一种新的随动不均匀强(软)化砼本构模型

A New Kinematic Hardening and Softening Model for Concrete

通过对有关砼材料试验数据的认真分析 ,放弃了均匀强 (软 )化的传统假说 ,提出了一种由四种砼典型破坏试验数据标定材料加载面的实际形状和运动规律的新方法 .与只由一条轴压试验曲线标定的传统方法相比 ,该模型更加充分地利用了试验数据 .所建立的弹塑性随动强 (软 )化模型 ,不仅可以模拟混凝土材料的强化、软化和包氏效应 ,而且具有在考虑材料软化时无须将坐标系转到应变空间中的特点 .通过与试验结果的对比分析证明 ,正交法则可以很好地描述混凝土材料的塑性变形性能 ,所得到的刚度矩阵对称 ,能够节省大量的机时和计算费用 ,便于移植 .

On the basis of existing experimental results ,a new kinematic hardening and softening model was proposed for a plain concrete. The loading surface here is calibrated at six control points derived by four types of traditional material test. By abandon the conventional non associated flow rule, the new model can justify the validity and applicability of the associated flow rule and give a good prediction of the behavior not only in proportional loading in tension, shear, and compression test, but also in cyclic loading. Also, this proposed model can predict the softening behavior of concrete with no need to transfer the loading surface from stress space to strain space. The contrast to the test result shows the normal rules well descirbe the performance, and the derived stiffness matrix is symmetrical, so it can easily be transplanted and save much computer time and cost. Good agreement with a wide range of experimental data was observed.