Computational Particle Mechanics最新文献

{"title":"Lethe-DEM: an open-source parallel discrete element solver with load balancing","authors":"Shahab Golshan,&nbsp;Peter Munch,&nbsp;Rene Gassmöller,&nbsp;Martin Kronbichler,&nbsp;Bruno Blais","doi":"10.1007/s40571-022-00478-6","DOIUrl":"10.1007/s40571-022-00478-6","url":null,"abstract":"<div><p>Approximately <span>({75}%)</span> of the raw material and <span>({50}%)</span> of the products in the chemical industry are granular materials. The discrete element method (DEM) provides detailed insights of phenomena at particle scale, and it is therefore often used for modeling granular materials. However, because DEM tracks the motion and contact of individual particles separately, its computational cost increases nonlinearly <span>(O(n_mathrm{p}log (n_mathrm{p})))</span> – <span>(O(n_mathrm{p}^2))</span> (depending on the algorithm) with the number of particles (<span>(n_mathrm{p})</span>). In this article, we introduce a new open-source parallel DEM software with load balancing: Lethe-DEM. Lethe-DEM, a module of Lethe, consists of solvers for two-dimensional and three-dimensional DEM simulations. Load balancing allows Lethe-DEM to significantly increase the parallel efficiency by <span>(approx {25})</span>–<span>({70}%)</span> depending on the granular simulation. We explain the fundamental modules of Lethe-DEM, its software architecture, and the governing equations. Furthermore, we verify Lethe-DEM with several tests including analytical solutions and comparison with other software. Comparisons with experiments in a flat-bottomed silo, wedge-shaped silo, and rotating drum validate Lethe-DEM. We investigate the strong and weak scaling of Lethe-DEM with <span>({1}le n_mathrm{c} le {192})</span> and <span>({32}le n_mathrm{c} le {320})</span> processes, respectively, with and without load balancing. The strong-scaling analysis is performed on the wedge-shaped silo and rotating drum simulations, while for the weak-scaling analysis, we use a dam-break simulation. The best scalability of Lethe-DEM is obtained in the range of <span>({5000}le n_mathrm{p}/n_mathrm{c} le {15{,}000})</span>. Finally, we demonstrate that large-scale simulations can be carried out with Lethe-DEM using the simulation of a three-dimensional cylindrical silo with <span>(n_mathrm{p}={4.3}times 10^6)</span> on 320 cores.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"10 1","pages":"77 - 96"},"PeriodicalIF":3.3,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4802522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A particle-based parallel scheme for material point method (MPM) using message passing interface (MPI)","authors":"Tak-Hoe Ku,&nbsp;Hyun-Gyu Kim","doi":"10.1007/s40571-022-00480-y","DOIUrl":"10.1007/s40571-022-00480-y","url":null,"abstract":"<div><p>Material point method (MPM) requires a high computational cost associated with mapping information between a background grid and material particles even though it has a great advantage of solving large deformation problems. This paper presents a particle-based parallel scheme for MPM using message passing interface to effectively reduce the computational cost of MPM. Unlike grid-based parallel schemes, computational workloads are evenly distributed over the computing cores by partitioning material particles into balanced particle subsets. The particle-based parallel scheme guarantees an optimal load balancing between the computing cores because the same number of material particles are assigned to each core. The performance of the present particle-based parallel scheme is compared with that of a grid-based parallel scheme.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"10 1","pages":"61 - 76"},"PeriodicalIF":3.3,"publicationDate":"2022-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4696673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation investigation of mechanical and failure characteristics of jointed rock with different shapes of joint asperities under compression loading","authors":"Ya-tao Yan,&nbsp;Si-wei Wang","doi":"10.1007/s40571-022-00477-7","DOIUrl":"10.1007/s40571-022-00477-7","url":null,"abstract":"<div><p>With the increase in the number of rock engineering projects, it has been recognized that the influence of joints on compressive damage of rock mass cannot be ignored. The existence of joints in the rock mass having complex surface configurations significantly influences its damage properties. Hence, a particle flow code (PFC2D) was used to investigate the effects of joint surface configuration on mechanical properties of jointed rock when compressed. In this study, a hybrid model with parallel bond model (PBM) and flat-joint model (FJM) was applied to simulate granite material and the complex surface configuration was simplified into four types of shapes (i.e., rectangle, trapezoid, ellipse and triangle). The shape effect on deformation and failure modes of jointed rock was discussed. The numerical results show that joint asperity diminished mechanical property of jointed rock and is prone to damage. It is reflected that strength and elastic modulus markedly decreased and asperity degradation. In addition, because of the asperity asynchronous degradation, the joint surface exhibited inconsistent displacement. The joint asperity shape affected the failure properties of jointed rock. Three failure modes of the joint asperities were observed. Finally, the shape feature of the asperities (angle, radius ratios and side length) on the deformation and degradation of joint asperity was discussed.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"10 1","pages":"45 - 59"},"PeriodicalIF":3.3,"publicationDate":"2022-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40571-022-00477-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5029790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating DualSPHysics performance implemented in the study of heat transfer in multiphase systems with applications in nuclear reactors","authors":"E. Mayoral-Villa,&nbsp;C. E. Alvarado-Rodríguez,&nbsp;F. Pahuamba-Valdez,&nbsp;J. Klapp,&nbsp;A. M. Gómez-Torres,&nbsp;E. Del Valle-Gallegos,&nbsp;A. Gómez-Villanueva","doi":"10.1007/s40571-022-00476-8","DOIUrl":"10.1007/s40571-022-00476-8","url":null,"abstract":"<div><p>For this work, we condense current endeavors and improvements in the expansion of applications of the DualSPHysics code to nuclear reactor safety analysis, that includes the analysis of very complex multiphysical phenomena, involving, in some cases, a highly nonlinear deformation. Computational fluid dynamic (CFD) codes have been developed to analyze some phenomena in nuclear reactors with very good performance; however, this kind of method, based on a well-defined mesh, presents some restrictions when physical phenomena like thermal expansion change the dimensions of the system. The smoothed particle hydrodynamics (SPH) formulation could represent an option to analyze with more precision some physical phenomena in nuclear reactors where a rigid mesh cannot fully represent the system. The DualSPHysics code has shown to be a real and robust alternative, since it involves a free mesh approach, and the numerical method is very well parallelized in both computational and graphical processing units (CPU and GPU). Five cases have been chosen and studied to validate the developments in the code. The results show an exceptionally good approximation with other simulation approaches and with experimental observations. Based on the analyzed cases, the potential applications for nuclear reactors are discussed. As a result, a development path for the DualSPHysics code has been identified as a starting point to further apply the code in nuclear safety analysis as an innovative technique in the field.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"9 5","pages":"1085 - 1103"},"PeriodicalIF":3.3,"publicationDate":"2022-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4998443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A random algorithm for 3D modeling of solid particles considering elongation, flatness, sphericity, and convexity","authors":"Songling Han,&nbsp;Changming Wang,&nbsp;Xiaoyang Liu,&nbsp;Bailong Li,&nbsp;Ruiyuan Gao,&nbsp;Shuo Li","doi":"10.1007/s40571-022-00475-9","DOIUrl":"10.1007/s40571-022-00475-9","url":null,"abstract":"<div><p>Generating particles with specific shape characteristics is regarded as a critical issue in the research of granular materials. Improving the particle generation method to consider more comprehensive shape descriptors becomes a central challenge in this field. We described a novel solution for parametrically generate non-convex particles to meet this challenge. First, to conveniently capture particle characteristics, this work established estimation functions of 3D shape parameters (elongation, flatness, sphericity, and convexity). Then, the present study proposed a novel stochastic algorithm for generating non-convex particles. (This algorithm successfully controls the above particle shape parameters.) Finally, this work verified the mechanical properties of the generated particles are similar to those of realistic-shaped particles, by comparing the numerical results of three-dimensional compression of granular materials. The proposed algorithm has a good performance in controlling particle shape parameters and generate particles quickly.