多轴应力状态下混凝土的动态强度准则

A dynamic strength criterion of concrete under multiaxial stress state

为了解复杂应力状态下混凝土动态强度变化规律,提出了一个考虑应变率效应的八面体应力空间的多轴静动破坏准则.该准则的空间破坏包络曲面采用二次函数形式,在偏平面上的破坏包络线采用Willam-Warnke模型在偏平面上的椭圆曲线,使用特征应力点法对拉压子午线方程进行修正以考虑偏平面上罗德角对动态强度的影响.通过对大量混凝土多轴静动强度试验成果的分析,表明此强度准则与已有的试验结果吻合较好,能很好地反映平面应力或三轴应力状态下普通混凝土的静动强度变化规律,并且形式简单,便于实际应用.

In order to understand the dynamic strength properties of the concrete under complex stress state, a united multiaxial static-dynamic strength criterion is established in the octahedral stress space in which the strain rate effect is considered. The failure surface of the proposed model in three-dimensional （3D） stresses space is represented by a quadratic function. The strength envelope in the deviatoric plane is described by an elliptic curve similar to that of Willam-Warnke model, and the tensile and compressive meridians are calibrated using typical stress points method to consider the effect of the Lode angle on the dynamic strength. By the analysis of multiaxial static and dynamic strength test data of concrete, it is proved that the predicted strength of the failure criterion is in good agreement with the experimental data. Meanwhile, the strength criterion has simple expression form and is convenient for practical application.