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ABSTRACT We propose a smoothed particle hydrodynamics (SPH) model bridging the gap between solid‐ and fluid‐like behaviour observed in granular materials. The key innovation of the proposed approach lies in the decomposition of the stress gradient into rate‐independent and rate‐dependent parts, which are governed by the hypoplastic and μ(I)$\mu (I)$ constitutive relations, respectively. By using the proposed approach, we successfully capture the transition between solid‐ and fluid‐like flow regimes in granular materials. The proposed SPH scheme is rigorously validated through the examination of various boundary value problems, including the collapse of a granular column, Taylor–Couette flow, and silo flow. [ABSTRACT FROM AUTHOR]

In this work, we propose an efficient smoothed particle hydrodynamics (SPH) method for simulating laser powder bed fusion (LPBF). The multi-physics process of LPBF, including the heat transfer and phase change with complex boundaries, is accurately resolved by a novel heat source model and a modified continuous surface force based on a corrected surface delta function. Moreover, we also develop an efficient tensile instability control algorithm for preventing the pressure oscillations. The present method is implemented in a GPU-accelerated framework, and its performance is well demonstrated by simulating the LPBF processes with both single-layer and multi-layer powder beds (with the help of surface reconstruction). The numerical results are compared well with the experimental ones which clearly verify the ability of the present method in capturing the complex physical phenomenon of LPBF. [ABSTRACT FROM AUTHOR]

Functionally graded (FG) carbon nanotubes (CNTs) reinforced composite possessing continuously varied material properties have received extensive concern in the area of aviation, automotive, military, and spaceflight. The nonlinear bending of FG CNT composite is performed by developing a novel meshless model on the base of Smoothed Particle Hydrodynamics (SPH) method. The equivalent temperature relative material properties of composite is established in the light of the extended rule of mixture model. Different gradient dispersions of CNTs are taken into account and modeled. The governing equations are explored using the Mindlin theory and discretized though a symmetric SPH method with high prediction ability. The developed model is verified by analyzed several examples and compared to the solution obtained in literature. Influences of CNT dispersion, content, plate aspect ratio, boundary conditions and lamination angle on the bending response are elaborated. The present study provides an alternative potential method to solve the mechanical performances of FG CNT composites based on the meshless SPH formulation. Highlights: Thermo‐mechanics of FG‐CNTRC is firstly solved by SPH method.The model is verified by solving the benchmarks in literature.Nonlinear bending behaviors of FG‐CNTRC are demonstrated.The minimum deflection take place in FG‐X type composite.For laminate plate, the smallest deformation occurs in 0° CNTRC. [ABSTRACT FROM AUTHOR]

Shock wave propagation and their damage to solid structures, which involve complex multiphase and multiphysics phenomena, are difficult problems to address. In this paper, a three-dimensional graphics processing unit (GPU)-accelerated finite difference-smoothed particle hydrodynamics (FD-SPH) method was developed for the prediction of strongly compressible fluid flow and strong fluid-structure interactions. The conventional mesh-based finite difference method was used to simulate shock wave propagation, while the smoothed particle hydrodynamics method was employed to predict the dynamic behavior of solid materials. In addition, the immersed boundary method (IBM) was implemented in the GPU-accelerated FD-SPH solver for the boundary treatment of the interface between solid and fluid materials. Four numerical cases, namely shock-cylinder obstacle interaction, elastic panel deformation induced by shock wave propagation, the response of stainless steel tubes under internal blast loading, and the damage of blast loading on reinforced concrete slab, were conducted for verification of the GPU-accelerated FD-SPH solver. The numerical results were compared against the available experimental data, which shows that the GPU-accelerated FD-SPH solver is capable of capturing the shock wave propagation and its damage to structures very well. • A GPU accelerated coupled FD-SPH method is developed to solve strong fluid-structure interaction problems. • The immersed boundary method is used in the solver to impose boundary conditions on the fluid-structure interface. • The propagation of shock waves and its damage to the structure is well captured. [ABSTRACT FROM AUTHOR]

