Skip to main content
main-content
Top

About this book

This book systematically introduces readers to computational granular mechanics and its relative engineering applications. Part I describes the fundamentals, such as the generation of irregular particle shapes, contact models, macro-micro theory, DEM-FEM coupling, and solid-fluid coupling of granular materials. It also discusses the theory behind various numerical methods developed in recent years. Further, it provides the GPU-based parallel algorithm to guide the programming of DEM and examines commercial and open-source codes and software for the analysis of granular materials. Part II focuses on engineering applications, including the latest advances in sea-ice engineering, railway ballast dynamics, and lunar landers. It also presents a rational method of parameter calibration and thorough analyses of DEM simulations, which illustrate the capabilities of DEM. The computational mechanics method for granular materials can be applied widely in various engineering fields, such as rock and soil mechanics, ocean engineering and chemical process engineering.

Table of Contents

Frontmatter

Chapter 1. Introduction

Abstract
Generally, granular materials consist of a large number of irregularly-shaped particles and form complex granular systems together with surrounding fluid media and structures. Granular systems exhibit complex multi-scale and multi-medium mechanical properties.
Shunying Ji, Lu Liu

Fundamentals of Computational Granular Mechanics

Frontmatter

Chapter 2. Constructions of Irregular Shaped Particles in the DEM

Abstract
The discrete element method was first proposed by Cundall in the 1970s. It has been developed to be a powerful way of investigating behaviors of granular materials numerically.
Shunying Ji, Lu Liu

Chapter 3. Contact Force Models for Granular Materials

Abstract
In the discrete element method (DEM), each particle in the bulk material is considered to be an independent discrete element which has its own physical parameters (shape, density, size and et al.) and mechanical properties (elastic modulus, Poisson’s ratio and et al.). The interconnection and constraints between discrete particles are activated by contacts, which can fully reflect the discontinuity of granular materials. In DEM simulations, particles’ attributes, such as the position, velocity and angular velocity, are computed and stored at each time step. In sum, this method has the advantage of taking full account of the unique properties of each particle.
Shunying Ji, Lu Liu

Chapter 4. Macro-Meso Analysis of Stress and Strain Fields of Granular Materials

Abstract
Compared with typical continuous materials, granular materials have many unique discrete, nonlinear physical and mechanical properties. Originally, granular materials were generally treated as a continuum from a macroscopic perspective, and the mechanical behaviors were analyzed by the finite element method (FEM) or meshless method.
Shunying Ji, Lu Liu

Chapter 5. Coupled DEM-FEM Analysis of Granular Materials

Abstract
The finite element method (FEM) is mature in theory. It has the advantage of being suitable for solving continuum problems with the characteristics of accurate and reliable numerical results and high efficiency when modelling small deformation problems.
Shunying Ji, Lu Liu

Chapter 6. Fluid-Solid Coupling Analysis of Granular Materials

Abstract
The coupling between granular materials and fluid widely exist in nature and human activities, such as sediment in the river course, seepage of liquid water in sand and gravel soil, and interactive movement in the gas-solid two-phase flow in chemical equipment. In order to study the fluid-solid coupling problem of granular materials, the discrete element method (DEM) is usually adopted to simulate solid particles, while various computational methods can be used to simulate fluid.
Shunying Ji, Lu Liu

Chapter 7. High Performance Algorithm and Computing Analysis Software of DEM Based on GPU Parallel Algorithm

Abstract
Taking the DEM as the main approach, computational granular mechanics has been widely applied in geotechnical engineering, chemical process, geological disaster, mining engineering, marine engineering, agricultural engineering, mechanical engineering, atmospheric science, medical pharmacy, life science and other fields, and obtained many important research results. With the increasing particle types and combination with traditional numerical methods such as computational solid mechanics and computational fluid dynamics, the DEM has been gradually extended to the material damage and fracture, fluid-structure interaction and other fields. Meanwhile, it also provides a powerful approach to solve the granular mechanics problems in the natural ecology, industrial engineering and life sciences. With the development of computational mechanics of granular materials, the corresponding simulation software have been gradually developed and applied to different engineering fields, which have become an effective means to solve the granular materials problems.
Shunying Ji, Lu Liu

Engineering Applications of Computational Granular Mechanics

Frontmatter

Chapter 8. DEM Analysis of Ice Loads on Offshore Structures and Ship Hull

Abstract
With the development of offshore oil and gas industry in the cold region, the ice load and ice failure modes during the interaction between sea ice and offshore platform structures in cold regions play important roles in the structural design and fatigue vibration analysis of offshore platforms.
Shunying Ji, Lu Liu

Chapter 9. DEM Analysis of Mechanical Behaviors of Railway Ballast

Abstract
The ballasted railway track, as one of the most important ways of transportation, has a wide distribution in China. The main functions of the railway structure are to withstand and transfer the load from the sleeper, to maintain the stability of the track geometry, and to mitigate and absorb the impact and vibration from the wheel-rail interaction. As a kind of typical granular materials, railway ballast exhibits strong nonlinear properties such as non-uniformity, discontinuity and anisotropy.
Shunying Ji, Lu Liu

Chapter 10. DEM Analysis of Vibration Reduction and Buffering Capacity of Granular Materials

Abstract
Granular materials is a complex system, and the energy of the system is mainly dissipated through inelastic collisions and sliding friction between particles (Royer et al. 2007; Ramírez et al. 1999). Under the external load, strong compression and collision between particles have been observed.
Shunying Ji, Lu Liu
Additional information

Premium Partner

    Image Credits