Granular Matter最新文献_第9页

Influences of particle size ratio and fines content on the suffusion characteristics of gap-graded soils 粒径比和细粒含量对间隙分级土壤窒息特性的影响

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-04-04 DOI: 10.1007/s10035-024-01425-3

Yi Zhao, Zheng Hu, Yewei Zheng, Qixin Wu

{"title":"Influences of particle size ratio and fines content on the suffusion characteristics of gap-graded soils","authors":"Yi Zhao, Zheng Hu, Yewei Zheng, Qixin Wu","doi":"10.1007/s10035-024-01425-3","DOIUrl":"10.1007/s10035-024-01425-3","url":null,"abstract":"<div><p>Suffusion severely threatens the stability of granular soils supporting infrastructure. While the geometric conditions of the granular soils are intrinsic to their mechanical behavior, their influences on the suffusion characteristics have not been fully understood. This study presents a micro-macro investigation of the suffusion characteristics of gap-graded soils with different fines contents and particle size ratios using the coupled computational fluid dynamics and discrete element method (CFD-DEM). The severity of the suffusion was quantified by both the loss of fines by mass and the volumetric deformation of the specimen. Meanwhile, Voronoi tessellation and weighted Delaunay method were employed to analyze the evolution of pore structures. The evolution of different contact types was used to analyze the rearrangement of the specimen skeleton. The simulation results show that suffusion is aggravated under otherwise identical conditions with an increase in particle size ratio and fines content. The particle size ratio influences the local pore difference between coarse and fine particles, while the fines content influences the fines’ contribution to the soil skeleton. The evolution of the distribution of local void fractions, constriction size distributions, stress-reduction factors, different types of coordination numbers, and different types of contact forces provides useful insights into the microscopic mechanism of the suffusion process.</p></div>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140599666","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}

引用次数: 0

Statistical evaluation of the effect of size and strain rate on particle strength of rockfill materials 粒度和应变率对填石材料颗粒强度影响的统计评估

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-04-01 DOI: 10.1007/s10035-024-01417-3

Shihao Yan, Shichun Chi, Yu Guo, Jinwei Wang, Xinjie Zhou

{"title":"Statistical evaluation of the effect of size and strain rate on particle strength of rockfill materials","authors":"Shihao Yan, Shichun Chi, Yu Guo, Jinwei Wang, Xinjie Zhou","doi":"10.1007/s10035-024-01417-3","DOIUrl":"10.1007/s10035-024-01417-3","url":null,"abstract":"<div><p>The deformation of rockfill materials is mostly caused by particle breakage and subsequent skeleton adjustment. To investigate the effect of size and strain rate on particle strength under seismic load, a series of single particle crushing tests with different sizes and loading rates were conducted. The results show that the particle strength increases with the loading rate, while the size effect on particle strength gradually weakens. Furthermore, within the framework of the weakest chain theory, the failure probability per unit volume and the spatial location distribution of microcracks are discussed, and a statistical model for quasi-static particle strength is established. The spatial location of microcracks follows a power law distribution, and there is a specific power exponent at different strain rates, so that the compound parameters of the particle volume and failure probability are gathered on a master curve determined by the weakest chain statistics. The strain rate effect reduces the failure probability per unit volume and makes the spatial location distribution of microcracks sparser.</p></div>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140353083","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}

引用次数: 0

Scale-up of dry impregnation processes for porous spherical catalyst particles in a rotating drum: experiments and simulations 旋转滚筒中多孔球形催化剂颗粒干法浸渍工艺的放大：实验与模拟

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-30 DOI: 10.1007/s10035-024-01416-4

