Coordination Number Distribution Research Articles

Investigation of Pressure Effect on Structure of 3Al2O3.2SiO2 System

The paper presents research results of structure of the Mullite system (3Al2O3.2SiO2) by Molecular Dynamics simulation (MDs) using the Born–Mayer– Huggins pair interaction and periodic boundary conditions. The simulation is performed with model of 5250 atoms at different pressure and at 3500 K temperature. The structural properties of the system have been clarified through analysis of the pair radial distribution function, the distribution of coordination number, the bond angle and the link between adjacent TOx units.

Structural and dynamic properties of aluminosilicate melts: a molecular dynamics study

In the present work, the structural and dynamic properties of aluminosilicates (Al2O3)x-(SiO2)1−x (AS) as a function of the Al2O3 concentration x are studied by means of molecular dynamics simulations. Firstly, the parametrization of the Born–Mayer–Huggins type potential developed recently for the more general CaO-Al2O3-SiO2 ternary system is assessed. Comparison of local structural properties, such as the x-ray structure factor, partial pair-correlation functions, distributions of coordination numbers and bond angles, as well as the dynamics through the viscosity and self-diffusion coefficients to experimental data and other molecular dynamics simulations found in the literature, shows that this potential is transferable to AS melts for all compositions and is more reliable than other empirical potentials used so far. The evolution of viscosity with temperature in stable liquid and undercooled regions is studied in the whole composition range and results show a progressive increase of the fragility with increasing Al2O3 content correlated to that of local structural entities like the triply bonded oxygen (TBO), AlO5 and AlO6.

Hexa ↔ tetra silicene crystal–crystal phase transition

ABSTRACTFormation of confined crystalline tetra-silicene (t-silicene) from crystalline hexa-silicene (h-silicene) via compression, and the reverse transition from the obtained t-silicene to h-silicene via heating, are studied by molecular dynamics (MD) simulations. Models contain 6400 Si atoms interacted via the new version of the Stillinger-Weber potential. While t-silicene can be obtained via compression of the crystalline h-silicene at various temperatures, we find that the best quality samples (with the highest fraction of tetragons) are obtained at high temperatures but still well below the melting point. Such t-silicene is stable over a wide range of pressure and temperature. Evolution of the structural characteristics of samples and various thermodynamic quantities upon compression is studied. Detailed analysis of the structure of t-silicene at 300 K is presented via radial distribution function, coordination number and bond-angle distributions, ring statistics and interatomic distance distribution, as well as 2D visualisation of the atomic configurations. Various types of structural defects of t-silicene are found and discussed. In addition, heating of the obtained t-silicene is shown to lead first to the reverse tetra-to-hexa silicene phase transition, and then to the melting of h-silicene. Evolution of the structural characteristics of the samples and of the thermodynamic quantities upon heating are considered. Atomic mechanism underlaying the tetrahexa phase transitions is discussed.

Nitrogenation of Amorphous Silicon : Reactive Molecular Dynamics Simulations

Since silicon nitride (SiNx) film is more stable than SiO2, silicon nitride, thus it is widely used in semiconductor industry as an insulatorlayer. The study of nitrogenation process of a-Si was performed using molecular dynamics simulations to determine the properties of the bonds created in the structure of a-SiNx. Reactive force field (Reaxff) was used as potential in this molecular dynamic simulation owing to its ability to describe charge transfer as well as breaking and formation of atomic bonds. The structure of a-Si is obtained by melting the crystalline silicon at temperature of 3500 K followed by quenching to room temperature. The nitrogenation process was carried out by randomly distributing 900 N atoms over the a-Si surface for 60 ps at temperature varied from 300 K, 600 K, 900 K, and 1200 K. The higher the temperature nitrogenation applied in the system, the more number of N atoms adsorbed, resulting in a deeper penetration depth of Nitrogen atom. Amorphization and nitrogenation changed the distribution of coordination number of Ni, Si, and O atoms. Transfer of electrons from silicon to nitrogen occurs only in the nearest nitrogen atom with silicon atom.

Hydration of Closely Related Manganese and Magnesium Porphyrins in Aqueous Solutions: Ab Initio Quantum Mechanical Charge Field Molecular Dynamics Simulation Study.

