The material point method (MPM) has been increasingly used to simulate coupled hydro-mechanical problems involving large deformations. However, when addressing saturated porous media with an almost incompressible liquid phase, the classic explicit MPM with low-order interpolation functions is not stable if no further stabilization approach is used. In this study, a solid-velocity–liquid-velocity-based

A simple and robust C++ code for the material point method (MPM) called Karamelo is presented here. It was designed to provide an open source, fast, light and easy-to-modify framework for both conducting research on the MPM and research using the MPM, instead of a finite element package. This paper presents the overall philosophy, the main design choices and some of the original algorithms implemented

The FOSS CFD-SPH code SPHERA v.9.0.0 (RSE SpA) is improved to deal with “fluid–solid body” interactions under no-slip conditions and laminar regimes for the simulation of hydrodynamic lubrication. The code is herein validated in relation to a uniform slider bearing (i.e. for a constant lubricant film depth) and a linear slider bearing (i.e. for a film depth with a linear profile variation along the

Masonry arches are usually composed of individual blocks or voussoirs, which are highly discontinuous and nonlinear, and it is extremely difficult or even impossible to simulate their collapse behavior using finite element methods. Therefore, a combined finite–discrete element method (FDEM) is employed to simulate the collapse behavior of dry-joint masonry arches induced by spreading supports. With

Discrete element modeling (DEM) of polydisperse granular materials is significantly more computationally expensive than modeling of monodisperse materials as a larger number of particles are required to obtain a representative elementary volume, and standard contact detection algorithms become progressively less efficient with polydispersity. This paper presents modified contact detection and inter-processor

This paper presents a brief review of grand challenges of Smoothed Particle Hydrodynamics (SPH) method. As a meshless method, SPH can simulate a large range of applications from astrophysics to free-surface flows, to complex mixing problems in industry and has had notable successes. As a young computational method, the SPH method still requires development to address important elements which prevent

The discrete element method (DEM) is a general discrete modeling technique traditionally used to model granular material and discontinuous phenomena such as fracture and fragmentation of solids. We investigate the efficacy of DEM to model deformable elastic continua, cantilever beams in particular, and describe their mechanical behavior under loading. Of distinct interest is the ability of DEM to capture

Particle dampers show a huge potential to reduce undesired vibrations in technical applications even under harsh environmental conditions. However, their energy dissipation depends on many effects on the micro- and macroscopic scale, which are not fully understood yet. This paper aims toward the development of design rules for particle dampers by looking at both scales. This shall shorten the design

A fundamental numerical model at the powder particle scale based on the material point method (MPM) is developed for selective laser sintering (SLS). In order to describe the thermo-mechanical phenomena, a laser heat source model with a Gaussian energy distribution and the Perzyna viscoplastic model with a return mapping algorithm are employed. The principal process conditions, such as the laser power

This paper focuses on the numerical analysis of a discrete version of a nonlinear reaction–diffusion system consisting of an ordinary equation coupled to a quasilinear parabolic PDE with a chemotactic term. The parabolic equation of the system describes the behavior of a biological species, while the ordinary equation defines the concentration of a chemical substance. The system also includes a logistic-like

Contact conduction heat transfer behavior in a rotary drum using the discrete element method (DEM)-based simulation codes MFIX-DEM (open-source) and EDEM (commercial) is investigated. Simulations are performed to compare the performance of open-source and commercial code models with experimental data. This study also aims to investigate the effects of particle size distribution (PSD), rotation speed

We study the erosion dynamics of wet particle agglomerates inside a simple shear flow of noncohesive granular materials by relying on the three-dimensional discrete-element simulations. The simulation model is discretized by assembling of wet and dry spherical particles. By systematically varying different parameters related to the shear flow of dry particles (the shear rate), the wet agglomerates

Natural granular materials such as sands often possess complex microstructural features including cleavage and minerals interfaces. Those features bring apparent mechanical anisotropy to particles and are known to have pronounced influence on particle crushing characteristics. This paper presents a multiscale simulation of continuous crushing of granular sand under one-dimensional compression in consideration

The presence and generation of fines and dust in the bulk of biomass pellets have inflicted several problems in the supply chain during transportation and storage, and the breakage behavior of pellets has been scarcely studied so far. Fines and dust are the consequences of impact and abrasive forces through the whole supply chain; however, the breakage happens at the particle level. Therefore, to study

Experimental and field investigations for solution mining processes have improved intensely in recent years. Due to today’s computing capacities, three-dimensional simulations of potential salt solution caverns can further enhance the understanding of these processes. They serve as a “virtual prototype” of a projected site and support planning in reasonable time. In this contribution, we present a

