考虑粘结滑移的平面组合式单元模型研究与应用

RESEARCH AND APPLICATIONS OF A PLANE EMBEDDED COMBINED ELEMENT MODEL CONSIDERING BOND AND SLIP

配有弯起钢筋的简支梁算例证明,在钢筋混凝土有限元计算中为得到合理的裂缝分布与裂缝宽度,需顺裂缝走向划分网格。当配筋复杂时,采用分离式单元模型计算裂缝分布是困难的。结合现有分离式和组合式钢筋混凝土有限单元模型的优点,推求了一种新的组合式单元模型。该模型既能模拟钢筋与混凝土之间的粘结滑移,较正确地得到裂缝分布与裂缝宽度,又能使混凝土网格划分不受钢筋位置的影响。拉拔构件、配有弯起钢筋简支梁和水电站蜗壳等算例表明,该模型网格划分方便、计算精度高,可用于工程设计。

It was observed, from a simple concrete beam with bent-up reinforcements, that the mesh should be divided along cracking direction to get reasonable distribution and width of crack in RC FEM （Reinforced Concrete Finite Element method） and also that it would be difficult to calculate with discrete elements when the distribution of reinforcements is complicated. Thusly, a new embedded combined element is developed, which can not only simulate the bond and slip between reinforcement and concrete, then get a relatively correct crack distribution and width, but also generate mesh freely, not influenced by the position of reinforcements. The numerical simulations of pull-out test, simply supported beam with bent-up reinforcement and the volute in water power station show that this model can generate the mesh conveniently and get high precision. It can be applied in project design.