Abstract

A framework for investigating the mechanics of snow is proposed based on an advanced micro-scale approach. Varying strain rates, densities and temperatures are taken into account. Natural hazards i.e. snow avalanches are triggered by snow deforming at low rates, while a large group of industrial applications concerning driving safety or winter sport activities require an understanding of snow behaviour under high deformation rates. On the micro-scale, snow is considered to consist of ice grains joined by ice bonds to build a porous structure. Deformation and failure of bonds and the inter-granular collisions of ice grains determine the macroscopic response under mechanical load. Therefore, this study proposes an inter-granular bond and collision model for snow based on the discrete element method to describe interaction on a grain-scale. It aims at predicting the mechanical behaviour of ice particles under different strain rates using a unified approach. Thus, the proposed algorithm predicts the displacement of each individual grains due to inter-granular forces and torques that derive from bond deformation and grain collision. For this purpose, the inter-granular characteristics are approximated by an elastic viscous-plastic material law which is based on the temperature-dependent properties of poly-crystalline ice Ih.

Graphic abstract

中文翻译：

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用于建模雪的力学行为的离散元素框架—第一部分：力学行为和数值模型

摘要

基于一种先进的微尺度方法，提出了一个研究雪力学的框架。考虑了变化的应变速率，密度和温度。自然灾害（例如雪崩）是由低速变形引起的，而与驾驶安全或冬季运动有关的大量工业应用则需要了解高变形率下的雪况。在微观尺度上，雪被认为是由冰粒组成的，这些冰粒通过冰键结合在一起以形成多孔结构。键的变形和破坏以及冰粒的颗粒间碰撞决定了机械载荷下的宏观响应。因此，本研究提出了一种基于离散元方法的雪粒间键和碰撞模型，以描述颗粒尺度上的相互作用。它旨在使用统一的方法来预测不同应变率下冰粒的机械行为。因此，所提出的算法可预测由于键间变形和晶粒碰撞而产生的晶粒间作用力和扭矩所导致的每个晶粒的位移。为此目的，通过基于多晶冰Ih的温度相关特性的弹性粘塑性材料定律来近似颗粒间特性。

图形摘要