混凝土非线弹性正交异性本构模型

Nonlinear elastic orthotropic constitutive model for concrete

通过对混凝土多轴应力下强度、变形和破坏形态的大量试验研究，建立了非线弹性正交异性本构模型。根据试验规律，建议了拉应力指标α以划分混凝土的破坏形态，并分别给定适宜的等效单轴应力—应变关系；定义了合理的应力水平指标β；给定拉、压应力状态泊松比值的不同变化规律和公式。本构模型与试验曲线比较，无论是应力—应变曲线的形状和绝对值。

A nonlinear elastic orthotropic constitutive model is proposed based on experimental investigation on strength, deformation and failure mode of concrete under multiaxial stress states. Tensile stress parameter α is defined to classify failure modes and establish appropriate equivalent uniaxial stress strain relationships. Poisson's ratio is formulated in accordance with different behavior under tension and compression. Furthermore, stress level parameter β is given with consideration of experimental and practical loading condition as well as computational simplicity. The proposed constitutive model provides good agreement between experimental and analytical stress strain curves.