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"10 1","pages":"19 - 44"},"PeriodicalIF":3.3,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4593452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Material and particle size sensitivity analysis on coefficient of restitution in low-velocity normal impacts","authors":"Niklas Meyer,&nbsp;Eric L. Wagemann,&nbsp;Alexander Jackstadt,&nbsp;Robert Seifried","doi":"10.1007/s40571-022-00471-z","DOIUrl":"10.1007/s40571-022-00471-z","url":null,"abstract":"<div><p>In many granular processes, impacts play a crucial role. These impacts are often described by the coefficient of restitution (COR). This COR does not only depend on impact velocity but also on the material pairing, the shape of impacting bodies, number of impacts, etc. This paper analyzes and compares the sensitivity of the COR for often seen material pairings metal–metal and metal–polymer. For experimental investigations, a steel sphere impacts different planar material probes in a defined manner, e.g., a sphere–wall contact is reproduced. While the metal–metal impacts show a significant dependency on impact velocity, the metal–polymer impacts show only little influence of the impact velocity. Also, repeated impacts onto the same spot have a significant influence on metal–metal impacts, while metal–polymer impacts are not affected. To gain insights not only about the macroscopic behavior of impacts but also about the microscopic behavior, finite element simulations are performed using an efficient 2D axisymmetric model and viscoelastic and elastic–viscoplastic material models. A good agreement between experiments and FEM simulations are achieved for the utilized material pairings. Then, the influence of the sphere’s size is studied. Afterward, a deeper look into the energy dissipation process during contact is investigated. Finally, the contact duration and normal force in the contact zone are studied experimentally.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"9 6","pages":"1293 - 1308"},"PeriodicalIF":3.3,"publicationDate":"2022-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40571-022-00471-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4445530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2D SPH simulation of an anaerobic digester","authors":"Prashant Kumar,&nbsp;Soroush Dabiri,&nbsp;Wolfgang Rauch","doi":"10.1007/s40571-022-00474-w","DOIUrl":"10.1007/s40571-022-00474-w","url":null,"abstract":"<div><p>Understanding the hydrodynamics within the anaerobic digester tank of a wastewater treatment plant is of high importance to ensure sufficient mixing and subsequently a homogeneous distribution of the substrates. In this paper, we demonstrate a two-dimensional computational fluid dynamics simulation of a real-world case study focusing on both, the methodology and the operation of mixing. For this work, DualSPHysics, a Lagrangian solver, has been explored as an alternative to the more commonly used Eulerian solvers in studying the slow-moving dynamics inside a digester tank. This choice of a Lagrangian solver is primarily due to the inherent accounting for advection within the formulation, thus allowing for subsequent modelling of anaerobic digestion processes. A comparison has been made between the simulations from the two methods (Eulerian and Lagrangian), highlighting the benefits and the shortcomings of using smoothed particle hydrodynamics. Concerning operational mixing, the case relies on a draft tube, the effect of which on the velocity profiles has been studied based on the presence of low-velocity zones and Lagrangian coherent structures. Removing the draft tube results in an increase in low-velocity zones by 21.38% while the amount of dead volume increases from 0.52 to 1.2%.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"9 5","pages":"1073 - 1083"},"PeriodicalIF":3.3,"publicationDate":"2022-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40571-022-00474-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4066606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative evaluation of SPH in TIG spot welding","authors":"Stefan Rhys Jeske,&nbsp;Marek Sebastian Simon,&nbsp;Oleksii Semenov,&nbsp;Jan Kruska,&nbsp;Oleg Mokrov,&nbsp;Rahul Sharma,&nbsp;Uwe Reisgen,&nbsp;Jan Bender","doi":"10.1007/s40571-022-00465-x","DOIUrl":"10.1007/s40571-022-00465-x","url":null,"abstract":"<div><p>While the application of the Smoothed Particle Hydrodynamics (SPH) method for the modeling of welding processes has become increasingly popular in recent years, little is yet known about the quantitative predictive capability of this method. We propose a novel SPH model for the simulation of the tungsten inert gas (TIG) spot welding process and conduct a thorough comparison between our SPH implementation and two finite element method (FEM)-based models. In order to be able to quantitatively compare the results of our SPH simulation method with grid-based methods, we additionally propose an improved particle to grid interpolation method based on linear least-squares with an optional hole-filling pass which accounts for missing particles. We show that SPH is able to yield excellent results, especially given the observed deviations between the investigated FEM methods and as such, we validate the accuracy of the method for an industrially relevant engineering application.