A Comparison of Smoothed Particle Hydrodynamics (SPH) and Coupled SPH-FEM Methods for Modeling Machining

2020 ◽  
Author(s):  
Nishant Ojal ◽  
Harish P. Cherukuri ◽  
Tony L. Schmitz ◽  
Adam W. Jaycox
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Solid Mechanics ◽  
Large Deformations ◽  
Computational Time ◽  
Depth Of Cut ◽  
Fe Model ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle

Abstract Smoothed Particle Hydrodynamics (SPH), a particle-based, meshless method originally developed for modeling astrophysical problems, is being increasingly used for modeling fluid mechanics and solid mechanics problems. Due to its advantages over grid-based methods in the handling of large deformations and crack formation, the method is increasingly being applied to model material removal processes. However, SPH method is computationally expensive. One way to reduce the computational time is to partition the domain into two parts where, the SPH method is used in one segment undergoing large deformations and material separation and in the second segment, the conventional finite element (FE) mesh is used. In this work, the accuracy of this SPH-FEM approach is investigated in the context of orthogonal cutting. The high deformation zone (where chips form and curl) is meshed with the SPH method, while the rest of the workpiece is modeled using the FE method. At the interface, SPH particles are coupled with FE mesh for smooth transfer of stress and displacement. The boundary conditions are applied to tool and FE zone of the workpiece. For comparison purposes, a fully-SPH model (workpiece fully discretized by SPH) is also developed. This is followed by a comparison of the results from the coupled SPH-FE model with the SPH model. A comparison of the chip profile, the cutting force, the von Mises stress and the damage parameter show that the coupled SPH-FE model reproduces the SPH model results accurately. However, the SPH-FE model takes almost 40% less time to run, a significant gain over the SPH model. Similar reduction in computation time is observed for in a micro-cutting application (depth of cut of 300 nm). Based on these results, it is concluded that coupling SPH with FEM in machining models decreases simulation time significantly while still producing accurate results. This observation suggests that three-dimensional machining problems can be modeled using the combined SPH-FEM approach without sacrificing accuracies.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

A STABLE LARGE DEFORMATION CORRECTED SPH METHOD BASED ON STABILIZED CONFORMING NODAL INTEGRATION AND LAGRANGIAN KERNELS

2012 ◽  
Vol 09 (04) ◽  
pp. 1250057
Author(s):  
S. WANG
Keyword(s):  
Large Deformation ◽  
Smoothed Particle Hydrodynamics ◽  
Solid Mechanics ◽  
Particle Methods ◽  
Sph Method ◽  
Nodal Integration ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Meshless Approximation ◽  
Complex Phenomena

In this paper, we propose a Galerkin-based smoothed particle hydrodynamics (SPH) formulation with moving least-squares meshless approximation, applied to solid mechanics and large deformation. Our method is truly meshless and based on Lagrangian kernel formulation and stabilized nodal integration. The performance of the methodology proposed is tested through various simulations, demonstrating the attractive ability of particle methods to handle severe distortions and complex phenomena.

MODELLING URBAN COASTAL FLOODING THROUGH 2-D ARRAY OF BUILDINGS USING SMOOTHED PARTICLE HYDRODYNAMICS

2017 ◽  
pp. 37
Author(s):  
Sohaib Rashid Sulaiman Alahmed ◽  
Qingping Zou
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Complex Flow ◽  
Sph Method ◽  
Flooding Event ◽  
Particle Hydrodynamics ◽  
Flow Features ◽  
Sph Model ◽  
Smoothed Particle ◽  
Flood Characteristics ◽  
Water Elevation

A Smoothed Particle Hydrodynamics (SPH) method is used to investigate the flood characteristics occurring in an idealized city with two different building layouts: aligned layout and 22.5o skewed layout with respect to the direction of the incoming flow. The model results show that the water elevation is higher for the skewed city layout than that for the aligned city layout. The force due to the flood impact on the majority of buildings tend to be higher for the former than that for the latter. The complex flow features including a hydraulic jump during the flooding event are well captured by the SPH model.

scholarly journals Dual-Support Smoothed Particle Hydrodynamics for Elastic Mechanics

2017 ◽  
Vol 14 (04) ◽  
pp. 1750039 ◽  
Author(s):  
Zili Dai ◽  
Huilong Ren ◽  
Xiaoying Zhuang ◽  
Timon Rabczuk
Keyword(s):  
Linear Transformation ◽  
Smoothed Particle Hydrodynamics ◽  
Three Dimensions ◽  
Benchmark Problems ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Support Domain ◽  
Elastic Mechanics

In the standard smoothed particle hydrodynamics (SPH) method, the interaction between two particles might be not pairwise when the support domain varies, which can result in a reduction of accuracy. To deal with this problem, a modified SPH approach is presented in this paper. First of all, a Lagrangian kernel is introduced to eliminate spurious distortions of the domain of material stability, and the gradient is corrected by a linear transformation so that linear completeness is satisfied. Then, concepts of support and dual-support are defined to deal with the unbalanced interactions between the particles with different support domains. Several benchmark problems in one, two and three dimensions are tested to verify the accuracy of the modified SPH model and highlight its advantages over the standard SPH method through comparisons.

