The Study Of Random Damage Evolution Low Of Concrete Material Under Two-Axial Stress

The constitutive research of concrete material is one of the basic objects for concrete failure mechanics. Although the material has been widely used in the most of buildings, the constitutive relationship,which demonstrates the failure mechanism in the course of damage, is still unclear.Most of the constitutive equation based on elastic or plastic mechanic frame that have been proposed are deterministic, the random property of the concrete is seldom thought about.In this paper,based on the micro-mesom mechanics characters,and the reciprocity effect of different components and each component's mechanics character were taken account of .A types of new stochastic constitutive models which is base on different loading states such as two-axial tension-tension stress. This model can demonstrate the random damage evolution law of concrete material under such stress states. It can explain the random damage process of cancrete which demolished under two-axial stress,and the dispersione of stress .The view of the physics mechanic mechanism of different components which composed the concrete material,the internal grads tensile stress and the shear strength caused by compress stress under side compress stress has been study ,and the cause how the internal damage developed has also been analyzed.By extension of the uni-axial tensile stress and compression stress stochastic damage constitutive model,a types of new stochastic damage constitutive model was formed under consideration of the material failure that was caused by the grads tensile stress and the shear strength .Based on the assumption that the primary tensile stress is the main reason,caused concrete material fracture and the concept that the grads stress causes the internal stress redistribute,the two-axial tension-compression stochastic damage constitutive was deduced. The model can explain the weaken of the macro dynam phenomen of concrete and the process of damnification . Combining the fact of concrete damage can deduce the area of the utmost damage point by the similarity means of one-axial tension stress.