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Numerical simulations were conducted to investigate the wave features of subaerial granular landslide-generated impulse waves and their impact on slopes. A numerical solution was obtained by coupling smoothed particle hydrodynamics (SPH) and the discrete element method (DEM). Several predictive equations were tested for their applicability in predicting the maximum crest amplitude of impulse waves generated by slides of different shapes. The results indicated that the predictive model developed by Heller and Hager, utilising slide centroid impact velocity, showed favourable prediction accuracy for the maximum crest amplitude, almost independent of the slide shape at impact. Regarding the leading wave, although the wave profile and velocity distribution deviated significantly from a solitary wave of the same wave amplitude, the maximum run-up could be satisfactorily estimated using solitary wave theory. In addition, the increase in the maximum dynamic forces exerted by the impulse waves on the slope followed a power law with the incident wave amplitude. [ABSTRACT FROM AUTHOR]

A numerical study based on a two-dimensional two-phase SPH (Smoothed Particle Hydrodynamics) model to analyze the action of water waves on open-type sea access roads is presented. The study is a continuation of the analyses presented by Chen et al. (2022), in which the sea access roads are semi-immersed. In this new configuration, the sea access roads are placed above the still water level, therefore the presence of the air phase becomes a relevant issue in the determination of the wave forces acting on the structures. Indeed, the comparison of wave forces on the open-type sea access roads obtained from the single and two-phase SPH models with the experimental results shows that the latter are in much better agreement. So in the numerical simulations, a two-phase δ-SPH model is adopted to investigate the dynamical problems. Based on the numerical results, the maximum horizontal and uplifting wave forces acting on the sea access roads are analyzed by considering different wave conditions and geometries of the structures. In particular, the presence of the girder is analyzed and the differences in the wave forces due to the air cushion effects which are created below the structure are highlighted. [ABSTRACT FROM AUTHOR]

The study of red blood cell dynamics is an important research field. Understanding physiologic and pathologic characteristics of red blood cell can provide a new perspective to diagnosis and treatment of several diseases. In this work, a numerical model has been developed using the smoothed particle hydrodynamics which is a Lagrangian, meshless particle method to investigate red blood cell dynamics in oscillatory flow. The developed model is parallelized in graphic processing units using Compute Unified Device Architecture developed by NVIDIA that resulted in a seventeen fold reduction in computational cost. The effect of frequency of oscillation and phase difference on red blood cell dynamics is investigated. In addition, the dynamics of healthy and infected red blood cell in oscillatory flow is compared in this work to understand relevance of oscillatory flow in cell separation devices. [ABSTRACT FROM AUTHOR]

The helical anchor foundation is driven into the soil under the combined action of torque and vertical pressure. The installation process involves a significant deformation of the soil, which is difficult to simulate numerically using the traditional finite element method. As a meshless method, Smoothed Particle Hydrodynamics (SPH) is very suitable for simulating large deformation problems. In this paper, the SPH meshless method and traditional finite element method are used to simulate the installation and pulling process of helical anchor foundations in sandy soil. The variations in installation force, installation torque, ultimate uplift capacity, and torque correlation factor under different advancement ratios were studied. The research results indicate that using a low advancement ratio for installation can significantly reduce the installation force and torque of the helical anchor and positively affect the ultimate uplift capacity. Moreover, the torque correlation factor is also influenced by the advancement ratio. Using the torque correlation factor value obtained from the "pitch matching" installation to predict the ultimate uplift capacity at other advancement ratios may result in an overestimation. [ABSTRACT FROM AUTHOR]

