基于隐式梯度理论的混凝土细观随机断裂模型

摘要

Based on the basic concept of multiscale mechanics ,authors combined the gradient nonlocal theory with series-parallel spring model and developed a meso stochastic fracuture model for concrete . By introducing the fracture strain as a lognormal stochastic variable , uncontrollability of micro-fracture for concrete material was validated . Avoidance of layer sensitivity in traditional series-parallel spring model was achieved with nonlocalization theory . Moreover ,the authors analyzed the models from several aspects , such as the characteristic parameter ,evolution of local strain and damage ,as well as layer sensitivity .Finally ,the analysis based on the model were compared with experimental data , to verify the correctness of the model .The study results show that the model has a high efficiency ,and can be realized in computer software .%根据多尺度力学的基本思想，将隐式梯度非局部化理论与串并联弹簧模型理论相结合，建立了混凝土细观随机断裂模型。通过引入微弹簧断裂应变为服从对数正态分布的随机变量，验证了混凝土材料微观断裂的不可控制性；通过引入非局部化比例，解决了传统串并联弹簧模型的层数敏感性问题。对建立的模型从特征参数、局部应变与损伤的演化发展和层数敏感性几个方面进行了分析。最后，将模型结果与试验结果进行了对比，验证了该模型的正确性。研究结果表明：该模型计算效率高，且更加有利于在计算软件中实现。