复合材料在海洋钢结构加固修复中的应用研究

发布时间：2018-04-17 20:49

本文选题：CFRP + 断裂力学　；参考：《中国舰船研究院》2015年硕士论文

【摘要】：目前世界各地在役的基础设施中存在大量的金属工程结构,这些结构在长期的环境载荷和工程载荷的共同作用下,容易产生各种问题,需要对其进行修复和加固。以往经常使用的加固方法为焊接加固法,即在待加固结构上焊接钢盖板或其他型材。目前焊接加固法已经发展较为成熟,得到广泛的运用,但同时也存在许多问题,如焊接后结构局部组织脆化、残余应力较高、焊接质量受环境及操作人员的影响等。而用复合材料加固修复钢结构作为一种全新的方法,以其高强度、高弹性模量、良好的耐腐蚀性、耐久性、耐疲劳性等优点越来越受到工程界的重视。目前复合材料加固修复钢结构技术已经在土木工程领域和航空航天领域得到一定的应用,而在船舶与海洋结构上的应用和研究尚少。系统的加固设计方法和疲劳加固设计方法仍然有待进一步的试验研究和理论分析。本论文首先对复合材料加固各种类型钢结构的加固特点和研究现状以及本文研究中涉及的理论知识(复合材料经典层合板理论、加固板裂纹尖端应力强度因子计算方法、Dugdale大范围塑性断裂力学模型等)进行了阐述。通过Dugdale的大范围塑性断裂力学模型,以钢材屈服为标准,以加固后构件承载能力不低于无损伤构件的承载能力为目标,确定了加固量的取值。在已有理论研究的基础上,结合有限元方法,确定了有效粘贴长度、有效粘贴宽度、铺层设计这几个加固参数的取值。通过前章对加固量、相关加固参数的计算确定静态拉伸试验试件制作方案。通过静态拉伸试验探究了加固试件的破坏过程、破坏形式。通过对位移-载荷曲线、破坏形态和特征载荷的分析验证了加固量和加固参数的有效性。通过计算加固板裂纹尖端应力强度因子并结合Paris公式,预估疲劳载荷下试件的剩余寿命。通过单侧加固和双侧加固的疲劳试验检验剩余疲劳寿命计算方法的准确性。对CFRP加固钢板的环境耐受性进行了试验研究,探究了CFRP加固钢板的防腐蚀作用和环境因素对粘结性能的影响。
[Abstract]:At present, there are a large number of metal engineering structures in the existing infrastructure all over the world. Under the combined action of long-term environmental load and engineering load, these structures are easy to produce various problems, which need to be repaired and strengthened.In the past, welding reinforcement method is often used, that is, welding steel cover plate or other section on the structure to be strengthened.At present, welding reinforcement method has been developed and widely used, but there are also many problems, such as local structure embrittlement after welding, high residual stress, welding quality affected by environment and operator, etc.As a new method, steel structures strengthened with composite materials have been paid more and more attention by the engineering field for their high strength, high elastic modulus, good corrosion resistance, durability, fatigue resistance and so on.At present, composite material reinforcement and repair of steel structures has been applied in the field of civil engineering and aerospace, but the application and research in ships and marine structures is still few.The reinforcement design method and fatigue reinforcement design method of the system still need further experimental research and theoretical analysis.In this paper, firstly, the characteristics and research status of various types of steel structures strengthened with composite materials and the theoretical knowledge involved in this study (classical laminate theory of composite materials) are discussed.The calculation method of stress intensity factor at crack tip of strengthened slab is described in this paper, such as Dugdale's large range plastic fracture mechanics model and so on.Based on the large range plastic fracture mechanics model of Dugdale, taking steel yield as the standard and the bearing capacity of strengthened members not lower than that of non-damaged members as the goal, the value of strengthening amount is determined.Based on the existing theoretical research and the finite element method, the effective bonding length, the effective paste width and the reinforcement parameters of layering design are determined.In the previous chapter, the static tensile test specimen was made by calculating the reinforcement quantity and the relative reinforcement parameters.The failure process and failure form of the strengthened specimens were investigated by static tensile test.Through the analysis of displacement-load curve, failure form and characteristic load, the validity of reinforcement quantity and reinforcement parameters is verified.By calculating the stress intensity factor at the crack tip of the strengthened plate and combining the Paris formula, the residual life of the specimen under fatigue load is predicted.The accuracy of residual fatigue life calculation method is verified by fatigue tests of unilateral and bilateral reinforcement.The environmental tolerance of steel plate strengthened by CFRP was studied. The corrosion resistance of steel plate strengthened by CFRP and the influence of environmental factors on the bond properties were investigated.
【学位授予单位】：中国舰船研究院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P75

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