Smoothed Particle Hydrodynamics Method Research Articles

Mechanism of Cathode Microcrater Formation under Vacuum Arc Based on Smoothed Particle Hydrodynamics Method

Mechanism of Cathode Microcrater Formation under Vacuum Arc Based on Smoothed Particle Hydrodynamics Method

Numerical modeling of cutting force and chip formation during water Jet Assisted Machining of Ti17 based on SPH/FEM method

In this paper, we conduct a numerical simulation of a water jet-assisted machining process for a titanium alloy Ti17, with a focus on addressing the Fluid-Structure Interaction (FSI) problem arising during lubricated machining. The proposed coupling strategy employs the Smoothed Particle Hydrodynamics (SPH) free mesh method, coupled with an ordinary Lagrangian mesh. The SPH method is utilized to model the water jet, while the Lagrangian Finite Element Method (FEM) is employed to represent the workpiece and the tool. The hydrodynamic behavior of water is captured using the linear Huguenot form of the Mie-Greisen equation of state. Additionally, the Johnson-Cook constitutive law is applied to describe the thermoviscoplastic behavior of the titanium alloy. It is essential to note that thermal and mechanical effects were decoupled in this study. The investigation focuses on cutting force and chip morphology under two distinct cutting regimes: Dry Machining (DM) and Water Jet Assisted Machining, specifically with conventional lubrication (CL). The numerical simulations are compared with experimental results found in the literature, with an emphasis on cutting force and chip morphology. The obtained simulation results exhibit a favorable correlation with the experimental data. All numerical simulations were conducted using ABAQUS version 6.14.

Application of Smoothed Particle Hydrodynamics Method for Tsunami Force Modeling on Building with Openings

Smoothed Particle Hydrodynamics (SPH) serves as a numerical technique extensively employed for simulating free surface flow. The computational intricacy of the SPH method arises from the numerous computations of a particle's properties, derived from interactions with surrounding particles. To address this complexity, experts developed DualSPHysics. This study employs the SPH method, specifically the DualSPHysics application, for tsunami modeling. To accurately represent tsunami characteristics, precise numerical parameters are essential for numerical modeling. This research provides valuable insights into optimizing numerical parameters for accurate SPH simulations. Therefore, the research aims to identify the exact values of crucial parameters in DualSPHysics model. Validation of numerical calculations involves comparing the tsunami forces, as simulated by DualSPHysics, with secondary data obtained from physical experiments results. The findings highlight the significance of particle size (dp) as a crucial numerical parameter in DualSPHysics modeling. A smaller particle size contributes to model’s accuracy. The determination of the particle size must account for model’s shortest characteristic (s). According to simulations those have been carried out, it is recommended to set the maximum limit value of dp/s at 1/3.67 to achieve precise calculation. Furthermore, the DualSPHysics simulation demonstrates a reduction in force due to the opening configuration (n).

Simulation of Plastic Deformation Failure of Tillage Tools Based on the Smoothed Particle Hydrodynamics Method

The problems of large deformations, failures, and fractures that agricultural tillage tools may encounter during the cultivation process has long been a concern in the field of agricultural machinery design and manufacturing. It is important to establish a more accurate numerical model to effectively predict tools’ plastic deformation failures and ductile fracture failures. This research develops a numerical model for predicting the plastic deformation failure and ductile fracture failure of agricultural tillage tools using the smoothed particle hydrodynamics (SPH) method and the Johnson–Cook constitutive model. The model uses the Drucker–Prager criterion to describe the elastic–plastic constitutive behavior of the soil, the von Mises criterion to describe the Johnson–Cook constitutive model of the tool, and the coupling condition with the Lennard-Jones repulsive force to describe the interaction between the tool and soil. The numerical results show that the proposed model can effectively simulate the interaction between the tool and soil, as well as the tool’s plastic deformation failure and ductile fracture failure during the agricultural cultivation process. It can also predict the variation trend of the cutting force of the tool. This helps to provide a new approach for the numerical simulation of such problems.