Numerical Simulation of the Protection System of Explosive Reaction Armor

2013 ◽  
Vol 760-762 ◽  
pp. 2188-2193
Author(s):  
Wen Hua Chu ◽  
Aman Zhang ◽  
Xiong Liang Yao
Keyword(s):  
Numerical Simulation ◽  
Smoothed Particle Hydrodynamics ◽  
Approximate Formula ◽  
Engineering Application ◽  
Extreme Conditions ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Explosive Reaction

There are some extreme conditions in the process of metallic jet penetrating the explosive reaction armor (ERA), such as high instantaneity, large deformation, et al. Based on the smoothed particle hydrodynamics (SPH) method, the generalized density approximate formula is proposed and the Held criterion is introduced. Then the numerical SPH model of metallic jet penetrating the explosive reaction armor is built to study its protection mechanics. The calculation result meets well with the theoretical value. The influences of some parameters, such as thickness of plate and attacking angle, on the protecting effect of explosive reaction armor are analyzed, aiming at providing references for the related engineering application.

scholarly journals Numerical simulation of droplet impinging icing process on a low-temperature wall with smoothed particle hydrodynamics (SPH) method

2021 ◽  
pp. 258-258
Author(s):  
Bowen Zhang ◽  
Xiaojing Ma ◽  
Xinchao Zhou ◽  
Guangyuan Li
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Smoothed Particle Hydrodynamics ◽  
Transition Process ◽  
Sph Method ◽  
Droplet Impingement ◽  
Phase Transition Process ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle

Based on the basic principles and improved algorithms of the smoothed particle hydrodynamics (SPH) method, a corresponding surface tension model and latent heat model are proposed for the heat exchange phase transition problem of droplets impinging on a low-temperature wall surface. This research establishes a novel SPH model of the impinging wall of droplets accompanied by the phase transition process. This work also includes simulations covering the spreading flow and phase transition process of droplets under different impingement regimes. Moreover, the icing patterns of the droplet impingement spreading process are provided and a comparative analysis with related experimental results. The improved SPH model is verified by experiments and its ability to solve droplet impingement icing problems.

Geometrically nonlinear analysis of two-dimensional structures using an improved smoothed particle hydrodynamics method

2015 ◽  
Vol 32 (3) ◽  
pp. 779-805 ◽  
Author(s):  
Jun Lin ◽  
Hakim Naceur ◽  
Daniel Coutellier ◽  
Abdel Laksimi
Keyword(s):  
Nonlinear Analysis ◽  
Smoothed Particle Hydrodynamics ◽  
Time Integration ◽  
Geometrically Nonlinear ◽  
Sph Method ◽  
Geometrically Nonlinear Analysis ◽  
Content Type ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle

Purpose – The purpose of this paper is to present an efficient smoothed particle hydrodynamics (SPH) method particularly adapted for the geometrically nonlinear analysis of structures. Design/methodology/approach – In order to resolve the inconsistency phenomenon which systematically occurs in the standard SPH method at the domain’s boundaries of the studied structure, the classical kernel function and its spatial derivatives were modified by the use of Taylor series expansion. The well-known tensile instabilities inherent to the Eulerian SPH formulation were attenuated by the use of the Total Lagrangian Formulation (TLF). Findings – In order to demonstrate the effectiveness of the present improved SPH method, several numerical applications involving geometrically nonlinear behaviors were carried out using the explicit dynamics scheme for the time integration of the PDEs. Comparisons of the obtained results using the present SPH model with analytical reference solutions and with those obtained using ABAQUS finite element (FE) commercial software, show its good accuracy and robustness. Practical implications – An additional application including a multilayered composite structure and involving buckling and delamination was investigated using the present improved SPH model and the results are compared to the FE results, they confirmed both the efficiency and the accuracy of the proposed method. Originality/value – An efficient 2D-continuum SPH model for the geometrically nonlinear analysis of thin and thick structures is proposed. Contrarily to the classical SPH approaches, here the constitutive material relations are used to link naturally the stresses and strains. The Total Lagrangian approach is investigated to alleviate the tensile instabilities problem, allowing at the same time to avoid the updating procedure of the neighboring particles search and therefore reducing CPU usage. The proposed approach is valid for isotropic and multilayered composites structures undergoing large transformations. CPU time savings and better results with the new 2D-continuum SPH formulation compared to the classical continuum SPH. The explicit dynamic scheme was used for time integration allowing a fast resolution algorithm even for highly nonlinear problems.