To the best of our knowledge, the current study based on ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) is the first to explore the difference in the hydration behavior between Mn(II)- and Mg(II)-associated porphyrins (Mn(II)-POR and Mg(II)-POR) in aqueous solution. The simulation study highlights similar and dissimilar characteristics of the structural, dynamical, and thermodynamical properties of these closely related metals bound to porphyrins in aqueous solution. The structural analysis is based on radial and angular distribution functions, coordination number distributions, and angular-radial distributions. Both hydrated systems demonstrate similar pentacoordinated structures formed via the axial coordination of one water molecule to the metal ion in addition to the four nitrogen atoms of the porphyrin ring. However, in the case of Mn(II)-POR, the formation of a distorted square pyramidal geometry was observed. It was envisaged as a weak coordination of the water molecule to the Mn(II) atom and thus higher atomic fluctuation for all atoms in contrast to that for the hydrated Mg(II)-POR. The dynamical data in terms of the mean residence times, velocity autocorrelation function, free energy, and other parameters revealed the difference in the metal binding effect because the Mn(II) atom was observed to inhibit H-bond formation more than the presence of Mg(II) atoms in the core of the porphyrin. The current study thus highlights the significant differences in the structural and dynamical properties of Mn(II)- and Mg(II)-associated porphyrin systems.

First-principles molecular dynamics simulations on the local structure and thermo-kinetic properties of molten magnesium chloride

MgCl2 is a salt of considerable interest for the concentrating solar thermal power (CSP) system with advantages of high operating temperature and low cost. While the value of first-principles molecular dynamics (FPMD) simulations in investigating molten salt has been illustrated in many studies, there have been very few studies on molten MgCl2 from a first-principles method. In this work, FPMD simulations are employed to investigate the local coordination structure, as well as its structural dynamics, and thermo-kinetic properties of molten MgCl2. The basic thermo-kinetic properties of density, diffusivity, and ion conductivity are calculated for pure MgCl2 at multiple temperatures. The partial radial distribution function, partial structure factor, probability distribution of coordination numbers, and bond angle distribution are also derived from FPMD simulations. FPMD simulations are found to give satisfactory structural and transport characteristics compared with experiments. This study shows that the four-fold coordinated Mg2+ cations exist in pure MgCl2 and the Mg2+ first coordination shell has more octahedral geometry with anion vacancies. In conclusion, this work shows that FPMD simulations provide an effective method for exploring molten salts, which can be used in future research on Mg-based salts.

Identification of sampling patterns for high-resolution compressed sensing MRI of porous materials: 'learning' from X-ray microcomputed tomography data.

There exists a strong motivation to increase the spatial resolution of magnetic resonance imaging (MRI) acquisitions so that MRI can be used as a microscopy technique in the study of porous materials. This work introduces a method for identifying novel data sampling patterns to achieve undersampling schemes for compressed sensing MRI (CS-MRI) acquisitions, enabling 3D spatial resolutions of 17.6 µm to be achieved. A data-driven learning approach is used to derive k-space undersampling schemes for 3D MRI acquisitions from 3D X-ray microcomputed tomography (µCT) datasets acquired at a higher spatial resolution than can be acquired using MRI. The performance of the new sampling approach was compared to other, well-established sampling strategies using simulated MRI data obtained from high-resolution µCT images of rock core plugs. These simulations were performed for a range of different k-space sampling fractions (0.125-0.375) using images of Ketton limestone. The method was then extended to consideration of imaging Estaillades limestone and Fontainebleau sandstone. The results show that the new sampling approach performs as well as or better than conventional variable density sampling and without need for time-consuming parameter optimisation. Further, a bespoke sampling pattern is produced for each rock type. The novel undersampling strategy was employed to acquire 3D magnetic resonance images of a Ketton limestone rock at spatial resolutions of 35 and 17.6 µm. The ability of the k-space sampling scheme produced using the new approach in enabling reconstruction of the pore space characteristics of the rock was then demonstrated by benchmarking against the pore space statistics obtained from high-resolution µCT data. The MRI data acquired at 17.6 µm resolution gave excellent agreement with the pore size distribution obtained from the X-ray microcomputed tomography dataset, while the pore coordination number distribution obtained from the MRI data was slightly skewed to lower coordination numbers. This approach provides a method of producing a k-space undersampling pattern for MRI acquisition at a spatial resolution for which a fully sampled acquisition at that spatial resolution would be impractically long. The approach can be easily extended to other CS-MRI techniques, such as spatially resolved flow and relaxation time mapping. LAY DESCRIPTION: Magnetic resonance imaging (MRI) is widely used to study the microstructure of, and fluid transport phenomena in porous media relevant for engineering applications. A major application is the study of water and hydrocarbon transport in porous sedimentary rocks, which typically have pore sizes smaller than 100 µm. The spatial resolution of routine MRI acquisitions, however, is limited to several hundred µm due to the relatively low sensitivity of the magnetic resonance method. Therefore, there exists a strong motivation to increase the spatial resolution of MRI by one to two orders of magnitude to be able to study these rocks at a pore scale. This work reports the initial step towards achieving this. Three-dimensional images of rock pore structure are acquired at both 35 and 17.6 µm spatial resolution. In ongoing work, these methods are now being incorporated into magnetic resonance velocity imaging methods, thereby enabling imaging of both pore structure and hydrodynamics at these much higher spatial resolutions than were hitherto possible. Although X-ray microcomputed tomography (µCT) produces high spatial resolution images, it is far more limited in being able to spatially map transport processes (i.e. flow) in porous media. This work reports a strategy for accelerating the image acquisition time such that sufficient signal-to-noise ratio (SNR) is achieved to increase the spatial resolution, that is, the voxel size within which there is sufficient SNR within the resulting image. To achieve this, a technique known as compressed sensing is used which exploits undersampling of the acquired data relative to the standard fully sampled image. In MRI, data are acquired in so-called k-space and Fourier transformed to yield the real space image. The challenge, when undersampling, is to optimise the specific points in k-space that are acquired because these will influence the quality of the resulting image. This work reports a straightforward, robust strategy for identifying the optimal sets of k-space points to acquire. The method introduced uses simulated MRI images calculated from high-resolution µCT images of the rocks of interest, from which optimised MRI sampling patterns are obtained. The method does not require any optimisation of parameters for its implementation, which is a significant advantage compared to other strategies. Moreover, we show that the pore space characteristics of the acquired MRI images are in excellent agreement with the same characteristics obtained from a high-resolution µCT image.