This paper is devoted to an unresolved model for the simulation of air invasion in immersed granular flows without interface reconstruction between the liquid and the gas. Experiments of air invading a granular bed immersed in ethanol were achieved in a Hele-Shaw cell to observe the gas invasion paths and to calibrate the numerical multiscale model. The grains movements are computed at a fine scale

In this work, two modifications of an adaptive particle method based on the moments of the internal concentration of numerical particles are presented to introduce the effect of local shears on the mass transport in natural flows. This moment method uses a Taylor expansion of the flow velocity field to derive the transport equation of moments. The first modification is based on the introduction of

Nearly thirty years since its inception, the combined finite-discrete element method (FDEM) has made remarkable strides in becoming a mainstream analysis tool within the field of Computational Mechanics. FDEM was developed to effectively “bridge the gap” between two disparate Computational Mechanics approaches known as the finite and discrete element methods. At Los Alamos National Laboratory (LANL)

We present an explicit incompressible smoothed particle hydrodynamics formulation with stabilized pressure distribution and its implementation in a multiple graphics processing unit environment. The pressure Poisson equation is stabilized via both pressure invariance and divergence-free conditions, and its explicit formulation is derived using the first step of the Jacobi iterative solver. Also, we

In the work at hand, two methods for the calibration of the elastic material parameters of bonded-particle models (BPMs) are proposed. These methods are based on concepts of classical mechanics and enable a faster calibration compared to the conventional trial and error strategy. Moreover, they can be used to counter-check the consistency of the BPM. In the first method, the mathematical model is linearized

This paper introduces a three-dimensional (3D) simulation to model the elasto-plastic deformation of ductile materials by discrete element method (DEM) using cohesive plastic beam approach. The Euler–Bernoulli beam theory is applied to calculate force and torque reactions of the cohesive beam bond that can account for plastic strain. In order to simulate the elasto-plastic behavior of materials, a

This work presents a fully Lagrangian Finite Element Method (FEM) with nodal integration for the simulation of fluid–structure interaction (FSI) problems. The Particle Finite Element Method (PFEM) is used to solve the incompressible fluids and to track their evolving free surface, while the solid bodies are modeled with the standard FEM. The coupled problem is solved through a monolithic approach to

Physics engines, originally developed to simulate physical and mechanical processes in modern video games, are increasingly used as a scientific computational platform in many disciplines due to their high computational efficiency. This study explores the feasibility of using an open-source physics engine, Project Chrono, to simulate direct shear tests. This study develops a series of pre-processing

A novel immersed boundary lattice Boltzmann method (IB-LBM) is proposed to simulate the complex thermal particle flows. In the present scheme, the boundary condition is directly implemented by correcting the distribution function at the neighboring points around the interface, similar to the original LBM. Furthermore, an adjustment parameter is introduced for ensuring the accuracy in the boundary treatment

A general framework for developing nonlinear hyperelastic/plastic constitutive laws for anisotropic solids experiencing large strains and strain rates has been developed. The proposed framework does not rely on the “a priori” known strain energy function, but instead introduces a physical decomposition of the material element into seven physically independent stress bearing mechanisms, each of which

This study presents a numerical investigation on the fracture mechanism of tension stiffening phenomenon in reinforced concrete members. A novel approach using the discrete element method (DEM) is proposed, where three-dimensional randomly generated distinct polyhedral blocks are used, representing concrete and one-dimensional truss elements are utilized, representing steel reinforcements. Thus, an

As the earliest meshless method, smoothed particle hydrodynamics (SPH) has been applied in solid dynamics because of its great potentials in simulating extremely large deformations. In terms of the essence of SPH, it uses a kernel function for numerical approximations. Some studies demonstrate mathematically that the types of the kernel function directly influence the stability and overall accuracy

Within this paper, the modelling and simulation of extrusion-based Additive Manufacturing (AM) processes of curing polymers is presented. The challenge of the AM is the adjustment of processing parameters. This includes the application of laser radiation to locally accelerate the curing in order to control the final geometry of the implant. Since complex multi-physical coupling effects are hardly predictable

It has been shown experimentally that under mixed tensile and compressive stress states, a corresponding mixed-mode fracture will occur. In this paper, the formation of mixed-mode fractures is investigated using the combined finite–discrete element method. A series of simulations with confining pressures ranging from 7.5 to 150 MPa generate a spectrum of mixed-mode failure conditions. These stress

This work presents a computational method for the solution of problems involving flowing fluid media laden with solid particles. The idea is based on previous works by the authors on (though then separately considered) fluid–structure interaction and particle dynamics. The fluid problem is treated through an Eulerian finite element approach, with the resulting system of nonlinear equations being iteratively

