钙质砂与结构接触面的本构模型研究

Constitutive Model of Calcareous Sand Structure Interface

基于接触面的宏、细观物理特征,建立了单调加载条件下钙质砂与结构接触面的弹塑性增量本构关系。从接触面的宏观条件上考虑,该模型将弹性模量取为法向压力的指数函数,采用非关联流动法则和Mohr-columb屈服函数,以及切向塑性功为硬化参量,适用于多数接触摩擦问题。在细观上将滑动面抽象为锯齿面,同时将摩擦系数取为塑性功的双曲线函数,以考虑钙质砂颗粒破碎对接触面力学特性的影响。模型概念简单、参数较少,通过理论计算与钙质砂拉拔试验结果比较,显示了模型的合理性。

Based on the macroscopic and microscopic features of contact, the incremental elastoplastic constitutive relation for the calcareous sand structure interface was developed under monotonic load. In the formulation of the model, through macroscopic conditions, the elastic modulus is an exponential function of normal stress, Mohr-Coulomb yield function, nonassociate flow rule and plastic tangential work-harderning were used, so it is applicable to a wide range of contact friction problems. Through microstructural consideration, the surface of slippage was idealized to be a saw-tooth asperity surface the friction coefficient was assumed to be a hyperbolic function of the plastic work in order to incorporate the effect of grain crushing on interface behaviors. The model is simpler on concept and requires few parameters, the experimental results are compared with the model prediction in pullout tests on calcareous sand-structure interface. It shows that the model is reasonable.