Structural and magnetic properties of iron nanoparticles: insights from Monte-Carlo and molecular-statics simulations

In this Letter, the structural stability, local structure characterization and magnetic properties of iron nanoparticles (FeNPs) were investigated by using a combination of Molecular Statics (MS) and Monte Carlo (MC) simulations. To do so, six kinds of spherical-shaped FeNPs with diameters in the range of 3.14 to 5.42 nm have been considered. The coordination number distribution of FeNPs obtained from the data extracted by MS simulations was exploited for performing MC simulations on the familiar Ising model. The numerical findings obtained in the current study show that the structural and magnetic properties correlate with the size of the FeNP.

Pressure-induced structural change of CaO–Al2O3–SiO2 melt: Insight from molecular dynamics simulation

Short-range and intermediate-range order structures as well as network structure of multicomponent oxide system (CaO–Al2O3–SiO2) under compression are investigated by molecular dynamics simulation (MDS). The short-range order structure is clarified via investigation of pair-radial distribution function (PRDF), coordination number distribution and topology of TOx (T = Al, Si; x = 3, 4, 5, 6) units. The intermediate-range order structure and -T-O- network structure are clarified through investigation of distribution of OMy(M = Si, Al, Ca; y = 2, 3, 4, 5) linkages and T-O-T bond angles between adjacent TOx-units. The distribution of bridging-oxygens (BO), non-bridging oxygens (NBO), and TOx-cluster size is also investigated to clarify the degree of polymerization of -T-O- network under compression. The pressure-induced structural change, incorporation mechanism of Ca2+ cations into -T-O- network, aluminum avoidance as well as the compositional and structural heterogeneities (micro-phase separation) in CaO–Al2O3–SiO2 melt are also discussed in detail.

Ab initio molecular dynamics simulation of Na-doped aluminosilicate glasses and glass-water interaction

The structure and properties of sodium aluminosilicate (NAS) glasses are investigated using ab initio molecular dynamics and density functional calculations. Four NAS glass models of about 700 atoms with composition (SiO2)0.6(Al2O3)0.4-x(Na2O)x with Na/Al ratio R = 0.0, 0.5, 1.0 and 1.5 are constructed corresponding to x = 0, 0.135, 0.20 and 0.24. Detailed information on network coordination, electronic structure, interatomic bonding and partial charge distribution, mechanical and optical properties of these models are presented and fully analyzed. The structural details for each R are discussed in terms of short- and intermediate-range order manifested in the coordination number, atomic pair and bond angle distributions. It is shown that the mechanical strength of NAS glasses decreases with increasing Na content, indicating that pure aluminosilicate glass is stronger than the alkali-doped glasses. We use the novel concept of total bond order density to characterize the internal cohesion of the NAS glasses. In the case of R = 1 NAS model, 12 water molecules are added to investigate the solvation effect and hydrolysis in NAS glass.