Hydrodynamics Analysis Based on Improved VBF SPH Model

2013 ◽  
Vol 443 ◽  
pp. 145-149
Author(s):  
Da Ming Li ◽  
Zhi Chao Wang ◽  
Hao Mei Xu ◽  
Hao Luo ◽  
Yang Yang Li ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Visual Basic ◽  
Dynamic Link Library ◽  
Sph Method ◽  
Mixed Language ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Model Efficiency ◽  
Flood Flow

To improve the application of Smoothed Particle Hydrodynamics (SPH) method, a new Visual Basic-Fortran (VBF) SPH model with the improvements on efficiency and visualizable interface is presented. The VBF SPH model is based on mixed language programming (MLP) method that not only improved SPH model’s efficiency, but also created the interface functions to control and observe the whole simulation. İts general structrue is to compiling the Fortran computing subroutines into Dynamic Link Library (DLL) files and these files will be called by Visual Basic (VB) programs during the calculation. Besides that an improved link-list algorithm, is described detailedly. This algorithm improves the model’s searching efficiency by reducing the number of searching cells. Two classical problems, Flood flow over Dam and Droplet-Impact, are chosen to analyze the VBF SPH model efficiency and distinguish the improvements’ effect. Both of problems are simulated respectively by VBF SPH model and VB model. According to first simulation VBF SPH model is more than 8 times faster than the VB model. And the second simulation refers that the MLP method increased about 7 times efficiency while the improved link-list algorithm increased more than 1 time.

scholarly journals SPH Modelling of Sea-ice Pack Dynamics

2017 ◽  
Vol 64 (2) ◽  
pp. 115-137 ◽  
Author(s):  
Ryszard Staroszczyk
Keyword(s):  
Sea Ice ◽  
Smoothed Particle Hydrodynamics ◽  
Horizontal Plane ◽  
Large Deformations ◽  
Ice Thickness ◽  
Water Currents ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Ice Pack

AbstractThe paper is concerned with the problem of sea-ice pack motion and deformation under the action of wind and water currents. Differential equations describing the dynamics of ice, with its very distinct mateFfigrial responses in converging and diverging flows, express the mass and linear momentum balances on the horizontal plane (the free surface of the ocean). These equations are solved by the fully Lagrangian method of smoothed particle hydrodynamics (SPH). Assuming that the ice behaviour can be approximated by a non-linearly viscous rheology, the proposed SPH model has been used to simulate the evolution of a sea-ice pack driven by wind drag stresses. The results of numerical simulations illustrate the evolution of an ice pack, including variations in ice thickness and ice area fraction in space and time. The effects of different initial ice pack configurations and of different conditions assumed at the coast-ice interface are examined. In particular, the SPH model is applied to a pack flow driven by a vortex wind to demonstrate how well the Lagrangian formulation can capture large deformations and displacements of sea ice.

scholarly journals Progress in the Smoothed Particle Hydrodynamics Method to Simulate and Post-process Numerical Simulations of Annular Airblast Atomizers

2020 ◽  
Vol 105 (4) ◽  
pp. 1119-1147
Author(s):  
G. Chaussonnet ◽  
T. Dauch ◽  
M. Keller ◽  
M. Okraschevski ◽  
C. Ates ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Flux Ratio ◽  
Liquid Sheet ◽  
Sph Method ◽  
Post Process ◽  
Finite Time Lyapunov Exponent ◽  
Fragmentation Spectrum ◽  
Particle Hydrodynamics ◽  
Primary Breakup ◽  
Smoothed Particle

AbstractThis paper illustrates recent progresses in the development of the smoothed particle hydrodynamics (SPH) method to simulate and post-process liquid spray generation. The simulation of a generic annular airblast atomizer is presented, in which a liquid sheet is fragmented by two concentric counter swirling air streams. The accent is put on how the SPH method can bridge the gap between the CAD geometry of a nozzle and its characterization, in terms of spray characteristics and dynamics. In addition, the Lagrangian nature of the SPH method allows to extract additional data to give further insight in the spraying process. First, the sequential breakup events can be tracked from one large liquid blob to very fine stable droplets. This is herein called the tree of fragmentation. From this tree of fragmentation, abstract quantities can be drawn such as the breakup activity and the fragmentation spectrum. Second, the Lagrangian coherent structures in the turbulent flow can be determined easily with the finite-time Lyapunov exponent (FTLE). The extraction of the FTLE is particularly feasible in the SPH framework. Finally, it is pointed out that there is no universal and ultimate non-dimensional number that can characterize airblast primary breakup. Depending on the field of interest, a non-dimensional number (e.g. Weber number) might be more appropriate than another one (e.g. momentum flux ratio) to characterize the regime, and vice versa.

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