Railway embankments in seismically active areas are prone to earthquake-induced damage. In many instances globally, such damage has led to substantial economic losses. Serviceability assessment of these embankments is pivotal in ascertaining better performance during earthquakes. This work presents a physics-based approach to assess the serviceability of railway embankments subjected to strong ground motions. A series of nonlinear dynamic analyses are performed to evaluate the failure mechanism, progression of the failure plane, accumulation of plastic strain, and deformations of a railway embankment using the framework of smoothed particle hydrodynamics (SPH). The embankment and its underlying foundation are treated as a layered domain, and peak acceleration within each layer is determined through the site-specific nonlinear ground response analysis. The vulnerability assessment of the embankment is carried out considering the vertical displacement of the crest, accumulation of plastic strain, and post-failure scenario under site-specific ground motion characteristics. The vulnerability of the embankment is further quantified through fragility analysis by considering various damage levels. Fragility analysis is carried out using incremental dynamic analysis (IDA) against peak ground acceleration (PGA) of input ground motions as the key hazard indicator. The robustness of the developed vulnerability evaluation framework is also scrutinized through a sequence of stochastic analyses, considering the variability in ground conditions to enhance engineering assessment. The embankment is seen to experience a maximum vertical deformation of 0.05 m at the crest when initial signs of plastic strain development are observed, with deformation increasing to around 0.1 m for moderate damage levels and reaching up to 0.2 m at the point of slope failure. Fragility curves reveal that the right edge of the embankment reaches the first damage level at a PGA of approximately 0.12 g, followed by higher damage levels at PGA's as high as 0.8 g, for a 100% probability of extensive damage. Stochastic analysis shows that the probability of maximum vertical displacement exceeding deterministic values is about 78.47%, with maximum deviations of 2.599 m. For plastic strain, the probability of exceeding deterministic values is 78.49%, with maximum deviations of 13.08. These findings underscore the importance of considering site-specific conditions and the variability of soil properties in seismic assessments to ensure accurate and reliable serviceability evaluations of railway embankments. [ABSTRACT FROM AUTHOR]

The in-vessel retention through external reactor vessel cooling (IVR-ERVC) strategy is a key management strategy for early termination of a nuclear severe accident that can threaten the integrity of the reactor vessel. To simulate the physical phenomena of the molten corium, the smoothed particle hydrodynamic (SPH) method is utilized in this study. The SPH method is a Lagrangian computational fluid dynamic (CFD) method that can simulate multi-fluid stratification, turbulence, natural circulation, radiative heat transfer, thermal ablation, and crust formation. To address the external vessel cooling, it is coupled with a conventional 1-D nuclear system analysis method. The 1-D system analysis code can calculate the two-phase natural circulation of cooling water and the convective heat transfer on the external reactor vessel wall. These two simulation codes exchange the temperature and heat flux of the reactor vessel outer wall. This study numerically simulated the IVR-ERVC strategy for a Korean high-power reactor and compared it with the traditional lumped parameter method (LPM). Unlike LPM, this study provides localized detailed data about the thermal hydraulic behavior of molten corium and visualization of phenomena in the IVR-ERVC strategy. This enhances our understanding of the phenomena in IVR-ERVC strategy and introduces new perspectives.

Abstract The drainage and imbibition processes are critical mechanisms in petroleum engineering. These processes in a porous medium are controlled by surface forces and pressure gradients. The study of these processes in the pore scale by common simulators always has limitations in multiphase flow modeling. Also, obtaining relative permeability curves through laboratory analysis requires expensive equipment. Additionally, these laboratory experiments are quite expensive and may introduce significant uncertainties. For this purpose, this study investigated the creation of relative permeability curves and their effect on oil production. Initially, single-phase fluid and two-phase droplet flow within a fracture with both soft and rough surfaces were utilized to validate the formulation of the Smoothed Particle Hydrodynamics (SPH) method. Then, by using three randomly constructed porous medium models, the imbibition and drainage processes have been studied. Finally, sensitivity study has been carried out on critical parameters related to fluid flow dynamics in the porous environment, including pressure changes, wettability, and heterogeneity in drainage and imbibition processes. The simulation results were consistent with current theories; therefore, it is reasonable to consider SPH to characterize the fluid flow dynamic during the drainage and imbibition processes. According to sensitivity studies, pressure gradient (residual saturation of displaced fluid is about 5.65% and 8.44%) and heterogeneity (the residual saturation of the displaced fluid was 4.04% and 2.98%) have the largest impact on flow modeling in both drainage and imbibition processes and wettability (the residual saturation became 36.62% and 5.12%) has significant effect on the drainage process through porous medium. In general, fluid flow dynamic studies can be performed using the SPH method to model fluid flow in simple and complex porous medium under various flow conditions. The SPH method can also be used as an applicable tool to investigate the hydrocarbon fluids flow within larger geometries in the future.

