预应力CFRP布加固损伤RC梁的动力特性研究

Study on dynamic characteristics of damaged RC beam strengthened by prestressed CFRP sheets

从理论上推导了预张力与损伤RC梁固有频率之间的定量关系。同时进行了预应力CFRP布加固RC梁的动力特性试验,测定不同预张力条件下,完好梁与损伤梁的一阶频率值。而后利用ANSYS软件建立钢筋混凝土完好梁的有限元模型,根据损伤梁的动力测试结果,运用优化分析的方法得到损伤梁混凝土刚度折减系数;利用一阶频率的试验值对公式进行线性拟合,得到频率影响因素及损伤梁频率计算公式。最后将加固损伤梁一阶频率的理论值与试验值进行比较,发现在低预应力作用下,理论计算结果基本能反映出试验值随预张力变化的趋势,试验值与理论值吻合较好。

The dynamic characteristics of RC damaged beams strengthened by prestressed CFRP sheets were studied theoretically and the relation between eigen frequency and pretension was derived.Moreover,the dynamic characteristics were also tested with the primary eigen frequency measured under different pretensions.The finite element model of concrete beam in good condition was set up by use of ANSYS software,and the reduction factor of elastic modulus of concrete was obtained taking advantage of the optimization tool of ANSYS based on the test data of damaged beam.According to the value of primary eigen frequency of beam strengthened by prestressed CFRP sheets in good condion,a linear fit to the formula of calculating the frequency was carried out and the frequency factor as well as the formula for calculating primary eigen frequency of damaged beam were put forward.The theoretical value of primary eigen frequency was compared with the experimental values.At low prestress,the theoretical calculation results reflect the trend of experimental data;both results are in good agreement.