FRP加固纤维增强混凝土梁承载力的探究

发布时间：2018-05-04 04:28

本文选题：钢筋混凝土梁 + 结构加固　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：纤维增强塑性材料(FRP)在工程中已得到广泛应用。FRP加固技术是指采用高性能环氧树脂胶将纤维增强材料粘结固定于结构的表面,与结构中的材料共同承载,协同工作,可以增大结构的承载力,进而起到结构修补的效果。论文利用有限元程序ANSYS对玻璃纤维增强复合材料(GFRP)加固钢筋混凝土进行研究,建立GFRP加固混凝土梁的计算模型,结合已有实验对加固梁的力学性能进行分析,验证模型的正确性。研究不同初始荷载下GFRP加固混凝土梁的加固效果,当钢筋屈服后用GFRP布对其进行加固,钢筋混凝土梁的承载力仍有明显提高;分析不同载荷下混凝土梁的跨中应力沿梁高度截面上的分布情况。随着载荷增加,受拉区域不断沿高度方向扩展,混凝土受压区域应力呈现非线性,GFRP中应力随之继续增加直至梁体破坏。碳纳米管为一种新兴并具有石墨结晶的纳米材料。其重量轻,并有许多物理及化学机能,需要进一步研究。由于多壁碳纳米管相对于单壁碳纳米管性能好、价格低,作为增强材料已被学者进行研究。将碳纳米管加入混凝土梁中可改善梁的力学特性,碳纳米管混凝土梁的应力、弹性模量等参数根据复合材料力学混合规则的弹性相加理论求出。论文将研究GFRP布加固碳纳米管混凝土梁的承载力情况。复合材料的应力及弹性模量等特性适合于复合体的各部分参数的弹性相加理论。利用ANSYS建立掺入碳纳米管的GFRP加固梁的有限元分析模型,与GFRP加固混凝土梁、未加固的钢筋混凝土梁的对比分析,研究其承载力情况、破坏过程及梁跨中沿截面高度的应力分布情况。分析碳纳米管长径比对碳纳米管增强水泥(混凝土)基应力分布的影响,得出长径比较大时有利于发挥碳纳米管的性能优势,提高复合质料整体的承载能力。
[Abstract]:Fiber reinforced plastic material (FRP) has been widely used in engineering. FRP strengthening technology means that the fiber reinforced material is bonded to the surface of the structure by using high performance epoxy resin adhesive, and it works together with the material in the structure. Can increase the bearing capacity of the structure, and then play the effect of structural repair. In this paper, the finite element program ANSYS is used to study the reinforcement of reinforced concrete (RC) reinforced with glass fiber reinforced polymer (GFRP), and the calculation model of GFRP reinforced concrete beam is established. The mechanical properties of the strengthened beam are analyzed in combination with the existing experiments. Verify the correctness of the model. The reinforcement effect of GFRP reinforced concrete beams under different initial loads is studied. When the steel bars yield and the reinforced concrete beams are strengthened with GFRP cloth, the bearing capacity of the reinforced concrete beams is obviously improved. The distribution of mid-span stress along the beam height section under different loads is analyzed. With the increase of load, the tensile region expands continuously along the direction of height, and the stress in the compressive region of concrete continues to increase until the beam is destroyed. Carbon nanotubes (CNTs) are new materials with graphite crystallization. It is light in weight and has many physical and chemical functions that require further study. Multiwalled carbon nanotubes (MwCNTs) have been studied as reinforcement materials because of their good properties and low price compared with single-walled CNTs. The mechanical properties of concrete beams can be improved by adding carbon nanotubes to concrete beams. The stress and elastic modulus of concrete beams with carbon nanotubes are calculated according to the elastic addition theory of composite mechanical mixing rules. In this paper, the bearing capacity of carbon nanotube concrete beams strengthened with GFRP sheets is studied. The properties of the composite such as stress and elastic modulus are suitable for the elastic addition theory of various parameters of the composite. The finite element analysis model of GFRP strengthened beams with carbon nanotubes was established by using ANSYS. Compared with GFRP reinforced concrete beams and unstrengthened reinforced concrete beams, the bearing capacity of the beams was studied. Failure process and stress distribution in the middle of beam span along section height. The influence of the ratio of length to diameter of carbon nanotubes on the stress distribution of cement (concrete) matrix reinforced by carbon nanotubes is analyzed. It is concluded that when the length and diameter of carbon nanotubes are large, the performance advantages of carbon nanotubes can be brought into play and the overall bearing capacity of composite materials can be improved.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU37

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