正放四角锥网架结构连续倒塌机理与抗倒塌设计研究

发布时间：2018-11-05 17:29

【摘要】：近年来自然灾害频频来袭，建筑经常会遭受到暴风、大雪的威胁。由于网架结构应用的广泛性及使用功能的特殊性，一旦在意外荷载作用下发生连续倒塌，将会给社会生产和人民生命财产安全造成及其重大的损失。因此，对网架结构抗连续性倒塌的研究具有重大意义和深远影响。对于网架结构的抗连续倒塌性能研究主要围绕如下两个方面：（1）已有的网架结构是否拥有足够的承载能力，确保在意外荷载作用下不发生连续性倒塌；（2）如何利用科学合理的设计理念及方法设计出能够抵抗连续性倒塌发生的网架结构体系。本文以重要杆件失效为前提，以数值模拟与模型试验相结合的方式，，从正放四角锥网架结构连续倒塌机理出发研究了如下三个核心问题：（1）正放四角锥网架结构杆件重要性评价方法研究；（2）基于重要构件失效的正放四角锥网架结构连续倒塌机理研究；（3）正放四角锥网架结构抗连续倒塌设计方法研究。针对网架结构杆件众多的特点，本文将结构体系的能量变化率与杆件的响应变化率结合起来，提出了基于概念判断的正放四角锥网架结构杆件重要性评估方法，并验证了判断方法的适用性。在四角锥网架结构缩尺模型重要杆件上设计了初始失效引入装置，进行了重要构件失效情况下的动力倒塌试验，并基于ANSYS/LS-DYNA有限元分析平台重现了试验模型的连续倒塌过程，探索了四角锥网架结构发生连续性倒塌的力学机理，同时验证了数值分析的准确性。基于ANSYS/LS-DYNA有限元分析平台，对四角锥网架结构实体模型分别进行了单根、多根重要构件失效情况下的倒塌分析。从结构体系的失效特征、内力重分布规律及抗倒塌承载力等方面揭示了正放四角锥网架结构发生连续性倒塌的力学机理，并以此为依据，提出了基于压杆稳定的抗连续倒塌设计方法，且验证了该方法的有效性。
[Abstract]:In recent years, natural disasters frequently come, buildings are often threatened by storm and heavy snow. Because of the wide application of grid structure and the particularity of its use function, once it collapses continuously under the action of accidental load, it will cause great losses to social production and the safety of people's life and property. Therefore, it is of great significance and far-reaching influence to study the continuous collapse of truss structures. The research on the continuous collapse resistance of the truss structure is mainly focused on the following two aspects: (1) whether the existing truss structure has enough bearing capacity to ensure that the continuous collapse does not occur under the unexpected load; (2) how to use the scientific and reasonable design idea and method to design the truss structure system which can resist the continuous collapse. On the premise of failure of important members, this paper combines numerical simulation with model test. The following three key problems are studied based on the continuous collapse mechanism of forward position tetragonal conical truss structure: (1) study on the evaluation method of the importance of the truss member of the forward position tetragonal conical truss structure; (2) study on the mechanism of continuous collapse of forward position tetragonal truss structure based on failure of important components; (3) study on design method of anti-continuous collapse of forward position tetragonal conical grid structure. In view of the large number of truss members, this paper combines the energy change rate of the structure system with the response change rate of the truss, and puts forward a method for evaluating the importance of the truss members of the space grid truss based on the concept judgment. The applicability of the method is verified. The initial failure introducing device is designed on the important member of the scale model of the tetragonal conical truss structure, and the dynamic collapse test is carried out under the condition of the failure of the important member. Based on the ANSYS/LS-DYNA finite element analysis platform, the continuous collapse process of the test model is reproduced, and the mechanical mechanism of the continuous collapse of the tetragonal conical truss structure is explored, and the accuracy of the numerical analysis is verified. Based on the ANSYS/LS-DYNA finite element analysis platform, the collapse analysis of the solid model of tetragonal conical truss structure is carried out under the condition of failure of one or more important members. From the failure characteristics of structural system, internal force redistribution law and anti-collapse bearing capacity, this paper reveals the mechanical mechanism of the continuous collapse of the space truss structure with quadrilateral cones, which is based on the failure characteristics, the internal force redistribution law and the anti-collapse bearing capacity, etc. A design method for continuous collapse resistance based on compression rod stability is proposed, and the effectiveness of the method is verified.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU356

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