混凝土正交各向异性损伤模型的研究

Study on an Orthotropic Damage Model for Concrete

混凝土的基本破坏机理是微开裂。基于不可逆过程热力学，用连续介质力学的方法建立了一个混凝土正交各向异性损伤模型。在模型中用一个二阶对称张量Ｄ来描述损伤，利用能量等效假设来考虑损伤对弹性张量的影响，并直接假设了损伤增量与不可逆应变增量之间的关系式，而不是用经典塑性理论来处理不可逆应变。模型只需一个加载函数。模型与Ｋｕｐｆｅｒ，Ｔａｓｕｊｉ等的试验结果吻合较好。

Microcrack is the failure mechanism of concrete.In this paper,an orthotropic damage model for concrete is developed within the general framework of continuum thermodynamics for irreversible process with internal variables.Damage induced material anisotropy is characterized by a symmetric second order tensor D.Hypothesis of energy equivalence is used to account for the changes of the elastic tensors induced by damage.The relationship between the irreversible strain increments and the damage increments is proposed directly.There is only one loading function in the model.Comparisons between the model and experimental results of Kupfer and of Tasuji agree well.