Physiochemical Properties and Molecular Dynamics Simulations of Phosphonium and Ammonium Based Deep Eutectic Solvents

Deep eutectic solvents (DES) are considered as second-generation ionic liquids and are used in many applications such as separation, extraction and electrochemistry. In the current work, a set of four DES is synthesized by mixing a hydrogen bond donor (HBD) (ethylene glycol/glycerol) with a quaternary ammonium or phosphonium salt or the hydrogen bond acceptor (HBA). Here the HBA, namely methyltriphenylphosphonium bromide and tetrabutylammonium bromide (TBAB), were mixed with the HBD in a molar ratio of 1:4. Fourier transform infrared and thermogravimetric analysis analysis were then carried out to understand the functional groups along with their thermal stability. NMR analysis was also used to validate the molar ratio of 1:4 in solution. Thereafter, the four DESs were simulated with molecular dynamics simulations to evaluate and measure the pure component properties of these solvents at room temperature. Thermodynamics insights such as non-bonded interaction energies, hydrogen bonds, coordination number and radial distribution functions were also discussed to understand their atomistic interactions involved in the eutectic mixtures.

Hydrogen bonding and clusters in supercritical methanol–water mixture by neutron diffraction with H/D substitution combined with empirical potential structure refinement modelling

ABSTRACTNeutron diffraction measurements of H/D isotopic substitution have been performed for seven H/D substituted methanol-water mixtures of 0.3 mol fraction of methanol (xM) under the supercritical (618 K, 100 MPa) and ambient (298 K, 0.1 MPa) conditions. The seven structure factors obtained were subjected to an empirical potential structure refinement (EPSR) modelling to derive all site-site pair correlation functions, coordination number distributions, spatial density functions, and cluster distributions. Water has a four coordinated structure in the first coordination shell under both ambient and supercritical conditions; however, the spatial density distribution of water molecules in the second coordination shell is delocalised under the supercritical condition. The mean coordination number of all atomic pairs with hydrophilic interactions decreases in the supercritical state. On the other hand, the mean coordination number of interactions between the hydrophobic part of methanol and water molecule is less sensitive to temperature. In the supercritical condition, water clusters with a wide size distribution are generated in a methanol-water mixture as well as in pure water. Since the critical temperature of a methanol-water mixture is lower than that of pure water, it can be concluded that the addition of methanol can generate fragment water clusters at a lower temperature.

Structural and thermodynamic properties of two-dimensional confined germanene: a molecular dynamics and DFT study

Formation of two-dimensional (2D) confined germanene upon cooling from the 2D liquid state is studied via molecular dynamics (MD) simulation. Our model containing 104 Ge atoms is cooled from to with Stillinger-Weber (SW) potential to obtain a honeycomb structure. Structural and thermodynamic properties upon cooling from the liquid state are investigated in details. The crystallization of germanene exhibits a first-order-like phase transition. Structural properties of germanene obtained at are investigated by a combination of coordination number, ring and bond-angle distributions, and 2D visualization of atomic configuration analysis. Our MD simulation provides helpful insights into the atomic mechanism of the formation and thermodynamics of this 2D material. Besides, the DFT calculation is used to confirm the existence of 2D Ge buckling model, to study the electronic structure and properties of the model. DFT calculations show that buckling germanene is stable with a band gap of around 0.850 eV.

