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为了深入研究折线配筋先张梁的力学性能,在优化选定的折点半径基础之上,以Ansys有限元分析软件为工具,采用分离式模型,建立了基于三维实体预应力筋单元的折线配筋先张梁非线性有限元分析模型,探讨了折点弯折角度、预应力筋布置间距、混凝土强度等级等结构、材料参数变化时先张梁折点局部应力状态与变化规律。研究结果表明:折点弯折角度对折点处σymax影响较小,但较大折角会使折点应力集中程度得到一定缓和;预应力筋间距虽然对折点处应力分布状态影响不大,但需要注意间距较小时在横向上可能产生的应力叠加现象;由于应力水平较低时不同强度等级混凝土的本构关系差别不大,对于预应力筋折点采用优化半径的先张梁,混凝土强度等级变化对折点处应力状态影响较小。
In order to further study the mechanical properties of pre-tensioned beams with polygons, the fracture line based on three-dimensional solid prestressing tendons was established by using the Ansys finite element analysis software as the tool and the separation model as the basis, Nonlinear finite element analysis model of prestressed beam of reinforcement was discussed. The structure of the fracture angle, prestressing tendon spacing and concrete strength grade were discussed. The local stress state and variation of pretensioned beam when material parameters changed were discussed. The results show that the bending angle of the bending point has a little effect on the σymax at the turning point, but the bending angle at the larger bending angle will moderate the stress concentration at the turning point. Although the spacing of the prestressing tendon has little effect on the stress distribution at the turning point, When the spacing is small, the stress superposition may occur in the horizontal direction. Because the constitutive relationship of concrete with different strength grades is not obvious when the stress level is low, Point stress state less affected.