ABSTRCT: To enhance the bird strike resistance of fixed-wing aircraft wings, a combined computational approach integrating nonlinear solid mechanics and fluid dynamics was employed to analyze the bird strike characteristics of both traditional aluminum alloy skins and novel composite materials skins. Additionally, a standardized procedure was established to simulate aircraft structural damage more comprehensively, swiftly, and accurately during bird strikes, along with diagnostic analysis of flow field changes near the wing post-impact. This method not only quantifies wing strength damage but also establishes corresponding relationships between damage severity and aerodynamic performance degradation. The research findings indicate that the deformation of composite material skin wings is only a quarter of that of aluminum alloy skin wings. Composite material skins absorb less harmful energy compared to aluminum alloy skins, with consistently lower stiffness reduction rates at various bird strike velocities. Velocity distribution on deformed wings with composite material skins exhibits minimal deviation compared to normal wings, thereby preventing airflow separation. The research results provide more comprehensive guidance for the selection of materials for bird strike resistance of aircraft wings and the airworthiness evaluation after bird strikes. Highlights: This paper establishes a standardized procedure that enables a more comprehensive, faster, and higher-precision simulation of structural damage to the aircraft during a bird strike on the wing and allows for the diagnostic analysis of the flow field changes near the wing after bird strike. By coupling nonlinear solid mechanics and fluid dynamics computational methods, the aerodynamic performance of the wings at different angles of attack post-deformation is investigated. This approach not only quantifies the strength damage to the wings but also establishes corresponding relationships between the degree of damage and the deterioration in aerodynamic performance. The research yields insights into the aerodynamic performance degradation patterns with varying angles of attack for both composite material skin and aluminum alloy skin deformed wings. These findings can serve as valuable references for pilots in emergency situations, aiding in their decision-making regarding aircraft control. [ABSTRACT FROM AUTHOR]

Sediment scour numerical simulation plays a critical role in the design of water-resistant foundation engineering, and this paper addresses a significant gap in most related studies, which often overlook the transformation of sediment and struggle to identify the actual riverbed obscured by yielding bed and suspended load. To tackle this challenge, a comprehensive sediment model based on the meshless Smoothed Particle Hydrodynamics (SPH) method was developed. Firstly, to enhance computational efficiency and mitigate the high cost of Fluid-Solid Interaction (FSI) between water and sediments, cohesionless sediment grains were modelled as non-Newtonian fluids, with yield strength determined according to a combined strength criterion. Subsequently, sediment transformation and identification were determined based on sediment particle velocity and shear stress, with the seepage force driving yield sediment particle motion at the interface. The effectiveness of this comprehensive sediment model was validated through comparison with three scour experiments. The results show better agreement between the model and experimental data, with a root-mean-square error of less than 2.17% in scour morphology simulation and successful identification of the actual post-scouring bed surface in each case. However, the free surface simulation in this model still exhibits slight error, with a root-mean-square error of less than 8.35%. [ABSTRACT FROM AUTHOR]

