基于粘弹性本构的CFRP加固RC梁数值仿真分析

Numerical Simulation Analysis of RC Beams Strengthened with CFRP Using Viscoelasticity Constitutive

为探讨胶黏剂粘弹性对碳纤维增强复合材料(CFRP)加固钢筋混凝土(RC)梁力学行为的影响,以Burger模型表征胶黏剂的应力-应变-时间关系,利用Laplace变换和逆变换推导了Burger模型Prony级数形式的松弛剪切模量;采用ABAQUS对粘贴CFRP加固RC梁进行数值模拟,分析了胶黏剂粘弹性对界面应力、CFRP轴力、RC梁弯矩和加固梁挠度的影响.研究结果表明:胶黏剂的粘弹性对加固梁的力学行为有一定的影响,随着持载时间的增加,界面峰值剪应力和峰值正应力均减小,CFRP轴力减小,RC梁弯矩增大,加固梁挠度增大;当胶层厚度为0.2 mm时,加载30 d后,界面峰值剪应力减小了40.1%,界面峰值正应力减小了33.0%,加固梁挠度增加了3.7‰,距离CFRP端部20 mm处截面上CFRP轴力减小了15.8%,RC梁弯矩增加了17.4%.

In order to investigate the mechanical behavior influence of the adhesive viscoelastic on reiforced concrete beams strengthened with the carbon fiber reinforced polymer, the Burger model was used to describe the stress- strain-time relation for the adhesive. The relaxation shear modulus with Prony series forms of Burger model was derived by the mathematical method of Laplace transform and inverse Laplace transform . The finite element software ABAQUS was used to simulate RC beams strengthened with the CFRP. The influence of the adhesive viscoelastic on the stresses of the adhesive, the axial force of the CFRP, the moment of RC beams and the deflection of the reinforced beam were analyzed. The results show that the adhesive viscoelastic affect the mechanical behavior of the reinforced beam to a certain degree. With the increasing of the loading time, the shear stresses and normal stresses peak value of the adhesive decrease, the axial force of the CFRP decrease, the bending moment of the RC beam increase and the deflection of the reinforced beam increase. When the adhesive layer thickness is 0. 2 mm, and the reinforced beam has been loaded for 30 d. The peak shear stress decreases by 40. 1%, the normal peak stress decreases by 33. 0 % , the deflection of the reinforced beam increase by 3.7 %On the cross section 20 mm away from the end of the CFRP, the CFRP axial force decreases by 15.8% and the bending moment of the RC beam increases by 17. 4% .