Pengfei Xu, Yangyang Shen, Bryant Avila, Hernán A. Makse, Maria S. Tomassone

{"title":"Scale-up of dry impregnation processes for porous spherical catalyst particles in a rotating drum: experiments and simulations","authors":"Pengfei Xu, Yangyang Shen, Bryant Avila, Hernán A. Makse, Maria S. Tomassone","doi":"10.1007/s10035-024-01416-4","DOIUrl":"10.1007/s10035-024-01416-4","url":null,"abstract":"<p>Catalyst impregnation is the first step and one of the most crucial steps for preparing industrial catalysts. The process is typically performed in rotating vessels with a spray-nozzle to distribute the liquid onto porous catalyst supports until the pore volume is reached. The inter-particle variability of the impregnated liquid inside the particles significantly affects the activity and selectivity of the resulting catalyst. Current scale-up practices lead to poor fluid distribution and inhomogeneity in the liquid content. The aim of this work is to understand the dynamic behavior of the particles under the spray nozzle, which is essential for desired content uniformity, and to develop a scale-up model for the dry impregnation process. In this work, we considered four dimensionless numbers in the scaling analysis. The scale-up rules require that the dimensionless numbers are kept constant for different scales. Both DEM simulations and matching experiments of dry impregnation inside the porous particles were performed for different vessel sizes. The water content of the particles was compared for different times and locations, and the relative standard deviation is calculated from the axial water content. Simulation and experimental results show that particles achieve similar content uniformity at the end of impregnation, confirming that the scale-up rules are applicable to all vessel sizes. The dimensionless numbers give very good scale-up performance since curves collapse indicating similarity in the processes. In addition, the scale-up method is validated for different particle sizes in simulations.</p>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10035-024-01416-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140599756","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}

引用次数: 0

Investigation on the spreading behaviour of sand powder used in binder jet 3D printing 关于粘合剂喷射三维打印中使用的砂粉扩散行为的研究

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-29 DOI: 10.1007/s10035-024-01420-8

Yulun Xu, Lanzhou Ge, Wenguang Nan

{"title":"Investigation on the spreading behaviour of sand powder used in binder jet 3D printing","authors":"Yulun Xu, Lanzhou Ge, Wenguang Nan","doi":"10.1007/s10035-024-01420-8","DOIUrl":"10.1007/s10035-024-01420-8","url":null,"abstract":"<div><p>The spreading behaviour of cohesive sand powder is modelled by Discrete Element Method, and the spreadability and the mechanical jamming are focused. The empty patches and total particle volume of the spread layer are examined, followed by the analysis of the geometry force and jamming structure. The results show that several empty patches with different size and shapes could be observed within the spread layer along the spreading direction even when the gap height increases to 3.0<i>D</i><sub>90</sub>. Large particles are more difficult to be spread onto the base due to jamming, although their size is smaller than the gap height. Size segregation of particles occurs before particles entering the gap between the blade and base. There are almost no particles on the smooth base when the gap height is small, due to the full-slip flow of particles. The difference of the spread layer and spreadability between the cases with rough and smooth base is reduced by the increase of the gap height. An interesting correlation between jamming effect and local defects (empty spaces) in the powder layer is identified. The resistance to particle rolling is important for the mechanical jamming reported in this work. The jammed particles with a larger size ratio tend to be more stable.</p></div>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140325328","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}

引用次数: 0

Discrete element study of stresses and deformation on gravity retaining wall under static loading 静力荷载下重力挡土墙应力和变形的离散元素研究

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-28 DOI: 10.1007/s10035-024-01422-6

Prerna Singh, Tanusree Chakraborty, Puneet Mahajan

{"title":"Discrete element study of stresses and deformation on gravity retaining wall under static loading","authors":"Prerna Singh, Tanusree Chakraborty, Puneet Mahajan","doi":"10.1007/s10035-024-01422-6","DOIUrl":"10.1007/s10035-024-01422-6","url":null,"abstract":"<div><p>The study of gravity retaining wall supporting cohesionless soil is performed using the discrete element software Particle Flow Code (PFC), with emphasis on three-dimensional analysis at the grain scale, covering the transition from the initial state to the active state. The soil particles are represented by spherical balls and the rolling resistance linear contact model is used to include the shape effect. The rigid balls are connected by linear parallel bond contact model with a specified strength and stiffness to replicate the physical characteristics of retaining wall. The domain size is reduced by using high g criteria and scaling laws to enhance computational efficiency. The earth pressure coefficient obtained from the present study is compared with the existing analytical and experimental solutions. It is concluded that widely used Coulomb and Rankine methods underestimate the active earth pressure. The total earth thrust acting on the gravity wall is 67.3 kN/m acting at 0.301<i>H</i> above the wall base. The initial state shows a decrease in average coordination number from 5.0 to 3.3 at wall top indicating the debonding of grains and simultaneous decrease in density. In addition, the force chain distribution, porosity, lateral displacement, and axial displacement are investigated. A correlation between the earth pressure coefficient and lateral displacement is also established. The discrete analysis provided valuable insights into the particle-level mechanisms underlying the overall behavior of the retaining wall, contributing to a better understanding of its continuum response.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140325322","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}

