A visco‐elasto‐plastic model for granular materials under simple shear conditions
A visco‐elasto‐plastic model for granular materials under simple shear conditions
复制标题
简单剪切条件下颗粒材料的粘弹塑性模型
DOI：
10.1002/nag.2391
复制
发表时间：
2016
影响因子：
4
通讯作者：
D. Vescovi
中科院分区：
文献类型：
--
作者：
I. Redaelli;C. Prisco;D. Vescovi
快速滑坡的数值模拟是相当复杂的，主要是因为能够模拟颗粒材料在崩塌前和崩塌后状态下的力学行为的本构模型仍然缺失。本文的目标是引入一种本构模型，能够捕获从准静态到动态条件下的干颗粒流的响应，特别是当材料经历一种固体到流体的相变。考虑了在简单剪切条件下全同球体的理想组合。在本构模型中，孔隙比和颗粒温度被选为状态变量，剪切应力和正应力都被计算为两个贡献的总和：准静态贡献和碰撞贡献。前者是通过使用包含临界状态概念的理想弹塑性模型确定的，而后者是从颗粒气体的动力学理论导出的。颗粒温度的演变，从根本上控制材料的相变，是通过施加的动能波动能量平衡。在定压和定容两种情况下对本构关系进行了积分，并研究了剪切应变率、初始孔隙比和法向压力对力学响应的影响。版权所有© 2015约翰威利父子有限公司.
The numerical simulation of rapid landslides is quite complex mainly because constitutive models capable of simulating the mechanical behaviour of granular materials in the pre‐collapse and post‐collapse regimes are still missing. The goal of this paper is to introduce a constitutive model capable of capturing the response of dry granular flows from quasi‐static to dynamic conditions, in particular when the material experiences a sort of solid‐to‐fluid phase transition. An ideal assembly of identical spheres under simple shear conditions is considered. In the constitutive model, void ratio and granular temperature have been chosen as state variables, and both shear and normal stresses are computed as the sum of two contributions: the quasi‐static one and the collisional one. The former is determined by using a perfect elasto‐plastic model including the critical state concept, while the latter is derived from the kinetic theory of granular gases. The evolution of the granular temperature, fundamentally governing the material phase transition, is obtained by imposing the kinetic fluctuating energy balance. The constitutive relationship has been integrated, under both constant pressure and constant volume conditions, and the influence of shear strain rate, initial void ratio and normal pressure on the mechanical response has been investigated. Copyright © 2015 John Wiley & Sons, Ltd.