碳纤维增强复合材料加固钢结构理论分析和实验研究

合肥工业大学

博士学位论文

碳纤维增强复合材料加固钢结构理论分析和实验研究

姓名：曹靖

申请学位级别：博士

专业：结构工程

指导教师：王建国

2011-04

摘 要

钢结构具有强度高、自重轻、抗震性能好、工业化程度高和可多次利用等优点，是现代工程结构广泛采用的结构形式之一。由于受到制造、施工、使用和环境等多种因素的影响，钢结构中不可避免地存在各种各样的缺陷和损伤，随着结构的使用，材料的微观缺陷逐渐扩展和汇合，导致材料在宏观力学性能方面发生劣化，甚至引发工程事故。因此，研究如何防止钢结构破坏及如何加固修复损伤钢结构，一直是土木工程领域中的一项重要内容。碳纤维增强复合材料（Carbon Fiber Reinforced Polymers，以下简称CFRP）加固修复金属结构是钢结构加固一种新的加固形式和热点。与传统的金属结构加固方法相比，CFRP加固钢结构技术具有许多突出的优点，如不会导致严重的应力集中、不会产生残余应力、施工方便、维护费用低等。因而，CFRP加固修复钢结构是一种高效、具有广阔应用前景的加固技术，涉及到材料学、力学和结构工程等多个领域的知识。

目前CFRP加固混凝土结构技术的研究和应用相对而言比较成熟，但对于CFRP加固金属结构技术的研究和应用还不够系统和完善。本文在总结国内外关于CFRP加固修复钢结构理论分析和试验研究的基础上，对CFRP加固修复钢结构的特殊性及关键问题进行了系统的研究，具体内容安排如下：

由于CFRP加固修复金属结构与混凝土结构加固存在很大的差异，本文对首先CFRP加固修复金属结构的基本问题进行详尽论述，包括粘结机理、影响粘结的因素和CFRP加固后金属结构的工作机理及CFRP加固金属结构的潜在破坏模式。

对CFRP加固金属轴向拉伸构件的界面应力进行分析；对CFRP加固金属单向剪切构件的界面应力进行分析，分析采用断裂力学分析模型，提出粘结强度的计算公式和有效长度的理论计算公式。

对CFRP加固受弯钢梁的界面应力进行分析，推导出CFRP加固修复受弯钢梁的界面剥离应力和剪切应力的计算公式,为下步的试验研究提供理论依据。

采用试验方法对CFRP加固钢结构材料性能进行研究。首先在三坐标测量机上量测出CFRP固化后的厚度，得到粘结层精确厚度；利用温度箱对CFRP线膨胀系数测定，得出该种复合材料在0℃-35℃范围内的线膨胀系数和不同温度下的应变变化；同时测出CFRP在常温下的弹性模量并得到该复合材料的本构关系。

应用正交试验设计对CFRP粘贴钢板的单剪试验进行研究，确定单向剪切试验的粘结长度并和理论公式计算相比较；研究CFRP与钢板粘结面上的应力分布特点、有效粘接长度以及构件破坏的剥离应力；同时分析了CFRP与钢板粘结面上的应力分布特点、粘结剪切破坏过程和破坏特征。

对CFRP片材加固受弯钢梁进行了试验，分别对粘贴一层CFRP布，粘贴三层CFRP布和粘贴CFRP板三种构件进行加载试验；观察试验现象，记录构件的应变和挠度变化情况。

本文提出了“三维实体－桁架－壳元”有限元模型,通过ANSYS有限元方法对CFRP

加固钢结构进行非线性分析；分别对粘贴不同种类CFRP加固工字钢梁的受力性能进行分析，得出了它们的荷载一挠度曲线、极限承载力和变形，并把数值分析结果和试验结果进行对比。

通过对CFRP加固修复钢构件进行进行系统的理论和试验研究得出了若干结论和

建议，充实已有的钢结构加固理论，在工程实践上可以为CFRP加固修复钢结构的设计与施工提供依据。

关键词：CFRP 钢结构加固 断裂力学分析 试验研究 有限元分析

ABSTRACT

Steel structure has high strength, light weight, good aseismic performance, high degree industrialization and repeatedly used etc, and is widely used in modern engineering structure form of structure. Due to the influence of various factors of manufacturing, construction, use and environment, steel structure inevitably exists all kinds of defects and damage.With the structure of the use of structure, material micro defects gradually expanded and rendezvous, causing materials in macroscopic mechanical properties of a place, even trigger engineering accident degradation. Therefore, studying how to prevent steel structure damage and how to reinforce and repair damage steel structure, has been in the field of civil engineering as an important content. The Carbon Fiber Reinforced Polymers (hereinafter referred to as the CFRP) strengthening and repairing the steel structure become a new reinforcement form and hot. Compared to the traditional metal structure reinforcement method, CFRP reinforced steel structure has many outstanding qualities technology, such as won't cause severe stress concentration, won't produce residual stress, construction is convenient, low maintenance fees. Therefore, CFRP reinforcement repair steel structure is a kind of high efficient and has wide prospect of reinforcement technology, involving material science, mechanical and structural engineering and other fields of knowledge.

Currently the research and application of CFRP reinforced concrete structure technology relatively is more mature, but the research and application of CFRP reinforced metal structure technology is ont enough system and perfect. Based on the summarization about CFRP reinforcement and repairing of steel structure theory analysis and experimental research, this paper research the CFRP reinforcement repair steel structure of the specialty and the key problems in the system. Specific content as follows:

Because of the big difference between CFRP metal structure inforcement and CFRP concrete structure inforcement, this paper firstly discussed the basic questions of CFRP reinforcement and repairing metal structure in detail, including bond mechanism, influencing factors of bond and the working mechanism after reinforcement of metal structure and potential failure mode of CFRP reinforced metal structure.

This paper analysis axial tensile component interface stress and one-way shear component interface stress of CFRP reinforced metal structure.By fracture mechanics analysis model, put forward the bonding strength calculation formula and the effective length of theoretical formulas.

By analysis of the interface stress of CFRP reinforced metal beam by deflections, deduce interface stripping stress and shear stress calculation formula of reinforcing plate CFRP reinforced metal beam by deflections, providing the theory basis for the experimental research for next step.

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