\u0000</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"10 1","pages":"1 - 18"},"PeriodicalIF":3.3,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40571-022-00465-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4001985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the ability of low-frequency acoustic energy for polishing of the CK60 steel using a hybrid FE/BE/DEM approach","authors":"Sajjad Beigmoradi","doi":"10.1007/s40571-022-00472-y","DOIUrl":"10.1007/s40571-022-00472-y","url":null,"abstract":"<div><p>The polishing process based on abrasive ceramic particles is one of the non-conventional techniques that is hired extensively by manufacturers. There are different methods to generate kinematic energy for abrasive powders in order to impact the workpiece. In this study, low-frequency acoustic energy was utilized directly to provide motion in abrasive grits for the polishing of the CK60 (high carbon steel) workpiece. Wave shape and frequency of excitations were chosen as the two most important of the process parameters that were dependent on the acoustic source. The effects of these parameters on the kinematics of the particles and contact forces were investigated using the discrete element method (DEM). To this end, three main different types of parameters should be defined for modeling the polishing process: size and distribution of particles, particle–particle and particle–workpiece contact parameters, and boundary conditions of the process for different excitations. The shape, size, and distribution of particles were determined using experimental measurements and verified by simulations. Contact parameters between particles and workpiece were derived by experimental techniques. To define the boundary condition of the process, hybrid finite element/boundary element methods were employed to derive the response of the container due to different acoustic excitations and use it as an input for further DEM simulations. Kinematics of particles were computed at different conditions and compared with the experimental particle image velocimetry tests. The numerical results for the particle’s velocity were in good agreement with the experiments. In the next phase, the most efficient condition for polishing process was computed using DEM. Roughness and microscopic studies of the process approved that employing a square wave shape at 70 Hz for acoustic excitation, which was predicted by numerical simulations, enhances the surface quality of the workpiece significantly.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"9 6","pages":"1337 - 1349"},"PeriodicalIF":3.3,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5156568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compatible coupling of discrete elements and finite elements using Delaunay–Voronoi dual tessellations","authors":"Young Kwang Hwang,&nbsp;John E. Bolander,&nbsp;Yun Mook Lim,&nbsp;Jung-Wuk Hong","doi":"10.1007/s40571-022-00473-x","DOIUrl":"10.1007/s40571-022-00473-x","url":null,"abstract":"<div><p>The Voronoi cell lattice model (VCLM) is a discrete approach for simulating the behavior of solids and structures, based on a Voronoi cell partitioning of the domain. In this study, the duality between Voronoi and Delaunay tessellations is used to couple distinct regions represented by VCLM and the finite element method (FEM). By introducing an edge-based smoothing scheme in the FEM, the element frame is transformed from the conventional triangular body to the edge entity. Therefore, along each of the Delaunay edges, both the lattice and finite elements can be defined, which provides several advantages: (a) The regions modeled by each respective approach are clearly distinguished without the need for interface elements, (b) algorithmic efficiency is enhanced during element-wise computations during explicit time integration, and (c) the element performance of the three-node triangular element is improved by introducing the edge-based strain smoothing technique. Selected examples are used to validate the VCLM–FEM coupling approach. Simulations of elastic behavior, geometric nonlinearity, and fracture are conducted. The simulation results agree well with the corresponding theoretical, numerical, and experimental results, which demonstrates the capabilities of the proposed compatible coupling scheme.</p></div>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":"9 6","pages":"1351 - 1365"},"PeriodicalIF":3.3,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5093317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}