钢桁架桥节点塑性破坏机理研究

钢桁架桥节点塑性破坏机理研究(任务书,开题报告,论文16000字)
摘  要
钢结构的节点受力复杂，较为薄弱，在整个结构中起着至关重要的作用，故研究钢结构的节点有一定的意义。本文以钢桁架桥为研究背景，用ANSYS软件建立了钢桁架桥的有限元模型，对其整体进行受力分析，明确各部位受力，并选取关键节点进行三维实体有限元分析，研究该节点塑性破坏的机理，并进行抗塑性破坏设计，通过比较设置加劲肋、粘贴钢板和增加连接板等加固措施，得出最佳的加固方案。
分析结果表明：该钢桁架桥的最大位移发生在跨中位置，位移较小表明结构具有较大的刚度；结构内力的最大值发生在端部，杆件受剪力值较小。通过对关键节点的有限元分析，得到了该节点塑性区的扩展特征：支管与主管连接处首先发生屈服，同时形成塑性区并逐渐向四周扩散，直到节点出现明显的塑性变形后才发生破坏。本文建立了多种加固措施的三维模型，如设置加劲肋、粘贴钢板和增加连接板等，研究表明：加固效果最好的是增加连接板，在同一条件下此方法的最大应力值减少了10.3%，其次是在支管处设置加劲肋，最大应力值减少了6.5%，而粘贴钢板的效果最差，仅减少了0.9%。
关键词：钢桁架桥；整体节点；有限元分析；塑性破坏；加固措施 [资料来源：http://doc163.com]
Abstract
The joints of steel structures are complex and weak, and play a vital role in the whole structure. Therefore, it is of certain significance to study the nodes of steel structures. In this paper, the steel truss bridge is taken as the research background. The finite element model of steel truss bridge is established by ANSYS software. The whole force is analyzed, the force of each part is determined, and the key nodes are selected for 3D solid finite element analysis. The mechanism of plastic failure, and the design of anti-plastic failure, the best reinforcement scheme is obtained by comparing the reinforcement measures such as stiffeners, steel plates and connecting plates.
The analysis results show that the maximum displacement of the steel truss bridge occurs at the mid-span position, and the smaller displacement indicates that the structure has greater stiffness; the maximum internal force of the structure occurs at the end, and the shearing force of the rod is small. Through the finite element analysis of the key nodes, the extended feature of the plastic zone of the joint is obtained: the joint between the branch pipe and the main pipe first yields, and the plastic zone is formed and gradually spreads to the periphery until the node undergoes obvious plastic deformation. In this paper, three-dimensional models of various reinforcement measures are established, such as setting stiffeners, pasting steel plates and adding joints. Research shows that the best reinforcement effect is to increase the joint value. Under the same conditions, the maximum stress value of this method is reduced by 10.3 %, followed by the provision of stiffeners at the branch, the maximum stress value was reduced by 6.5%, and the effect of the bonded steel plate was the worst, only 0.9%. [资料来源：www.doc163.com]
Keywords:Steel truss bridge; Integral joints; Finite element analysis; Plastic failure; Reinforcement measures
目录
第1章绪论    1
1.1研究背景    1
1.1.1选题背景及意义    1
1.1.2整体节点概述    1
1.2国内外研究现状    2
1.3主要内容及研究方法    4
1.3.1主要内容    4
1.3.2研究方法    4
1.4论文框架    5
第2章非线性理论与有限元法    6
2.1概述    6
2.2几何非线性问题    6
2.3材料非线性问题    7
2.4 ANSYS有限元软件介绍    10
2.4.1 ANSYS优势    10
2.4.2 APDL简介    11
2.4.3非线性分析    11
2.5本章小结    11
第3章钢桁架桥静力分析    13
3.1结构体系与设计参数    13
3.2钢桁架桥结构分析计算    13 [来源：http://Doc163.com]
3.2.1分析内容    13
3.2.2计算模型    14
3.2.3荷载效应    15
3.2.4结构静力分析计算    15
3.3本章小结    22
第4章节点有限元模型建立    23
4.1研究节点的选取    23
4.2矩形钢管节点承载力计算    23
4.3有限元模型建立过程    24
4.3.1单元选取    24
4.3.2本构关系    25
4.3.3网格划分    25
4.3.4边界条件和耦合情况    26
4.4本章小结    27
第5章节点塑性破坏机理分析    28
5.1节点受力分析    28
5.1.1塑性区的扩展情况    28
5.1.2荷载位移曲线    30
5.2本章小结    30
第6章节点抗塑性破坏设计    32
6.1加劲肋的设置对节点应力的影响    32
6.2粘贴钢板对节点应力的影响    33