混凝土弹塑性损伤本构模型研究Ⅱ:数值计算和试验验证

针对建议的基于能量的混凝土弹塑性损伤本构模型[1],将损伤演化和塑性变形解耦,本文建立了模型的弹性预测-塑性修正-损伤修正数值分析框架,给出了无条件稳定的应力更新算法和相应的算法一致性切线模量。在弹性预测-塑性修正过程中,利用谱分解回映算法建立了塑性流动因子和硬化参数的统一迭代格式,减小了有效应力更新的计算量。根据上述数值算法,编制非线性有限元分析程序,对单调和低周反复荷载作用下的混凝土材料和结构试验进行数值模拟,分析结果表明建议的弹塑性损伤本构模型可以较好地描述混凝土材料的典型非线性行为,其数值方法是有效的,为进一步的结构非线性分析应用奠定了基础。

ELASTOPLASTIC DAMAGE CONSTITUTIVE MODEL FOR CONCRETE BASED ON DAMAGE ENERGY RELEASE RATES ,PART Ⅱ :NUMERICAL ALGORITHM AND VERIFICATIONS

With regard to the energy-based elastoplastic damage model presented in the previous paper~([1]),by decoupling plastic strains and damage evolutions,the three-step numerical framework,i.e.,elastic predictor-plastic corrector-damage (corrector),and the algorithm for updating the stress and the corresponding algorithm consistent tangent modulus,are provided in this paper.In the procedure of updating the effective stress,the unified Newton-Raphson iterative formulation of the plastic consistent parameter and the hardening parameters is established by using spectral decomposition in the effective stresses space.In accordance with the above algorithm,a nonlinear finite element analysis program is developed,and tests of concrete under monotonic and cyclic loadings are simulated.The predictive results show that the suggested model and corresponding algorithm can describe the typical nonlinear behaviors of concrete materials.