混凝土材料的粘塑性损伤统一本构模型

UNIFIED CONSTITUTIVE MODEL FOR VISCOPLASTIC DAMAGE OF CONCRETE MATERIALS

发展了只适用于金属类材料的粘塑性统一本构理论,借助经典塑性理论的基本法则,建立了无屈服面和无破坏面的混凝土材料的粘塑性损伤统一本构模型。放弃了传统统一本构模型的静水压不影响非弹性变形和无非弹性体积膨胀的基本假设;发展了间断的经典塑性乘子,使其为连续函数,并提出了相应的构造方法,拓展定义了其物理意义。数值模拟显示,此本构模型能够模拟混凝土材料的率相关性质、在压缩载荷作用下的体积膨胀现象和由损伤引起的应力软化和刚度退化现象。

By mean of the basic principle of classical plasticity theory, a new constitutive model for concrete is proposed, which do not comprises formal hypotheses of a yield surface and a failure criteria. Moreover, the typical unified viscoplastic constitutive model only used to analyze the metal materials is developed as well. The two hypotheses of typical unified viscoplastic constitutive theory is given up that the accumulated inelastic strain does not produce a significant change in the volume and the accumulated inelastic strain and strain rate appear to be independent of hydrostatic stress. The physical meaning of plastic multiplier is extended. Simultaneously, its expression of continuous function is given. The results from numerical simulation show that this model is capable of reproducing the significant deformation phenomena, including strain-rate sensitivity, volume dilatancy under compression, and stiffness degradation and strain-softening behavior beyond the peak stress induced by damages and fractures.