In this paper, it is argued that science of discontinua represents a major paradigm shift in how scientific research is done. First, a historical perspective is given, followed by key aspects of discontinuum simulations and its potential in aiding research and development. This is followed by a philosophical perspective on equivalence of matter and information as inspired by Aristotle’s quest for souls

When a dynamic earthquake rupture propagates on a fault in the Earth’s crust, the medium around the fault is dynamically damaged due to stress concentrations around the rupture tip. Recent field observations, laboratory experiments and canonical numerical models show the coseismic off-fault damage is essential to describe the coseismic off-fault deformation, rupture dynamics, radiation and overall

Uniqueness of solutions to the SPH integral formulation of the hydrostatic problem, and the convergence of such solution to the exact linear pressure field, are theoretically demonstrated in this paper using Fourier analytical techniques. This problem involves the truncation of the kernel when the Dirichlet boundary condition (BC) on the pressure is imposed at the free surface. Certain hypotheses are

By using nonlocal discrete force functions, peridynamics (PD) can effectively deal with the problems involving discontinuities and singularities. As a continuum-based particle method, the material point method (MPM) and its advanced version, generalized interpolation material point method (GIMP), use local and nonlocal spatial discretization, respectively, to effectively simulate large deformations

The symbol was introduced incorrectly inside the “Time-stepping the solution” box, directly under the “Compute first Piola–Kirchhoff stress tensor Pi” as in “Appendix A” listing.

Underwater structures can be seriously damaged by a metal jet associated with underwater explosion. Three main modes—Shaped Charge Jet, Jetting Projectile Charge and Explosive Formed Projectile—are included for traditional metal jets. Compared with the traditional ones, an annular jet may cause more serious damage into a target. Hence, a comparison for the entire process of annular and general jets

In ice-covered regions, the upward–downward ice-breaking cones are applied widely to reduce the ice load on the vertical jacket offshore platforms. The ice load is affected by the diameter of cone at the water level. In particular, the sea ice can impact on the vertical portion of the platform which is beyond the covered area of the upward–downward cone under the extreme low or high water level. In

The stable discharge of particles through the hopper plays a key role in many industrial applications. In order to investigate the discharge characteristics of binary particles in a rectangular hopper with an inclined bottom, the discrete element method (DEM) was used to simulate the discharge process. The accuracy of DEM was validated by comparing calculated and experimental values. The influences

The Material Point Method (MPM) is a numerical technique that combines a fixed Eulerian background grid and Lagrangian point masses to simulate materials which undergo large deformations. Within the original MPM, discontinuous gradients of the piecewise-linear basis functions lead to the so-called grid-crossing errors when particles cross element boundaries. Previous research has shown that B-spline

The discrete element method (DEM) is a powerful tool for simulating complex mechanical behaviors which discretizes the targeted medium with particles. The properties of particle assemblies used in DEM simulations directly impact the behavior of the simulated medium. It is thus of critical importance to generate particle assemblies so as to (1) avoid any bias induced by their fabric and (2) conform

Fine and cohesive powders typically exhibit low packing density, with solid volume fraction around 0.3. Discrete element modelling (DEM) of particulate materials and processes typically employs spherical particles which have much larger solid fractions (e.g. 0.64 for dense random packing of frictionless spheres). In this work a range of quasi-spherical particles are designed, represented by a number

In this work, we present a newly developed workflow to study the combined effect of shear and normal stresses upon a preexisting fracture plane. This workflow is used to study the behavior of both single grain and polycrystalline materials, with varying material properties. The surface roughness and aperture of preexisting fractures are highly dependent upon the dynamic stress behavior within rock

From its inception, the combined finite discrete element method has used a distributed potential contact force algorithm to resolve interaction between finite elements. The contact interaction algorithm relies on evaluation of the contact force potential field. The problem with existing algorithms is that the potential field introduces artificial numerical non-smoothness in the contact force. This

Three-dimensional imaging techniques, such as X-ray computed tomography, have been used to scan realistic particle geometries. However, these techniques are labor intensive, time-consuming, and costly to obtain a large number of particles. Therefore, it is desirable if computers can be taught to generate realistic particles based on given morphological properties. This paper develops a particle generation

Simulations of multi-body dynamics for computer graphics, 3D game engines, or engineering simulations often involve contact and articulated connections to produce plausible results. Multi-body dynamics simulations generally require accurate contact detection and induce high computational costs because of tiny time increments. As higher accuracy and robustness are continually being sought for engineering