Optimizing rock breaking performance: The influence of chamfer on polycrystalline diamond compact (PDC) cutters

Research on the rock-breaking performance of the Polycrystalline Diamond Compact (PDC) cutter has primarily focused on sharp cutters, often overlooking the influence of chamfer. Notably, the design of chamfer parameters has been largely unreported. In this study, we established a theoretical model of cutting force that takes chamfer into account. We analysed the primary and secondary relationships of four factors – back rake angle, depth of cut, chamfer angle, and chamfer length – on the force of the PDC cutter. This was done through a pseudo-level orthogonal level test. A numerical simulation, based on the Smooth Particle Hydrodynamic (SPH) method, was conducted to analyse the rock-breaking force and stress distribution characteristics of PDC cutters with different chamfer angles. Combined with a drop hammer impact test, we provided an optimized design of chamfer parameters. Our findings revealed that while the chamfer had a relatively minor influence on the force of the PDC cutter, it contributed to the optimal distribution of stress on the PDC cutter. This effectively protected the cutting edge and prevented early cracks and spalls of the cutter. When the chamfer angle was less than or equal to the back rake angle, the resultant force of the PDC cutter increased with the increase of the chamfer angle. However, when the chamfer angle was greater than the back rake angle, the resultant force of the PDC cutter first increased and then slightly decreased with the increase of the chamfer angle. Additionally, the resultant force of the PDC cutter increased approximately linearly with the increase of chamfer length. When the chamfer angle of the PDC cutter was between 30° and 45°, the fluctuation of the cutting force was relatively smooth, the rock-breaking process was stable, and the cutter’s impact resistance energy was relatively higher. These findings will provide valuable guidelines for the design of chamfered PDC cutters.

Coupling of smoothed particle hydrodynamics and finite volume method for electrohydrodynamic droplet deformation simulation

In the numerical simulation of droplet electrohydrodynamic deformation, the grid-based method is difficult to handle the large topological deformation of the droplet interface, while the meshless method is challenging in the enforcement of boundary conditions. Therefore, a coupling method of the smoothed particle hydrodynamics (SPH) method and the finite volume method (FVM) is developed in this paper. In the present coupling method, the SPH method is used to solve the governing equations of the two-phase flow, while the FVM is used to solve the governing equations of the electric field. The realization of the coupling method is based on the information transfer between particles and grids. In order to accurately transfer the electric field force of interface grid nodes to SPH particles, a particle splitting interpolation method is developed. The influences of electrical capillary number, electrical conductivity ratio, and permittivity ratio on droplet deformation are studied. The simulation results are in good agreement with the theoretical predictions, and the coupling method can obtain more accurate numerical results than the pure SPH method. The coupling method can provide a reliable way to investigate complex electrohydrodynamic problems.

Numerical simulation of safety injection and natural circulation in two containers by smoothed particle hydrodynamics on the effects of filling levels and thermal diffusivities

Natural circulation is an important process in reactor thermal-hydraulics study. This process is simulated by Smoothed particle hydrodynamics method for a modeled system of circulation. A new kernel function of (−1, 5) power components has been proposed here and validated by the dam-break case. The modeled circulation system is composed of two containers of different heights. Three filling levels (Case A) and four thermal diffusivities (Case B) have been utilized to analyze their effects. Six vortex-criteria have been utilized to visualize the representative vortical motion of fluids inside the containers. Circulations of velocity and velocity–temperature, heat transfer amount, mean temperature and mean material derivative have been defined here to quantify the feature of natural circulations for the two cases. The results show that the filling levels affect mainly the process of setup, rather than the steady level of natural circulation. A high filling level has a considerable larger amount of heat transfer between the hot and cool fluids. The thermal diffusivity does not affect the process of the circulation level, whereas it has great effects on the mean as well material derivative of the temperature of fluids. For example, comparing the mean temperature of the fluid at the thermal diffusivity α = 0.02 to that at α = 2.79 (in Case B at t=600 s), the mean temperature of cool fluids is about 15 °C lower at α=0.02 than that at α=2.79, whereas the mean temperature of hot fluids is about 7 °C higher at α=0.02 than that at α=2.79. In addition, the difference in the initial temperature of fluids and the difference in heights between two containers affect the natural circulation levels.

