scholarly journals A modified bond model for describing isotropic linear elastic material behaviour with the discrete element method

2021 ◽  
Author(s):  
Rahav Gowtham Venkateswaran ◽  
Ursula Kowalsky ◽  
Dieter Dinkler
Keyword(s):  
Discrete Element Method ◽  
Elastic Material ◽  
Poisson’S Ratio ◽  
Strain Energy ◽  
Discrete Element ◽  
Poisson's Ratio ◽  
Linear Elastic Material ◽  
Linear Elastic ◽  
Bond Model ◽  
Element Method

AbstractRecently, the discrete element method is increasingly being used for describing the behaviour of isotropic linear elastic materials. However, the common bond models employed to describe the interaction between particles restrict the range of Poisson’s ratio that can be represented. In this paper, to overcome the restriction, a modified bond model that includes the coupling of shear strain energy of neighbouring bonds is proposed. The coupling is described by a multi-bond term that enables the model to distinguish between shear deformations and rigid-body rotations. The positive definiteness of the strain energy function of the modified bond model is verified. To validate the model, uniaxial tension, pure shear and pure bending tests are performed. Comparison of the particle displacements with continuum mechanics solution demonstrates the ability of the model to describe the behaviour of isotropic linear elastic material for values of Poisson’s ratio in the range $$0 \le \nu < 0.5$$ 0 ≤ ν < 0.5 .

scholarly journals Discrete Element Method- (DEM-) Based Study on the Wear Mechanism and Wear Regularity in Scraper Conveyor Chutes

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Rui Xia ◽  
Xuewen Wang ◽  
Bo Li ◽  
Xing Wei ◽  
Zhaojian Yang
Keyword(s):  
Shear Modulus ◽  
Discrete Element Method ◽  
Wear Mechanism ◽  
Poisson’S Ratio ◽  
Discrete Element ◽  
Poisson's Ratio ◽  
Remarkable Effect ◽  
Coal Particles ◽  
Scraper Conveyor ◽  
Element Method

The scraper conveyor is the key conveying equipment for fully mechanized coal mining. Wear failure of the chute is the main form of failure of the scraper conveyor. In this study, the discrete element method (DEM) was combined with the wear model. The wear mechanism and wear regularity of the chute were explored by tracking the changes in the position of coal particles during the wear process. After the validation of wear simulation, a wear test of coal for different intrinsic parameters was designed. In one wear cycle, the three-body wear was about 32.84 times that of the two-body wear. In the research range, the wear of the scraper conveyor chute increased with the increase of Poisson’s ratio, shear modulus, and density of the coal. The shear modulus showed remarkable effect on the wear of the chute, followed by Poisson’s ratio and density. There existed a linear relationship between the shear modulus and wear (R2 = 0.8232). This study is expected to be used to predict the wear of the scraper conveyor chute and provide a theoretical basis for the applicability of the chute in different mines.

Effect of Housing Support on Bearing Dynamics

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Lijun Cao ◽  
Matthew D. Brouwer ◽  
Farshid Sadeghi ◽  
Lars-Erik Stacke
Keyword(s):  
Finite Element ◽  
Elastic Material ◽  
Contact Forces ◽  
Support Structure ◽  
Linear Elastic Material ◽  
Outer Race ◽  
Linear Elastic ◽  
Elastomeric Material ◽  
Bearing Dynamics ◽  
Element Method

The objective of this investigation was to determine the effect of housing support on bearing performance and dynamics. In order to achieve the objective, an existing dynamic bearing model (DBM) was coupled with flexible housing model to include the effect of support structure on bearing dynamics and performance. The DBM is based on the discrete element method, in which the bearing components are assumed to be rigid. To achieve the coupling, a novel algorithm was developed to detect contact conditions between the housing support and bearing outer race and then calculate contact forces based on the penalty method. It should be noted that although commercial finite element (FE) software such as abaqus is available to model flexible housings, combining these codes with a bearing model is quite difficult since the data transfer between the two model packages is time-consuming. So, a three-dimensional (3D) explicit finite element method (EFEM) was developed to model the bearing support structure for both linear elastic and nonlinear inelastic elastomeric materials. The constitutive relationship for elastomeric material is based on an eight chain model, which captures hyperelastic behavior of rubber for large strains. The viscoelastic property is modeled by using the generalized Maxwell-element rheological model to exhibit rate-dependent behaviors, such as creep and hysteresis on cyclic loading. The results of this investigation illustrate that elastomeric material as expected has large damping to reduce vibration and absorb energy, which leads to a reduction in ball–race contact forces and friction. A parametric study confirmed that the viscoelastic stress (VS) contributes significantly to the performance of the material, and without proper amount of viscoelasticity it loses its advantage in vibration reduction and exhibits linear elastic material characteristics. As expected, it is also demonstrated that housing supports made of linear elastic material provide minimal damping and rely on the bearing friction to dissipate energy. A study of housing support geometry demonstrates that bearing support plays a large role on the dynamic performance of the bearing. Motion of bearing outer race is closely related to the geometry and symmetry of the housing.