We propose a new approach for performing drained and undrained loading of elastoplastic geomaterials over large deformations using smoothed particle hydrodynamics (SPH), a meshfree continuum particle method, combined with the modified Cam Clay (MCC) model of critical state soil mechanics. The numerical approach draws upon a novel one‐particle two‐phase penalty‐method based formulation for handling undrained loading in saturated soils, which allows tracking of the buildup of pore‐water pressures under combined shearing and compression. Large‐scale parallelized simulations are employed to accommodate a significant number of degrees of freedom in a three‐dimensional setting. After verification and benchmark testing, the SPH based formulation is used to analyze the propagation of reverse faults through fluid‐saturated clay deposits and the rupture of strike‐slip faults across earthen embankments. The computational methodology tests the robustness of the meshfree approach in situations where the soil tends to dilate on the 'dry' side of the critical state line and to compact on the 'wet' side, but cannot, because of the incompressibility constraint imposed by undrained loading. Our results extend the current understanding of fault rupture modeling and further demonstrate the potential of our framework together with the SPH method for large deformation analyses of complex problems in geotechnics. [ABSTRACT FROM AUTHOR]

Concrete, ceramics, rocks, metal-matrix composites, titanium alloys and other hard-to-cut materials are frequently cut using the non-traditional cold processing method known as abrasive water jet machining (AWJM). A virtual machining system is proposed in the study to minimize roughness of surface and residual stress during AWJM of titanium alloy Ti6Al4V. The water and workpiece are simulated in virtual environments using the smoothed particle hydrodynamics (SPH) approach and finite element method, respectively. Then, the Johnson–Cook law model of titanium alloy is used to obtain the cutting temperature during cutting operations. To calculate residual stress during the AWJM operations, the finite element method is then utilized. The Taguchi optimization method is implemented to minimize surface roughness and residual stress in AWJM operations. Thus, the optimized machining parameters such as water jet pressure, traverse speed, abrasive mass flow rate and standoff distance are calculated to minimize the surface roughness and residual stress during the AWJM of titanium alloy Ti6Al4V. Experimental and computational examinations are carried out in order to validate the effectiveness and efficiency of proposed virtual machining system in minimization of surface roughness and residual stress during abrasive waterjet cutting of titanium alloy Ti6Al4V. As a result, by using the optimized machining parameters, 23.7% and 27.1% reduction in the measured and predicted residual stress of sample machined part are obtained. Also, the sample machined part's surface roughness is reduced by 26.7% and 27.9%, for the measured and predicted surface roughness of sample machined part, respectively. So, the quality and reliability of the machined parts can be enhanced using the developed virtual machining system in the study to minimize the surface roughness and residual stress in AWJM operations. [ABSTRACT FROM AUTHOR]

Magnetic pulse welding of Cu/Ti tubular joint is performed by creating intense transient magnetic fields that drive the metal components together at high velocity. This leads to interfacial waviness due to Kevin–Helmholtz instability and emission of a metal jet. The process is simulated using a a two-stages modeling methodology in which magnetic pressure at copper tube is calculated from an electromagnetic code and fed to a meshless hydrocode. Key features of the interfacial morphology and jet emission are reproduced. Jet is found to be dominated by titanium and a linear velocity profile observed. [ABSTRACT FROM AUTHOR]

This paper introduces a new hypoplastic model characterized by a simple and elegant formulation. It requires only 7 material parameters to depict salient mechanical behaviors of granular materials. The numerical implementation employs an explicit integration method, enhanced by a best-fit stress correction algorithm in a smoothed particle hydrodynamics code. The performance of this model in capturing soil behavior across a range of scenarios is demonstrated by conducting various numerical tests, including triaxial and simple shear at low strain rates, as well as granular collapse, rigid penetration and landslide process at high strain rates. [ABSTRACT FROM AUTHOR]