Calibration of an expeditious terramechanics model using a higher‐fidelity model, Bayesian inference, and a virtual bevameter test

AbstractThe soil contact model (SCM) is widely used in practice for off‐road wheeled vehicle mobility studies when simulation speed is important and highly accurate results are not a main concern. In practice, the SCM parameters are obtained via a bevameter test, which requires a complex apparatus and experimental procedure. Here, we advance the idea of running a virtual bevameter test using a high‐fidelity terramechanics simulation. The latter employs the “continuous representation model” (CRM), which regards the deformable terrain as an elasto‐plastic continuum that is spatially discretized using the smoothed particle hydrodynamics method. The approach embraced is as follows: a virtual bevameter test is run in simulation using CRM terrain to generate “ground truth” data; in a Bayesian framework, this data is subsequently used to calibrate the SCM terrain. We show that (i) the resulting SCM terrain, while leading to fast terramechanics simulations, serves as a good proxy for the more complex CRM terrain; and (ii) the SCM‐over‐CRM simulation speedup is roughly one order of magnitude. These conclusions are reached in conjunction with two tests: a single wheel test, and a full rover simulation. The SCM and CRM simulations are run in the open‐source software Chrono. The calibration is performed using PyMC, which is a Python package that interactively communicates with Chrono to calibrate SCM. The models and scripts used in this contribution are available as open source for unfettered use and distribution in a public repository.

A SPH-FVM coupling method based on triangular mesh for the simulation of two-phase flows

Combining the advantages of the smoothed particle hydrodynamics method (SPH) in interface tracking and the finite volume method (FVM) in computational conservation, the SPH-FVM coupling method for interface flow simulation has been developed in recent years. The existing SPH-FVM coupling methods are based on the structured mesh which are difficult for the simulation of interfacial flows in irregular flow regions. In order to improve the applicability of SPH-FVM coupling method in the simulation of two-phase interfacial flow in irregular flow regions, a SPH-FVM coupling method based on triangular mesh is developed in this paper. The bidirectional transfer of information between the particles and the triangular grids is implemented in this study. A self-programming of SPH-FVM coupling method based on triangular mesh is realized. Some typical two-phase interfacial flows in regular and irregular flow regions are applied to verify the effectiveness and accuracy of the developed SPH-FVM coupling method. Results indicate that the SPH-FVM coupling method based on triangular mesh developed in this paper has good performance for the simulation of two-phase interfacial flow. Therefore, the SPH-FVM coupling method based on triangular mesh can be used as an optional method for the simulation of two-phase interfacial flow in irregular flow regions.

Ultrasonic-Vibration-Assisted Waterjet Drilling of [0/45/-45/90]2s Carbon-Fiber-Reinforced Polymer Laminates.

The pure waterjet (WJ) drilling process of carbon-fiber-reinforced polymer (CFRP) laminates causes damage, such as tears and delamination, leading to poor-quality hole-wall. Ultrasonic-vibration-assisted technology can improve the quality of hole walls and repair such damage, particularly the delamination of CFRP laminates. In this study, we conducted a numerical and experimental investigation of a high-pressure pure WJ drilling process of CFRP laminates performed using ultrasonic vibration to improve the delamination phenomena of the pure WJ drilling process. An explicit dynamic model using the smoothed particle hydrodynamics method was employed to simulate the ultrasonic-vibration-assisted WJ drilling of CFRP laminates and ascertain the optimal drilling performance. Thereafter, WJ drilling experiments were conducted to verify the numerical simulation. The results illustrate that the employment of ultrasonic vibration significantly increased the material removal rate by approximately 20%. Moreover, the water-wedging action that induces the propagation of delamination was weakened with an increase in the amplitude of the ultrasonic vibration. The hole-wall quality was optimal with the following drilling parameters: amplitude, 10 μm; frequency, 20 kHz; and WJ velocity, 900 m/s. The delamination zone length was only 0.19 mm and was reduced by 85.6% compared with the values obtained using non-assisted WJ drilling.

