps of the vector finite element method are introduced and explained in detail. The bar element calculation program is compiled to analyze the static force and mechanism motion of the truss, and it is used for the shape finding analysis of the cable-net structure. The feasibility and accuracy of vector finite element element formula and program are verified. Furthermore, the theoretical formula of the three-node triangular constant strain membrane element with vector finite element is derived, and the calculation program of the membrane element is compiled. The feasibility and validity of the membrane element formula and the program are verified by simulating the air bag inflating problem. The vector finite element membrane element theory is applied to the shape finding analysis of the air pillow structure, the calculation program is perfected, and the analysis steps are expounded. In this paper, the shape finding of the triangular, rectangular and hexagonal air pillow structures is analyzed and compared with the results of ANSYS. The applicability and validity of the vector finite element method in finding the shape of the air pillow structure are fully verified. On the basis of shape finding analysis, the vector finite element method is further applied to the load analysis of air cushion structure. The static behavior of five common load conditions is analyzed by selecting rectangular air cushion, and the results are compared with ANSYS results. The feasibility and validity of vector finite element method for load analysis of air cushion structures are verified.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU353

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