The laser-beam powder bed fusion process for metals, commonly abbreviated as PBF-LB/M, is a widely used process for the additive manufacturing of parts. Numerical simulations are useful to identify optimal process parameters for different materials and to obtain detailed insights into process dynamics. The present work uses a single-phase incompressible Smoothed Particle Hydrodynamics (SPH) scheme to model PBF-LB/M which was found to reduce the required computational time and significantly stabilize the partially violent flow in the melt pool in comparison to a weakly compressible SPH approach. The laser-material interaction is realistically modelled by means of a ray tracing method. An approach to model the effective thermal coductivity of the powder bed is proposed. Excellent agreement between the simulation results and experimental X-ray analyses of the transition from conduction melting mode to keyhole mode including geometric properties of the vapor depression zone was found. These results prove the usability of SPH as a high precision simulation tool for PBF-LB/M. [ABSTRACT FROM AUTHOR]

The collapse behaviour of granular materials is influenced by many factors, such as aspect ratio and inter-particle friction. However, the specific impact of basal to grain friction on column collapse remains poorly understood. In this study, we systematically analyse the effect of basal friction on gravity-driven granular column collapse using a validated smoothed particle hydrodynamics (SPH) model. The results show that such the basal friction coefficient does influence deposit geometry, deposit morphology, and energy conversion. To predict the run-out distance, we propose a modified formula that incorporates the basal friction coefficient, considering two extreme cases, i.e., μ = 0 and + ∞. The basal friction also exerts an influence on the final height, with higher friction coefficients resulting in greater final heights. As the friction coefficient increases, the aspect ratio corresponding to the maximum final height also increase. However, we observe a convergence of the effect of basal friction on the final height when μ > 0.5. Furthermore, the competition mechanism between the initial column aspect ratio and basal friction coefficient reveals two transition zones between the three main deposit regimes (regime I, regime II, and regime III). This suggests that the deposit regime can be influenced by basal friction. Additionally, an analysis of energy conversion supports many of the conclusions provided in the text and exhibits the interplay between pressure gradient and base friction. Our findings show the clear influence of basal friction on the collapse behaviour of granular materials and therefore should be carefully considered in future studies. [ABSTRACT FROM AUTHOR]

Pre-sowing mechanical tillage in crop fields is a primary task and important aspect of crop production. The interaction between the tillage components and the soil plays a crucial role in determining the energy consumption of tillage machinery. Therefore, it is essential to investigate soil-tool interaction mechanisms and optimize tool design for energy savings in soil cutting. The study employed the Smoothed Particle Hydrodynamics (SPH) method to investigate the soil cutting process of a typical rotary blade. The article describes the principles and modeling process of the SPH method in detail. It includes the selection of constitutive models, boundary treatments, and particle conversion. A high-precision soil-tool interaction model was established to analyze the deformation zone of the soil, cutting energy, cutting resistance, and soil particle movement. Orthogonal simulation experiments and response surface methodology were used to optimize key design parameters of the rotary blade considering both the reduction in cutting power consumption and the impact on the structural performance of the tool. The optimal parameters were determined as follows: a bending point included angle of 30°, a side cutting edge bending line direction angle of 51°, and a bending angle of 120°. These parameters resulted in a minimum power consumption of 0.181 kW while meeting the required structural performance. Finally, experiments were conducted on field rotary tillage, and the measured power consumption showed a deviation of 7.1% from the simulated power consumption. The optimized power consumption was reduced by 9.52% compared to the initial power consumption, validating the accuracy of the simulation process and the effectiveness of energy savings. [ABSTRACT FROM AUTHOR]