Numerical investigation of vehicle wading based on an entirely particle-based three-dimensional SPH model

Vehicle wading problems have received increasing attention from the automotive community in recent years because of the prosperous developments of electric vehicles, for which the performance of water tightness can be more important than conventional fuel vehicles. This paper presents an attempt to simulate vehicle wading problems based on an entirely meshless framework by using Smoothed Particle Hydrodynamics (SPH). First of all, an easy-to-implement but effective strategy is proposed to prevent the penetration between fluid particles and a wall boundary modeled by a set of solid particles when the distribution quality of the solid particles is poor. Subsequently, a comparative study is conducted to assess the feasibility and applicability of the SPH and Finite Volume (FV) methods in solving vehicle wading problems. Furthermore, the wading dynamics of a vehicle passing a puddle under different combinations of wading speeds and accumulating water depths is also investigated and discussed in detail by using the SPH method. It is suggested that the SPH method can be regarded as a potential candidate for solving vehicle wading problems, especially for those situations where the free-surface evolution during the wading process is particularly concerning.

Extended Applications of the δ-SPH Model for the Numerical Study of Fluid–Soil Interactions

The fluid–soil interactions play a significant role in coastal and ocean engineering applications. However, there are still some complex mechanical problems with large deformations of water–soil interfaces to be solved. As a particle-based Lagrangian method, Smoothed Particle Hydrodynamics (SPH) is good at solving multiphase problems with large deformations of boundaries or interfaces. Therefore, in this work, the [Formula: see text]-SPH method is extended for the simulation of fluid–soil interacting problems. First, based on the weakly compressible assumption, the water is modeled as a viscous fluid while the soil is considered as a material with elastic–perfectly plastic behaviors. The [Formula: see text]-SPH method is implemented on the two phases separately, while the stress diffusive term only acts on the soil. The seepage force is introduced to model the interaction between two phases. After that, several numerical test cases with small to large interface deformations are presented. It is shown that the fluid–soil interacting model based on the [Formula: see text]-SPH model gives satisfying results compared with experimental data. Finally, the model is further extended for the simulation of vertical or oblique water jet scouring problems which demonstrates the potential applications of the SPH model for complex engineering problems.

A numerical methodology for estimating site-specific cascading earthquake and tsunami dynamic loading on critical infrastructure

A numerical methodology for deriving cascading earthquake and tsunami loading patterns for use in critical infrastructure design is proposed. Earthquake source parameters are first used to generate synthetic ground motion acceleration time series at the site of a critical infrastructure using an open-source stochastic extended finite-source simulation algorithm. Using the same earthquake source information, the tsunami phases of generation, propagation, and inundation are modeled using a coupling approach for determining tsunami wave forces. The coupling approach combines (1) a code based on non-linear shallow water equations solved by the Finite Volume method, which is used to capture the tsunami flow characteristics from generation through the inundation phase until relatively close to the structure, coupled with (2) an open-source computational fluid simulation code, which relies on solving the Navier–Stokes equations using the Smoothed Particle Hydrodynamics method. An appendix presents the validation of the numerical methodology through correlation of the numerical simulations with field data recorded during the 2011 Japan Earthquake and Tsunami. The methodology is then employed to characterize the ground shaking and tsunami loading patterns at the site of the container terminal of the Sines deep-water seaport in Portugal, when subjected to the historic 1755 Great Lisbon Earthquake and Tsunami plausible scenarios. For the site, the generated ground motion acceleration time series show peak accelerations exceeding Eurocode 8 design values. Tsunami flow depths and velocities were computed in horizontal and vertical directions and could be used in the assessment of the existing infrastructure or the design of the future expansion of the port.