Theoretical analysis and nowadays advanced numerical simulations for bedload particle transport widely share a popular assumption: All sediments are spherical and can be simplified as spheres, which apparently differs from reality. In order to explore the shape effects of sediment particles on their transport and to find out the possible consequence originated from the spherical assumption, a particle

This paper presents a new three-dimensional thermo-mechanical (TM) coupling approach for thermal fracturing of rocks in the finite–discrete element method (FDEM). The linear thermal expansion formula is implemented in the context of FDEM according to the concept of the multiplicative split of the deformation gradient. The presented TM formulation is derived in the geo-mechanical solver, enabling thermal

This paper presents a new approach for the modelling of heat transfer in 3D discrete particle systems. Using a combined finite–discrete element (FDEM) method, the surface of contact is numerically computed when two discrete meshes of two solids experience a small overlap. Incoming heat flux and heat conduction inside and between solid bodies are linked. In traditional FEM (finite element method) or

Transient dynamics of fracturing media has received significant attention in recent years, and a number of simulation approaches have been developed. One of these is the combined finite-discrete element method (FDEM). FDEM produces complex fracture and fragmentation patterns in processes such as blast loads, blasting, impact, mining, and oil exploration. To address a wide range of multi-physics problems

In this paper, uniaxial compression tests on layered rock specimens are numerically modelled using the discrete element method to investigate the effect of a soft interlayer on the strength and deformation of rock specimens. For these simulations, the thickness and dip angle of the soft interlayer were varied. Thirty-five numerical models for different cases were established after calibrating the micro-mechanical

The land topography of certain mountainous regions can be highly variable. The geometry of the topography may be influenced by geological, seismic, weathering, and other processes. The creation of the full 3D numerical models of these topographies represents a challenge. In this work, we present a methodology that allows to create numerical material point method (MPM) models based on the contour lines

The application of the combined finite-discrete element method (FDEM) to simulate fracture propagation in fibre-reinforced-concrete (FRC)-lined tunnels has been investigated. This constitutes the first attempt of using FDEM for the simulation of fracture in FRC structures. The mathematical implementations of the new FDEM joint-element constitutive model are first introduced, and the numerical model

A fluid–structure interaction (FSI) methodology is presented for simulating elastic bodies embedded and/or encapsulating viscous incompressible fluid. The fluid solver is based on finite volume and the large eddy simulation approach to account for turbulent flow. The structural dynamic solver is based on the combined finite element method–discrete element method (FEM-DEM). The two solvers are tied

Smoothed particle hydrodynamics (SPH) has become a popular numerical framework of choice for simulating free-surface flows, mainly for Newtonian fluids. The topic regarding the simulation of non-Newtonian free-surface flows, however, remains relatively untouched due to difficulties regarding the computation of viscous forces. In previous approaches, the viscous forces acting on each SPH particle were

This paper presents an enhanced coupled approach between the finite element method (FEM) and the discrete element method (DEM) in which an adaptive remeshing technique has been implemented. The remeshing technique is based on the computation of the Hessian of a selected nodal variable, i.e. the mesh is refined where the curvature of the variable field is greater. Once the Hessian is known, a metric

The paper analyzes the contribution of the sub-particle-scale large-eddy simulation (SPS-LES) turbulent model on the dynamic behavior of the weakly compressible moving-particle semi-implicit (WCMPS) method. To search a robust WCMPS method configuration, the next models are tested: two pressure gradient models, two Laplacian models and the constrained stabilization technique through the control adjustment

In selective laser melting (SLM), three-dimensional parts are build up from a metal powder bed by layer-wise melting with a laser. While SLM offers a high flexibility in geometrical design and material texture, the interplay of dozens of parameters is difficult to analyze experimentally. The current research focuses on numerical simulation to increase confidence in manufactured parts and to reduce

In many granular material simulation applications, DEM capability is focused on the dynamic solid particulate flow properties and on systems in which millions of particles are involved. The time of relevance is many seconds or even minutes of real time. Simplifying assumptions are made to achieve run completion in practical timescales. There are certain applications, typically involving manufactured

In this study, the combined finite–discrete element method (FDEM), which merges the finite element-based analysis of continua with discrete element-based transient dynamics, contact detection, and contact interaction solutions, is used to simulate the response of a flyer plate impact experiment in a Westerly granite sample that contains a randomized set of cracks. FDEM has demonstrated to be a strongly

In the interaction between rubber tire and granular terrain, the dynamic behavior of granular terrain is significantly affected not only by the shape of soil grains, but also by the deformation contact of tread rubber. Therefore, the effect of these two factors should be considered in tire–sand interactions. In this study, an improved contact model including the effect of sand grain shape and tread