Scientific computing libraries, whether in-house or open-source, have witnessed enormous progress in both engineering and scientific research. Therefore, it is important to ensure that modifications to the source code, prompted by bug fixing or new feature development, do not compromise the accuracy and functionality that have been already validated and verified. This paper introduces a method for establishing and implementing an automatic regression test environment, using the open-source multi-physics library SPHinXsys as an illustrative example. Initially, a reference database for each benchmark test is generated from observed data across multiple executions. This comprehensive database encapsulates the maximum variation range of metrics for different strategies, including the time-averaged, ensemble-averaged, and dynamic time warping methods. It accounts for uncertainties arising from parallel computing, particle relaxation, physical instabilities, and more. Subsequently, new results obtained after source code modifications undergo testing based on a curve-similarity comparison against the reference database. Whenever the source code is updated, the regression test is automatically executed for all test cases, providing a comprehensive assessment of the validity of the current results. This regression test environment has been successfully implemented in all dynamic test cases within SPHinXsys, including fluid dynamics, solid mechanics, fluid-structure interaction, thermal and mass diffusion, reaction-diffusion, and their multi-physics couplings, and demonstrates robust capabilities in testing different problems. It is noted that while the current test environment is built and implemented for a particular scientific computing library, its underlying principles are generic and can be easily adapted for use with other libraries, achieving equal effectiveness. [ABSTRACT FROM AUTHOR]

Tensile instability is one of the major obstacles to particle methods in fluid simulation, which would cause particles to clump in pairs under tension and prevent fluid simulation to generate small-scale thin features. To address this issue, previous particle methods either use a background pressure or a finite difference scheme to alleviate the particle clustering artifacts, yet still fail to produce small-scale thin features in free-surface flows. In this article, we propose a dual-particle approach for simulating incompressible fluids. Our approach involves incorporating supplementary virtual particles designed to capture and store particle pressures. These pressure samples undergo systematic redistribution at each time step, grounded in the initial positions of the fluid particles. By doing so, we effectively reduce tensile instability in standard SPH by narrowing down the unstable regions for particles experiencing tensile stress. As a result, we can accurately simulate free-surface flows with rich small-scale thin features, such as droplets, streamlines, and sheets, as demonstrated by experimental results. [ABSTRACT FROM AUTHOR]

In this paper, the response of different bird constitutive models under high-speed impact was analysed by numerical methods, and the accuracy of the bird models was evaluated based on the experiments of bird impact on titanium alloy plates. Firstly, the finite element software LS-DYNA was used to build the model of bird impact on a titanium alloy plate. The impact deformation of the plate was investigated, and the numerical results were compared with the experiments. Next, the time histories of kinetic energy and impact force for different models were analysed. Finally, the deformation of the birds during the impact was compared. The results show that the hydrodynamic fluidic material model has the advantage in predicting the displacement of the plate, especially at the impact velocity of 180 m/s, and the predicted displacement results match the experiment the best. The kinetic energy of the four material models can reflect the displacement results. The kinetic energy of the hydrodynamic fluidic material model decays slowly, with the most remaining kinetic energy and the largest plate displacement; the kinetic energy of the elastic-plastic model decays fastest, with the minor remaining kinetic energy and the smallest plate displacement. [ABSTRACT FROM AUTHOR]

Residual strength is an indispensable factor in evaluating rock fracture, yet the current Smoothed Particle Hydrodynamics (SPH) framework rarely considers its influence when simulating fracture. An improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods (i.e., the discrete element method). Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and shear. Bond fracture mark ψ was introduced to improve the kernel function after tensile damage, and the calculation of residual stress after the damage was derived after shear damage. Numerical simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence, even fracture and separation. The results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock slopes. The residual stress of brittle tock is correctly captured by the improved SPH method. The improved SPH method that considers residual strength shows an approximately 13% improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength, as validated against analytical solutions. We infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses. [ABSTRACT FROM AUTHOR]

In this study, a common-node DEM-SPH coupling model based on the shared node method is proposed, and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics (DS-SPH) method is developed using LS-DYNA software. The DEM and SPH are established on the same node to create common-node DEM-SPH particles, allowing for fluid–structure interactions. Numerical simulations of various scenarios, including water entry of a rigid sphere, dam-break propagation over wet beds, impact on an ice plate floating on water and ice accumulation on offshore structures, are conducted. The interaction between DS particles and SPH fluid and the crack generation mechanism and expansion characteristics of the ice plate under the interaction of structure and fluid are also studied. The results are compared with available data to verify the proposed coupling method. Notably, the simulation results demonstrated that controlling the cutoff pressure of internal SPH particles could effectively control particle splashing during ice crushing failure. [ABSTRACT FROM AUTHOR]

