基于损伤的混凝土剪切应力—应变关系

Shear stress-strain relation of concrete based in the concept of damage

从微观层次上分析了混凝土试件在单调剪切荷载作用下的损伤破坏机制,解释了混凝土剪切本构关系的非线性和宏观特征;借助能量原理,建立了混凝土剪切本构方程模型;在混凝土的断裂应变服从对数分布假设的前提下,分析得出应力—应变关系仅与混凝土的峰值点割线剪切模量及原点切线剪切模量有关,该式能反映混凝土剪切试验上升段的几乎所有特点,与已有曲线相比较,结果吻合较好。

In this paper,the concrete materials damage which has been caused by monotonic shear loading is analyzed from mesoscopic fracture.The nonlinear performance of stress-strain curve of concrete is studied by using a class of mesoscopic springs model.With the help of the theory of energy,a stochastic damage constitutive law models of concrete under shear stress is established.Based on the hypothesis of logarithm normal distribution of the ultimate tensile strain.It is found that the stress-strain relationship can be uniquely determined by the ratio of scant shear modulus to tangent modulus.The relationship can also reflect all characteristics that shown in tests and has a good agreement with existed stress-strain curves.