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摘要: 为了验证利用有限元法分析预应力混凝土梁极限承载能力的准确性, 对T形预应力混凝土模型梁进行了极限承载力加载破坏试验, 采用ANSYS有限元程序, 建立了T梁的分离式有限元模型, 分析了模型梁从加载到破坏全过程的受力和变形。发现利用实验与有限元法得到T梁的荷载-挠度曲线与荷载-应变曲线的变化趋势一致, 并呈现良好的非线性, 但是通过荷载试验得到T梁的超载能力为9.07 kN·m, 按照有限元分析得到的超载能力为12.48 kN·m, 偏差较大, 原因是分析模型偏于理想化。分析结果表明: 利用有限元法在总体上能够有效地模拟钢筋混凝土梁受力全过程中各个量的非线性变化, 对超载能力的求解是可行的。Abstract: In order to attested the analysis veracity of ultimate bearing capacity for prestressed concrete beam with finite element method, an loading experiment of ultimate bearing capacity was carried out, a detached finite element model of T beam was designed by using ANSYS finite element program, and the whole processes of T beam's stress and deformation from loading to destructing were analyzed.It is pointed that the variational trends of T beam's load-deflection curves and load-strain curves gained by experiment and the model are accordant, and the curves have good nonlinearity, but the experimental value of ultimate bearing capacity is 9.07 kN·m, the computational value is 12.48 kN·m, their error is appreciably big because of the idealization of the model.Analysis result shows that the nonlinear variations of all variables for prestressed reinforced concrete beam may are simulated by using finite element method in loading process as a whole, and the solution of ultimate bearing capacity is feasible.
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表 1 挠度、应力与应变计算值
Table 1. Calculation values of deflection, stress and strain
序号 荷载/kN 应变106ε 应力/MPa 挠度/mm 1 0.00 4 254.5 808.37 2.847 2 4.17 4 262.1 809.75 2.107 3 7.83 4 282.7 813.62 1.641 4 11.83 4 302.4 817.35 0.916 5 15.83 4 310.2 818.88 0.231 6 18.00 4 325.9 821.78 -0.154 7 22.00 4 349.8 826.34 -0.891 8 24.00 4 360.1 828.52 -1.259 9 25.33 4 380.3 832.22 -1.812 10 25.83 4 387.8 837.57 -1.899 11 26.83 4 397.5 838.63 -2.435 12 27.83 4 408.6 839.09 -2.778 13 29.83 4 427.3 843.91 -3.849 14 32.00 4 452.1 847.03 -5.157 15 33.00 4 463.5 851.93 -5.757 16 34.67 4 488.3 856.88 -6.678 17 37.67 4 541.8 862.80 -8.688 18 39.83 4 582.9 870.59 -10.317 19 42.00 4 652.6 883.85 -12.213 20 45.00 4 720.3 896.79 -15.615 表 2 试验数据
Table 2. Test data
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