Numerical simulation of dry laser derusting process based on SPH method

Laser cleaning is an efficient, environmental-friendly, and non-contact surface treatment technology. Laser radiation and heating cause the surface material to heat up and gasify, separating it from the substrate. Traditional mesh-based numerical methods are difficult to effectively simulate the evolution of erosion crater and the splashing phenomenon. In this study, a meshfree method, the smoothed particle hydrodynamics (SPH) method, is used to establish the numerical model of the interaction between the laser beam and the targeted material and to investigate the removal process of the rust layer under different laser operating conditions. In consideration of the coupling effect of laser absorption, heat transfer, and material phase change, the SPH modeling procedure and corresponding numerical scheme for heat transfer and heat-absorption-induced phase change are introduced. Additionally, a surface particle detection algorithm and surface normal vector calculation method are proposed to accurately compute the complex surface geometry of the erosion crater, which realizes the dynamic coupling of laser-energy absorption and laser-beam direction. The established SPH model is then used to simulate the temperature distribution of the rust layer under the action of a laser beam, and the influence of laser energy, beam overlap rate, and beam direction on the removal efficiency is analyzed. This study applies the meshfree SPH method to the study of laser rust removal process, verifies the accuracy of the surface detection algorithm, captures the spatter behavior of material particles after phase change, and reflects the advantages of the meshfree method in solving such problems.

Two-Dimensional Simulation of Dam Break with Partial Damage Condition using Ansys Software

The issue of dam failure has been a key contributor to massive catastrophes, as well as economic and physical destruction. Nevertheless, the effectiveness and accuracy of the simulation of a dam break model are still under debate. In this study, a simulation of a 2D model of the dam breaking half-filled water tank was carried out using Ansys software to evaluate the deformation and water pressure of dam break flow. Four sensors were installed to examine the changes in pressure of the water deformation. Deformation of water at a certain time of the dam break simulation and the pressure of water inside were analyzed and compared with the experimental result, which has been reported by Lobovský. Validation and verification of hydrostatic tests have been found to be in agreement with the current model simulation. An extensive set of data for the simulation is given access as supplementary materials for the direct result of the recent initiative. The results show that by excluding minor differences in wave shape and duration of water movement, the deformation of water exemplifies the same behavior as the experimental results. For experimental data, the non-dimensional time of the dam break event is ranged within 0 to 7.14828 ms while the pressure of water flow is within 0 to 3.0441 Pa. As for simulation results, the non-dimensional time of the dam break event is ranged within 0 to 202 ms whereas the pressure of water flow is within 0 to 0.54124 Pa. Thus, to strengthen the quality numerical model, future work should emphasize the initiative to incorporate the Smooth Particle Hydrodynamics (SPH) method with the goal of improving computational validity and efficiency.

A discontinuous smooth particle hydrodynamics method for modeling deformation and failure processes of fractured rocks

A discontinuous smoothed particle hydrodynamics (DSPH) method considering block contacts is originally developed to model the cracking, frictional slip and large deformation in rock masses, and is verified by theoretical, numerical and/or experimental results. In the DSPH method, cracking is realized by breaking the virtual bonds via a pseudo-spring method based on Mohr–Coulomb failure criteria. The damaged particles are instantaneously replaced by discontinuous particles and the contact bond between the original and discontinuous particles is formed to simulate the frictional slip and separation/contraction between fracture surfaces based on the block contact algorithm. The motion of rock blocks and the contact force of discontinuous particles are determined following Newton's second law. The results indicate that the DSPH method precisely captures the cracking, contact formation and complete failure across six numerical benchmark tests. This single smoothed particle hydrodynamics (SPH) framework could significantly improve computational efficiency and is potentially applicable to broad multi-physical rock engineering problems of different scales.

Fluid–structure interaction modeling of bi-leaflet mechanical heart valves using smoothed particle hydrodynamics