Heterogeneous–homogeneous transition and anomaly of density in SPC/E water examined by molecular dynamics simulations

Molecular dynamics (MD) simulations of SPC/E water have been performed to characterize anomaly of water such as density maximum and minimum observed in temperature dependence and polyamorphism related them.Two important factors to explain the density anomaly of the system are considered in the present work. First, the changes in network of hydrogen bonds of water with temperatures is characterized by the thermodynamical quasi-equilibration among different kinds of local polyhedra (O atoms around O atom connected by hydrogen bonding), where applicability of the van’t Hoff analysis is confirmed. As a result of this treatment, change of water structure with decreasing temperature can be characterized as the transition from “heterogeneous network” to “homogeneous network”. This explanation differs from that based on simple mixing of two (or several) components nor that by development of typical hydrogen networks only.Second, one needs to consider oscillating structures of coordination shells. Quantitative comparison of local density with different length scales revealed that inclusion of longer length scale structures is required for convergence of the density. Namely, the density of water is not a simple sum of the different size of units but is determined by the coordination shells including sparse regions.These concepts are also useful to characterize the polyamorphism of water. With increasing pressure at 200 K, the transition from “homogeneous network” to “heterogeneous network” occurs. The change corresponds to that from “low density water (LDW)” to “high density water (HDW)”, which accompanied with a large change of distribution of coordination numbers in longer length scales.

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Pore systems become very complex in heterogeneous reservoirs such as low-permeability and tight sandstones for macropores and micropores both exist in such reservoirs. Although the large pores may control the reservoir quality and rock properties, micropores always can affect the geometric and transport properties of the pore systems. In this paper, thus, such an effect is studied comprehensively. As such, low- and high-resolution computed tomography (CT) scanning experiments were carried out on the same low-permeability sandstone in order to obtain the low- and high-resolution digital rock (LRDR and HRDR) images, respectively. The impacts of micropores on properties of pore systems were investigated based on digital rock analysis of the LRDR and HRDR images for two samples. In this study, the micro-porosity is defined as the pores and throats which can be covered by the HRDR images but cannot be covered by the LRDR images. The results show that there are better connectivity, smaller tortuosity and higher heterogeneity for the HRDR image, compared to the LRDR image of the same rock. The fractal analysis of pore space indicates that the surface of the pore space with micropores becomes rougher. Moreover, we found that the micropore space plays a more significant role in the throats than the pores by comparing the pore and throat size distributions of the LRDR and HRDR images. In addition, the micropores can lead to a decrease in the average shape factor and smoothness of the boundary of pores and throats. It was also found that micro-porosity not only increases the average coordination number but also increases the number of isolated pores according to the coordination number distributions. Finally, the results of single- and two-phase flow simulation show that the absolute permeability and formation factor become larger and smaller, respectively, for the pore systems with micropores. This result reveals that micropores can improve the transportability and connectivity of the pore systems.

Molecular dynamics simulation of SiC removal mechanism in a fixed abrasive polishing process

Abstract Precision polishing of mono-crystalline SiC wafers on a fixed abrasive pad is investigated by double-nano-abrasives cutting at micro/nano scale in this report. Prior to this report, a single abrasive approach in molecular dynamics simulation had been employed to illustrate the material removal mechanism in SiC polishing process, which is quite different from the real situation of the fixed abrasive polishing process. Cutting depth and spacing of abrasive particles in a fixed abrasive pads were tested to gain insights on phase transformation, subsurface damage, surface quality, material removal and friction characteristics of polished SiC wafers by molecular dynamics simulation. By following the coordination number and radial distribution function, we clearly see that the number of phase transformation atoms caused by cutting and abrasion increases with the cutting depth of nano-abrasives on the surface of SiC workpiece. Simulation results also suggest that t he phase transformation of the SiC crystal phase increases with the lateral spacing of abrasive particles in pads, while does not change much with the increase of the longitudinal spacing. It is also found that the deeper the abrasive cutting depth, the deeper subsurface damage, resulting more materials’ removal from SiC workpiece. The lateral and longitudinal abrasive spacings lead to little change the depth of subsurface damage on the wafer in MD simulation for a fixed double abrasive polishing. The surface roughness is better with the larger lateral abrasive spacing, but no clear correlation with the longitudinal abrasive spacing.

On the transferability of interaction potentials for condensed phases of silicon

A systematic comparison of structural, thermodynamical and kinetic properties of silicon by molecular dynamics simulation was done using five interatomic potentials, namely the Stillinger-Weber (SW) model, the environment-dependent interatomic potential (EDIP), two versions of the modified embedded-atom method (MEAM-1 and MEAM-2) and the angular dependent potential (ADP). This benchmark allows us to determine which interatomic potential is the most adequate to simulate this material. Structural properties and the vibrational density of states (VDOS) for diamond-structure crystal and amorphous phases were studied. We also obtained the diffusion coefficient for the liquid phase. For the models able to describe crystallization from the melt, the interfacial free-energy was also computed. Results show that the SW potential outperforms the remaining models in several aspects including the structure factor and the coordination number distribution of the liquid and the melting temperature. MEAM-2 follows as the second best model due to its ability to reproduce the crystal-liquid interfacial free-energy and the structure factor and the VDOS for the amorphous phase. EDIP, MEAM-1 and ADP models can reproduce some physical properties but they lack transferability, which is a key aspect of a good interatomic potential.

