Predictive System for Dynamic Fracture and Energy Absorption of Reinforced Concrete subjected to Three-Dimensional Confinement

本研究旨在建立混凝土的三维本构关系，并在此基础上建立钢筋混凝土结构延性和吸能能力的预测方法。编制了考虑应力-应变耦合和损伤/塑性条件的有限元分析程序。主要结论和研究成果如下：1.采用水平约束混凝土圆柱体和棱柱体进行了1.3维轴向反复受压试验。在此基础上，根据混凝土在应变场和应变场中的整体响应，推断了体积组分和偏位组分的塑性和断裂演化。阐明了三维约束效应在弹性剪切损伤和体积塑性剪切性损伤中的显着表现。根据混凝土三维全本构方程，建立了损伤复合材料的弹性、塑性和断裂相互作用的数学模型。在描述塑性演化和断裂时，研究人员明确采用弹性应变场作为主要指标。所建立的本构方程被安装在有限元分析程序中，该程序能够预测钢筋混凝土损伤连续体的塑性和断裂方面的结构能量消耗。本研究开发的系统可以对设置侧向限制剂的钢筋混凝土结构的吸能能力进行数值评估。通过验证分析，证明了该预测系统的通用性。

This research aims at developing 3-dimensional constitutive laws for concrete, on which a predictive method of structural ductility and energy absorption capacity of reinforced concrete is based. The finite element analysis program was advanced with consideration of coupled stress-strain field and damage/plasticity conditions. The followings are main conclusions and fruits of interest.1.3-dimensional loading test was conducted in use of laterally confined concrete cylinders and prisms externally subjected to axial cyclic conpression. Based on the results, plasticity and fracturing evolution of both volumetric and deviatoric components were deduced from the overall response of concrete in stress and strain fields. It was clarified that the 3-dimensional confinement effect significantly appears in shear damage of elasticity and volumetric plasticity named dilatancy.2. The interaction of elasticity, plasticity and fracturing of damaged composite was formulated in terms of 3-dimensional full constitutive equations of concrete. In describing evolution of plasticity and fracturing, the investigator explicitly adopted elastic strain field as a principal index.3. The above-developed constitutive equations were installed in finite element analysis program which enables to predict structurally consumed energy with regard to plasticity as well as fracturing of damaged continuum consisting of reinfored concrete. The path-dependency was especially focused.The system developed in this research makes it possible to get numerical evaluation for energy absorption capacity of reinforced concrete structures with lateral confinement agents. Through some verification analyzes, versatility of the predictive system was proved.