Heart valves are essential for maintaining unidirectional blood flow, and their failure can severely affect cardiac functions. The use of artificial heart valves as replacement has proven to be a reliable and effective solution. Computational fluid dynamics has emerged as a powerful numerical tool for investigating the design, performance, and malfunctioning of mechanical heart valves without the need for invasive procedures. In this study, we employed smoothed particle hydrodynamics (SPH) in an open-source code “DualSPHysics,” to study the hemodynamics of a bi-leaflet mechanical heart valve (BMHV). The proposed SPH method was validated against the traditional finite volume method and experimental data, highlighting its suitability for simulating the heart valve function. The Lagrangian description of motion in SPH is particularly advantageous for fluid–structure interaction (FSI), making it well-suited for accurately modeling the heart valve dynamics. Furthermore, the SPH/FSI technique was applied to investigate the hemodynamic abnormalities associated with BMHV dysfunction. This work represents the first attempt to use SPH to model flow through a realistic BMHV by incorporating FSI. The normal and altered flow behavior and the movement dynamics of the BMHV under various blockage scenarios have also been investigated along with the potential risks of the blocked mechanical valve. The findings demonstrate that this SPH/FSI approach provides a unique, effective, and valuable tool for accurately capturing the transient hemodynamic behavior of bi-leaflet heart valves and its versatility enables the application to more complex patient-specific issues related to cardiovascular diseases.

Three-dimensional numerical study of two drops impacting on a heated solid surface by smoothed particle hydrodynamics

This paper presents a numerical study of a pair of water drops simultaneously and non-simultaneously impacting on a heated surface using smoothed particle hydrodynamics (SPH). The present SPH method is validated qualitatively and quantitively with available experiment results for the impact of single, simultaneous, and non-simultaneous drops on the solid surface. Numerical simulations are performed at the Weber number in the range of 20–117, surface temperature in the range of 25–250 °C, and pressure in the range of 1–20 bar. In the simulations, the coalescence, breakup, and evaporation of the drops are considered. After the collision of the two drops, the hydrodynamic behavior of the uprising sheet height and spreading areas are investigated by considering the horizontal and vertical distances between the two drops, Weber number, surface temperature, and elevated pressure. The numerical results indicate that the Weber number and horizontal distance significantly influence the height of the rising sheet and the spreading area. Conversely, the vertical spacing does not affect the rising sheet height or spreading area. The drop rebound height increases with the wall temperature in the film boiling regime for high boiling point liquids at atmospheric pressure. The effect of ambient pressure on drop rebound height is investigated for simultaneous and non-simultaneous impacts. According to the numerical results, the pressure increase causes a decrease in droplet rebound height.

SPH Simulation of the Interaction between Freak Waves and Bottom-Fixed Structures

In this paper, the Smoothed Particle Hydrodynamics (SPH) method is used in a C# environment to simulate the interaction between freak waves and bottom-fixed structures by establishing a fluid dynamics model. Paraview software 5.10.1 was used to analyze and visualize the simulation results. In order to simulate wave propagation accurately, the reliability of the model was verified by comparing experimental and simulated data. A two-dimensional numerical wave flume was established based on the SPH method, a conservative Riemann solver was introduced, a repulsive boundary condition was adopted, and a slope was used to eliminate wave reflection. Bottom-fixed structures of different heights and lengths, as well as different wave conditions, were selected to numerically simulate the interaction between freak waves and bottom-fixed structures. The results show that the height of bottom-fixed structures and wave conditions have a significant effect on hindering the propagation of rogue waves, while the length has little effect on the propagation of deformed waves. When the amplitude of the wave remains constant, both the period andthe duration of the deformed wave are longer. This research is of certain significance for the prediction of freak waves in marine engineering and the application and promotion of SPH methods.

Implicit Surface Tension for SPH Fluid Simulation

The numerical simulation of surface tension is an active area of research in many different fields of application and has been attempted using a wide range of methods. Our contribution is the derivation and implementation of an implicit cohesion force based approach for the simulation of surface tension effects using the Smoothed Particle Hydrodynamics (SPH) method. We define a continuous formulation inspired by the properties of surface tension at the molecular scale which is spatially discretized using SPH. An adapted variant of the linearized backward Euler method is used for time discretization, which we also strongly couple with an implicit viscosity model. Finally, we extend our formulation with adhesion forces for interfaces with rigid objects. Existing SPH approaches for surface tension in computer graphics are mostly based on explicit time integration, thereby lacking in stability for challenging settings. We compare our implicit surface tension method to these approaches and further evaluate our model on a wider variety of complex scenarios, showcasing its efficacy and versatility. Among others, these include but are not limited to simulations of a water crown, a dripping faucet, and a droplet toy.