This work focuses on the effect of the interval between two shocks on the ejecta formation from the grooved aluminum (Al1100) surface by using smoothed particle hydrodynamics numerical simulation. Two unsupported shocks are obtained by the plate-impact between sample and two flyers at interval, with a peak pressure of approximately 30 GPa for each shock. When the shock interval varies from 2.11 to 7.67 times the groove depth, the bubble velocity reduces to a constant, and the micro jetting factor RJ from spike to bubble exhibits a non-monotonic change that decreases initially and then increases. At a shock interval of 3.6 times the groove depth, micro jetting factor RJ from spike to bubble reaches its minimum value of approximately 0.6. While, the micro jetting factor RF from spike to free surface decreases linearly at first, and stabilizes around 0.25 once the shock interval surpasses 4.18 times the groove depth. When the shock interval is less than 4.18 times the groove depth, the unloading wave generated by the breakout of the first shock wave is superimpose with the unloading part of the second shock wave to form a large tensile area.

This paper introduces an algorithm to tackle the boundary condition (BC) problem, which has long persisted in the numerical and computational treatment of smoothed particle hydrodynamics (SPH). Central to the BC problem is a need for an effective method to reconcile a numerical representation of particles with 2D or 3D geometry. We describe and evaluate an algorithmic solution—boundary SPH (BSPH)—drawn from a novel twist on the mesh-based boundary method, allowing SPH particles to interact (directly and implicitly) with either convex or concave 3D meshes. The method draws inspiration from existing works in graphics, particularly discrete signed distance fields, to determine whether particles are intersecting or submerged with mesh triangles. We evaluate the efficacy of BSPH through application to several simulation environments of varying mesh complexity, showing practical real-time implementation in Unity3D and its high-level shader language (HLSL), which we test in the parallelization of particle operations. To examine robustness, we portray slip and no-slip conditions in simulation, and we separately evaluate convex and concave meshes. To demonstrate empirical utility, we show pressure gradients as measured in simulated still water tank implementations of hydrodynamics. Our results identify that BSPH, despite producing irregular pressure values among particles close to the boundary manifolds of the meshes, successfully prevents particles from intersecting or submerging into the boundary manifold. Average FPS calculations for each simulation scenario show that the mesh boundary method can still be used effectively with simple simulation scenarios. We additionally point the reader to future works that could investigate the effect of simulation parameters and scene complexity on simulation performance, resolve abnormal pressure values along the mesh boundary, and test the method's robustness on a wider variety of simulation environments. [ABSTRACT FROM AUTHOR]

Smoothed particle hydrodynamics (SPH) method is widely accepted as a flexible numerical treatment for surface boundaries and interactions. High-resolution simulations of hydrodynamic events require high-performance computing (HPC). There is a need for an SPH code that runs efficiently on modern supercomputers involving accelerators such as NVIDIA or AMD graphics processing units. In this work, we applied half-precision, which is widely used in artificial intelligence, to the SPH method. However, improving HPC performance at such low-order precisions is a challenge. An as-is implementation with half-precision will have lower computational cost than that of float/double precision simulations, but also worsens the simulation accuracy. We propose a scaling and shifting method that maintains the simulation accuracy near the level of float/double precision. By examining the impact of half-precision on the simulation accuracy and time-to-solution, we demonstrated that the use of half-precision can improve the computational performance of SPH simulations for scientific purposes without sacrificing the accuracy. In addition, we demonstrated that the efficiency of half-precision depends on the architecture used. [ABSTRACT FROM AUTHOR]