FRP-钢板复合材料基本力学性能和耐久性能研究

发布时间：2018-09-17 08:14

【摘要】：纤维增强聚合物(Fiber Reinforced Polymer,简称FRP)具有轻质、高强等优点被广泛应用于结构的补强加固。但是,FRP加固后的结构脆性性能显著,不利于结构抗震。本文结合国家自然科学基金项目(51108355)和湖北省自然科学基金项目(2011CDB269),提出了一种新型复合材料,即采用FRP与钢板混杂铺设形成FRP-钢板复合材料。这种新型复合材料可以充分发挥FRP与钢板力学性能的互补性,显著地改善单一加固材料的强度、延性和刚度。本文研究了FRP-钢板复合材料静力拉伸性能、温度作用下FRP-钢板复合材料的静力拉伸性能、温度作用下FRP与钢板的界面粘结性能、FRP-钢板复合材料在干湿交替老化作用下的耐久性能,主要包括以下几个方面： 1、对36个制作的FRP-钢板复合材料试件进行静力拉伸试验。研究FRP-钢板复合材料的基本力学性能,影响因素包括：纤维种类(碳纤维、玻璃纤维和玄武岩纤维)、纤维铺设层数、钢板厚度以及纤维铺设方式。研究结果表明：(1)CFRP与钢板混杂铺设形成的CFRP-钢板复合材料不但具有较高的强度,而且具有较好的塑性性能；GFRP与钢板混杂铺设形成的GFRP-钢板复合材料在钢板屈服后具有较好的延性性能；(2)当FRP铺设层数一定时,随着钢板厚度的增加,FRP-钢板复合材料的基本力学性能增强,但是增强幅度逐渐降低,当钢板厚度超过4mm时,降低速度增大；(3)FRP与钢板的铺设方式越对称、均匀,FRP-钢板复合材料受力性能越好。根据试验结果,采用复合材料力学中的混合法则,本文建立了FRP-钢板复合材料的应力-应变关系模型,理论计算值与试验值吻合较好。 2、对66个在30℃‖120℃温度作用下的CFRP-钢板复合材料和GFRP-钢板复合材料进行了静力拉伸试验。试验结果表明：随着温度升高,FRP-钢板复合材料的基本力学性能降低,在粘结胶体的玻璃化转化温度50℃附近降低速率较大。根据试验结果,本文分别提出了温度作用下,FRP-钢板复合材料弹性模量、钢板屈服后模量、屈服强度和纤维断裂强度计算公式,计算结果与试验结果吻合较好。 3、通过153个FRP与钢板的双向剪切试件,研究温度范围30℃～120℃作用下FRP与钢板的界面粘结性能。根据研究目的不同,采用两种FRP与钢板双向剪切模型进行试验研究。(1)FRP与钢板的双向剪切模型Ⅰ试验结果表明：1)随着温度升高,FRP与钢板双向剪切模型Ⅰ试件的破坏模式发生转变；2)随着温度升高,FRP与钢板双向剪切模型Ⅰ试件的极限强度和粘结刚度逐渐降低,在粘结胶体的玻璃化转化温度附近降低速率较大。根据试验结果,结合粘结胶体在温度作用下的力学性能退化关系,采用修正的Arrhenius(阿伦尼乌斯)方程,本文提出了FRP与钢板粘结刚度退化计算公式,计算结果与试验结果吻合较好。(2)FRP与钢板的双向剪切模型Ⅱ试验结果表明：1)随着温度升高,FRP与钢板双向剪切模型Ⅱ试件的极限强度降低；2)温度作用下,FRP与钢板双向剪切模型Ⅱ试件的破坏模式主要是FRP与钢板的剥离破坏；3)在研究FRP与混凝土粘结界面成果的基础上,本文建立了不同温度作用下FRP与钢板粘结剪应力-滑移关系模型,并提出了不同温度作用下,FRP与钢板粘结极限承载力计算公式,并将计算值与试验值对比,结果表明吻合较好。 4、通过120个试件研究干湿交替作用下CFRP-钢板复合材料的耐久性能。试验结果表明：(1)干湿交替作用对单侧铺设CFRP-钢板复合材料的屈服强度、纤维断裂强度影响较大,对弹性模量和钢板屈服后模量影响较小；(2)干湿交替作用对双侧铺设CFRP-钢板复合材料的屈服强度、纤维断裂强度、弹性模量以及纤维屈服后模量均有较大影响；(3)双侧铺设CFRP-钢板复合材料的力学性能退化速率高于单侧铺设CFRP-钢板复合材料。根据试验结果,本文建立了在干湿交替作用下CFRP-钢板复合材料静力拉伸性能计算模型,对CFRP-钢板复合材料在干湿交替环境下的基本力学性能损失进行预测分析,模型计算结果与试验结果吻合较好。本文提出了CFRP-钢板复合材料纤维断裂强度计算模型对CFRP-钢板复合材料在干湿交替环境下的使用寿命进行预测分析。
[Abstract]:Fiber Reinforced Polymer (FRP) is widely used in structural reinforcement because of its lightweight, high strength and other advantages. However, the brittleness of the structure strengthened by FRP is remarkable, which is not conducive to the seismic performance of the structure. A new kind of composite material, FRP-steel plate composite material, is developed by mixing FRP and steel plate. This new composite material can give full play to the complementarity of mechanical properties between FRP and steel plate and significantly improve the strength, ductility and stiffness of a single reinforcement material. The static tensile properties of FRP-steel sheet composites, the interfacial bond between FRP and steel sheet under temperature, and the durability of FRP-steel sheet composites under alternate wet-dry aging mainly include the following aspects:
1. Static tensile tests were carried out on 36 FRP-steel composite specimens. The basic mechanical properties of FRP-steel composite were studied. The influencing factors included fiber types (carbon fiber, glass fiber and basalt fiber), fiber layers, steel plate thickness and fiber laying methods. The CFRP-steel sheet composites formed by laying not only have higher strength but also better plasticity; the GFRP-steel sheet composites formed by mixing GFRP and steel sheet have better ductility after yield; (2) When the number of layers of FRP is fixed, with the increase of the thickness of steel sheet, the FRP-steel sheet composites are basically the same. The mechanical properties of FRP-steel sheet composites are enhanced, but the extent of reinforcement decreases gradually, and the reduction rate increases when the thickness of steel sheet exceeds 4 mm. (3) The more symmetrical and uniform the laying mode between FRP and steel sheet, the better the mechanical properties of FRP-steel sheet composites. According to the experimental results, the stress-stress of FRP-steel sheet Composites is established by using the mixing rule in composite mechanics. The theoretical value is in good agreement with the experimental data.
