CFRP加固圆形钢管抗压承载力研究

以碳纤维增强复合材料(CFRP)加固长圆形钢管轴心受压试验结果为基础,分析了CFRP在加载过程中的力学行为并提出了CFRP的破坏与加固机理。考虑初偏心、材料和几何非线性的影响,建立了一个预测承载力、轴向和横向位移的纤维模型,分析了CFRP的有效抗压弹性模量与CFRP层数的变化关系。将有效抗压弹性模量应用于有限元模型中进行加载试验模拟,验证简化纤维模型的合理性。结果表明:在达到极限承载力之前,圆形钢管轴心受压构件中部全截面均表现为压应变,验证了提出的加固机理; 随着CFRP层数的增加,CFRP的有效抗压弹性模量按自然对数增长; 有效抗压弹性模量的引入较好地模拟了CFRP加固钢管的受压机理,并且纤维模型计算结果与有限元模型计算结果吻合良好; 随着加载偏心距增大,CFRP对长轴压构件承载力的贡献率逐渐降低,因此对于此类加固构件的使用应该尽量减小加载偏心距,以充分利用CFRP的抗压强度。

Research on Compressive Carrying Capacity of Circular Steel Tubes Strengthened with Carbon Fiber Reinforced Polymer

Based on the test results of axial compression of long circular steel tube strengthened with carbon fiber reinforced polymer(CFRP), the mechanical behavior of CFRP in the loading process was analyzed, and the failure and reinforcement mechanism of CFRP were proposed. Considering the effects of initial eccentricity, material and geometric nonlinearity, a fiber model was established to predict the bearing capacity, axial and lateral displacements of CFRP. The relationship between the effective compressive elastic modulus of CFRP and the number of CFRP layers was analyzed. The effective compressive elastic modulus was applied to the finite element model to simulate the loading test, and the rationality of the simplified fiber model was verified. The results show that before the ultimate bearing capacity is reached, the central section of the circular steel tube axial compression member shows compressive strain, which verifies the proposed reinforcement mechanism. With the increase of CFRP layers, the effective compressive elastic modulus of CFRP increases according to natural logarithm. The introduction of effective compressive elastic modulus well simulates the compression mechanism of CFRP strengthened steel pipe, and the calculation results of fiber model are in good agreement with those of finite element model.With the increase of loading eccentricity, the contribution rate of CFRP to the bearing capacity of long axial compression members gradually decreases. Therefore, the loading eccentricity should be reduced as much as possible to make full use of the compressive strength of CFRP.