混凝土细观破裂过程的三维数值模拟及CT验证

3-D Numerical Simulation of Meso-Failure Process of Concrete and CT Experiment Verification

应用"被占领区域剔除"的思想,对原有的混凝土骨料三维随机分布的数值模型进行改进,提出了一种新的混凝土骨料三维随机分布数值模型建立的方法,并基于弹性损伤本构关系,采用双折线损伤演化模型描述混凝土细观各相弹性损伤退化,用弹性模量的折减程度来反映混凝土试件在加载过程中的损伤程度。对混凝土圆柱体试件进行了数值模拟计算,并依据混凝土破坏过程图比较了数值模拟的破坏过程与CT试验结果,发现试件破坏时裂纹的萌生、扩展过程与CT观测到的过程具有相似性,表明该模型较好地模拟了混凝土的不均匀性与各向异性,证明建立该模型的方法是可行的。

The ＂removal of the occupied region＂ method is used to improve the initial 3-D random distribution of concrete aggregate numerieal model, and the new 3-D random distribution of eonerete aggregate numerical model is established. The decrease of elastic line damage evolvement model based on elastic damage of concrete is described by conduplicatedamage constitutive relation; the damage degree of concrete specimen is reflected by the degree of decreasing of elastic-modulus. Then, 3-D numerical model of the cylinder specimen is calculated, the results of numerieal simulation and CT experiment is compared and analyzed in failure chart of concrete. It is found that when the testing propagation and expansion process are similar to the process observed by model can better simulate the inhomogeneity and anisotropism of concrete parts are damaged, the crack CT, thus, indicating that this so that the method of establishing the model is proved to be feasible, so the method of making model is feasible.