Nonlinear Dynamic Analysis of Space Frame Structures by Discrete Element Method

2014 ◽  
Vol 638-640 ◽  
pp. 1716-1719 ◽  
Author(s):  
Nian Qi ◽  
Ji Hong Ye
Keyword(s):  
Discrete Element Method ◽  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Discrete Element ◽  
Internal Force ◽  
Frame Structures ◽  
Space Frame ◽  
Bond Model ◽  
Element Method

This document explores the possibility of the discrete element method (DEM) being applied in nonlinear dynamic analysis of space frame structures. The method models the analyzed object to be composed by finite particles and the Newton’s second law is applied to describe each particle’s motion. The parallel-bond model is adopted during the calculation of internal force and moment arising from the deformation. The procedure of analysis is vastly simple, accurate and versatile. Numerical examples are given to demonstrate the accuracy and applicability of this method in handling the large deflection and dynamic behaviour of space frame structures. Besides, the method does not need to form stiffness matrix or iterations, so it is more advantageous than traditional nonlinear finite element method.

scholarly journals Discrete Element Method Modelling of the Diametral Compression of Starch Agglomerates

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 932
Author(s):  
Józef Horabik ◽  
Joanna Wiącek ◽  
Piotr Parafiniuk ◽  
Mateusz Stasiak ◽  
Maciej Bańda ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Potato Starch ◽  
Discrete Element ◽  
Contact Model ◽  
Ductile Material ◽  
Diametral Compression ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Dem Simulations ◽  
Element Method

Starch agglomerates are widely applied in the pharmaceutical, agricultural, and food industries. The formation of potato starch tablets and their diametral compression were simulated numerically and verified in a laboratory experiment to analyse the microscopic mechanisms of the compaction and the origins of their breakage strength. Discrete element method (DEM) simulations were performed using EDEM software. Samples comprised of 120,000 spherical particles with radii normally distributed in the range of 5–36 μm were compacted in a cylindrical die with a diameter of 2.5 cm. The linear elastic–plastic constitutive contact model with a parallel bonded-particle model (BPM) was used to model the diametral compression. DEM simulations indicated that the BPM, together with the linear elastic–plastic contact model, could describe the brittle, semi-brittle, or ductile breakage mode, depending on the ratio of the strength to Young’s modulus of the bond and the bond-to-contact elasticity ratio. Experiments confirmed the findings of the DEM simulations and indicated that potato starch (PS) agglomerates can behave as a brittle, semi-brittle, or ductile material, depending on the applied binder. The PS agglomerates without any additives behaved as a semi-brittle material. The addition of 5% of ground sugar resulted in the brittle breakage mode. The addition of 5% gluten resulted in the ductile breakage mode.

Study on Mechanical Properties and Size Effect of Si3N4 Using Discrete Element Method

2009 ◽  
Vol 76-78 ◽  
pp. 719-724 ◽  
Author(s):  
Yuan Qiang Tan ◽  
Sheng Qiang Jiang ◽  
Cai Li ◽  
Dong Min Yang ◽  
Gao Feng Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Size Effect ◽  
Discrete Element Method ◽  
Bending Strength ◽  
Discrete Element ◽  
Poisson's Ratio ◽  
Simulation Results ◽  
Element Method

The mechanical models formed by packed circular discrete elements were used to investigate the mechanical properties of Si3N4. In these models, the distribution of elements is random in the specified region, and the average radius of elements is 6m. The main mechanical properties investigated here are Young’s modulus, compressive strength, Poisson’s ratio, fracture toughness and bending strength. Some numerical simulation analysis of the size effect of the mechanical properties in these discrete element models were carried out. The simulation results suggest that there is no obvious size effect for Young’s modulus, compressive strength and Poisson’s ratio in these discrete element models. However, for bending strength, when the number of elements in model is less than about 9000, there exists obvious size effect, with the increasing of the number of the elements, the size effect will become less and less until disappeared. The value of fracture toughness decreases with the increasing of the number of the model elements. The classical continuum fracture mechanics model about material fracture under tensile stress is also established by discrete element method. The simulation results are just the same as the simulation results of single edge notched bending (SENB) and the experimental values reported in other literatures. The results provide a more reliable foundation for the application of DEM in simulating the mechanical behaviors of advance ceramics.

Simulation of Coal Mechanical Characteristics with Discrete Element Method

2013 ◽  
Vol 671-674 ◽  
pp. 117-121
Author(s):  
Song Yong Liu ◽  
Hong Xiang Jiang ◽  
Kui Dong Gao
Keyword(s):  
Discrete Element Method ◽  
Mechanical Characteristics ◽  
Discrete Element ◽  
Particle Flow Code ◽  
Experimental Result ◽  
Uniaxial Compression Test ◽  
Micro Particles ◽  
Bond Model ◽  
Dem Model ◽  
Element Method

Base on the parallel-bond model in PFC2D(Particle Flow Code in two Dimension) used to describe the contact between coal micro-particles, DEM(Discrete Element Method) model of coal has been established, so that the coal uniaxial compression test could be investigated. By comparing the simulation result and experimental result, it is clear that DEM is suitable to simulate the mechanical characteristics and failure mode of coal. The effects of micro-parameters on the constitutive behaviors of coal simulation sample are discussed, they can provide basis for designing DEM model of other analogous coals with differenet mechanical characteristics. The microparameters of coal DEM model obtained in simulation test could be a guilding role for further developing the applicability of the DEM in coal mining, crushing and some other aspects.

Sign in / Sign up

Export Citation Format

Share Document