2. Static tensile tests were carried out on 66 CFRP-steel plate composites and GFRP-steel plate composites at 30 120 C. The results show that the basic mechanical properties of FRP-steel plate composites decrease with the increase of temperature, and the glass transition temperature of bonding colloid decreases greatly near 50. In this paper, the formulas for calculating the elastic modulus, post-yield modulus, yield strength and fiber fracture strength of FRP-steel sheet composites under the action of temperature are presented. The calculated results are in good agreement with the experimental results.
3. The interfacial bonding between FRP and steel sheet was studied by 153 specimens of FRP and steel sheet under the temperature range of 30 ~120 C. According to different research purposes, two kinds of two-way shear models were used to study the interfacial bonding between FRP and steel sheet. The ultimate strength and bond stiffness of FRP and steel plate bi-directional shear model I specimens decrease gradually with the increase of temperature, and the rate of decrease is larger near the glass transition temperature of bond colloid. According to the test results, the mechanical properties of bond colloid under the action of temperature are combined. Based on the modified Arrhenius equation, a formula for calculating the degradation of bond stiffness between FRP and steel plate is presented. The results are in good agreement with the experimental results. (2) The experimental results of two-way shear model II of FRP and steel plate show that: 1) the ultimate strength of two-way shear model II decreases with the increase of temperature. The failure modes of FRP and steel plate bi-directional shear model II specimens are mainly the peeling failure of FRP and steel plate under the action of temperature; 3) Based on the study of the results of the bond interface between FRP and concrete, the bond shear stress-slip relationship model of FRP and steel plate under the action of different temperatures is established, and the bond shear stress-slip relationship between FRP and steel plate under the action of different temperatures is proposed. The formula for calculating ultimate bearing capacity of steel plate is calculated, and the calculated value is compared with the experimental value.
4. The durability of CFRP-steel sheet composites was studied by 120 specimens under alternating wetting and drying. The results show that: (1) alternating wetting and drying have great influence on the yield strength and fiber fracture strength of unilateral CFRP-steel sheet composites, but little influence on elastic modulus and post-yield modulus of steel sheet; (2) alternating wetting and drying have great influence on both sides of the composites. The yield strength, fiber breaking strength, elastic modulus and post-yield modulus of CFRP-steel sheet composites have great influence. (3) The degradation rate of mechanical properties of CFRP-steel sheet composites with both sides is higher than that of CFRP-steel sheet composites with one side. The calculation model of static tensile properties of CFRP-steel plate composites is used to predict and analyze the basic mechanical properties loss of CFRP-steel plate composites under alternating wet and dry environments. The calculated results of the model are in good agreement with the experimental results. Prediction and analysis of service life under the environment.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU599

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