碳纤维加固钢筋混凝土梁受弯性能非线性有限元分析

Nonlinear Finite Element Analysis on Flexural Performances of RC Beams Strengthened with CFRP Sheets

研究混凝土、受拉钢筋和CFRP在开裂、屈服、破坏各阶段的工作状态和受力特点,对认识CFRP加固机理和性能有着重要意义。应用ANSYS建立碳纤维加固钢筋混凝土梁有限元模型,利用单元生死技术模拟CFRP的不同工作状态,对试件梁开裂、屈服、破坏全过程进行非线性有限元分析。分析表明:在钢筋屈服后,CFRP加固钢筋混凝土梁在后期抗弯刚度、延性和极限承载能力方面均有增强;在结构承受较大初始荷载情况下,二次受力问题对加固梁的抗弯刚度、极限承载能力、延性存在一定影响;由于CFRP是在钢筋进入屈服阶段,应力停止增长后才发挥巨大作用,二次受力时的加固也能取得较好效果;分析结果与实测数据吻合。

In order to thoroughly comprehend the theory and performance of CFRP reinforcement, it is significant to study the different stress states of concrete, reinforcement bar and CFRP from cracking, yielding to destrorying. Here, the finite element models for flexural RC beams strengthened with CFRP sheets are created through ANSYS software, the different work ways of CFRP are simulated with element birth and death technology, and the nonlinear finite element analysis are made for the beams from cracking and yielding to destrorying. The results show that after yielding of the reinforcement bar, the late bending rigidity, ductility and ultimate beating capacity of the beams are all strengthened. When the initial load is big, the secondary load could influence the performances of CFRP reinforcement on all aspects as mentioned above. It is only on the yielding stage of the reinforcement bar that CFRP could produce its huge action of reinforcement, therefore, the reinforcement of secondary load can also be effective. The analytic results tally with the actual experiment data.