Integrated pore-scale characterization of mercury injection/imbibition and isothermal adsorption/desorption experiments using dendroidal model for shales

Distinct from conventional reservoirs, shale formations have limited pore connectivity and unique pore spatial-distributions. Consequently, theoretical pore-network models developed for conventional formations are not representative of the pore topology within unconventional rocks. This paper presents a theoretical pore-network model, dendroidal model, based on the analysis of reconstructed pore-scale model extracted from Scanning Electron Microscope images. Dendroidal model is a semi-acyclic model, which characterizes the poor connectivity of void space without sacrificing the interaction between main flow paths. Dendroidal model infers pore-body distribution based on the hysteresis effect of isothermal adsorption/desorption measurements and characterizes pore-throat distribution using mercury injection capillary pressure data. The use of dual-compressibility model in pore-network model construction eliminates the effect of compressibility of both void space and matrix. Total organic carbon (TOC) content and minerology determine the composition of pore bodies and pore throats. The difference in mercury intrusion and extraction caused by trapping hysteresis and contact-angle hysteresis affects the stochastically distributed parameters, including pore-throat length, pore-throat cross-sectional morphology, coordination number and pore-body spatial distribution. We used shale core samples from Marcellus and Wolfcamp formations to validate the dendroidal models by calculating the absolute permeability without slippage effect. This newly developed pore-network model integrates aforementioned seven distinct types of experimental data to capture the realistic pore structures within shales.

Tetra-SiC – New allotrope of 2D silicon carbide

Formation and atomic structure of two-dimensional (2D) tetra-SiC (containing entirely tetragons) are studied by molecular dynamics (MD) simulations. Models contain 6400 atoms (3200 Si atoms and 3200 C ones) interacted via so-called Vashishta’s interatomic potentials. We compress initially perfect planar SiC with honeycomb structure (hexa-SiC) at three different temperatures (below and above melting point) step by step and we find hexa-tetra 2D SiC phase transition. Tetra-SiC sample obtained at temperature significantly below melting point exhibits the best quality which contains the lowest concentration of defects (non-tetragons). This tetra-SiC is stable over a wide range of density and temperature. On the other hand, we cool the obtained tetra-SiC to room temperature and it is also stable at room temperature. Evolution of various structural and thermodynamic quantities upon compression is studied and we find that it exhibits a first-order-like phase transition behavior. Detailed analysis of structure of the obtained tetra-SiC is shown via coordination number and bond-angle distributions, ring statistics, 2D visualization of atomic configurations etc. Moreover, important quantities of mechanical behaviors such as Young modulus and Poisson’s ratio of the sample are found and discussed. DFT calculations show that flat tetra-SiC is stable with a band gap of around 0.97 eV. Our prediction of the existence of this new allotrope of 2D SiC can serve as a guide for further investigation in this direction including fabrication of material in practice.

Discrete element modelling of the mechanical behaviour of a sand-rubber mixture containing large rubber particles

Sand-rubber mixtures (SRMs) are newly developed geomaterials that have been widely applied in geotechnical engineering. However, the precise particle-level mechanical properties of SRMs are not yet fully understood. The present study conducted numerical simulations of triaxial tests of SRM samples containing large rubber particles employing the discrete-element method. This method allows the tracking of many important microstructural quantities, including the distribution of contact normal orientations, coordination number, particle displacement, particle sliding, and rolling during shearing. Numerical simulations showed that the contact normal anisotropy along the loading direction is clearly weakened by the addition of rubber particles. Rubber-rubber contacts are found to mainly participate in weak force networks. With an increase in the rubber content, rubber particles gradually participate in strong force chains, resulting in a more homogeneous magnitude of contact forces in the SRM. It is also observed that the rubber inclusions obviously change the pattern of strain localisation in the displacement field, indicating that rubber particles can prevent the formation of shear bands. The addition of rubbers also restrains the particle rearrangement effect by restricting interparticle rolling and sliding motion on a microscale. These findings expand the current understanding of the mechanical behaviours of SRMs.