引用次数: 0

A study of membrane correction accounting for both curvature and tension in DEM simulations of triaxial tests of sand and ballast with two alternative flexible membrane models 在使用两种可选柔性膜模型对砂和压载物的三轴试验进行 DEM 模拟时，对同时考虑曲率和拉力的膜校正进行研究

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-25 DOI: 10.1007/s10035-024-01419-1

Mathias Tolomeo, Glenn R. McDowell

{"title":"A study of membrane correction accounting for both curvature and tension in DEM simulations of triaxial tests of sand and ballast with two alternative flexible membrane models","authors":"Mathias Tolomeo, Glenn R. McDowell","doi":"10.1007/s10035-024-01419-1","DOIUrl":"10.1007/s10035-024-01419-1","url":null,"abstract":"<div><p>In DEM simulations of triaxial tests, modelling a flexible lateral membrane is crucial and challenging. It is essential for the correct application of a uniform lateral pressure and for an accurate measurement of sample volume. Here, we introduce a membrane made of triangular facets, and model it as a continuum; we then compare this approach with a well-established method that uses a layer of bonded spheres. With either method, it is also possible to assess the additional stress applied by the membrane as it deforms, i.e. the difference between the stress applied at the boundary and the actual stress within the sample. It is shown that this difference has two origins: the tension developed in the membrane, as it deforms; and the curvature of the membrane, since this causes a vertical component of the confining pressure which can be significant. These findings may be used to inform and improve the membrane correction commonly used in experiments, where similar effects occur.</p><h3>Graphic abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10035-024-01419-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140299533","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}

引用次数: 0

Collision time in the inelastic bouncing ball model of granular materials 颗粒材料非弹性弹跳球模型中的碰撞时间

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-21 DOI: 10.1007/s10035-024-01403-9

Junius André F. Balista, Christian Jay P. Magsigay, Caesar A. Saloma

{"title":"Collision time in the inelastic bouncing ball model of granular materials","authors":"Junius André F. Balista, Christian Jay P. Magsigay, Caesar A. Saloma","doi":"10.1007/s10035-024-01403-9","DOIUrl":"10.1007/s10035-024-01403-9","url":null,"abstract":"<div><p>We modified the inelastic bouncing ball model (IBBM) to account for the role of collision time <span>({tau }_{c})</span> in defining the dynamics of vertically vibrated confined granular systems. Although <span>({tau }_{c})</span> was surmised to be consequential for dissipative systems, previous studies on the accuracy of IBBM did not formally incorporate <span>({tau }_{c})</span> as a dynamical variable of the model, focusing instead on other factors during flight, such as air friction. We utilized the discrete element method (DEM) to study the role of <span>({tau }_{c})</span> in the granular dynamics, and to cross-validate the efficacy of our reformulation of IBBM to account for the effect of collisions. When the <span>({tau }_{c})</span> value is greater than that of <span>({t}_{0})</span>, which is the first instance that the container acceleration exceeds the gravitational acceleration <span>(g)</span>, the time-of-flight decreases, and the location of the bifurcation point shifts in the bifurcation diagram (time-of-flight versus dimensionless acceleration). We model <span>({tau }_{c})</span> as representing the range of uncertainty in the occurrence of <span>({t}_{0})</span>. Assuming a separation of timescale between the dynamics of the collision between the center-of-mass (CM) of the granular system and the container, and the time-of-flight of the CM itself, we propose a supporting but separate model for the dependence of <span>({tau }_{c})</span> on <i>Γ</i>. The time-of-flight duration is determined when <span>({tau }_{c})</span> is known in the modified IBBM that now produces bifurcation diagrams which are in closer agreement with the DEM simulation results.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140202007","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}

引用次数: 0

Ballast crushing probability model considering the influence of particle morphology and size 考虑颗粒形态和大小影响的压载破碎概率模型

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-20 DOI: 10.1007/s10035-024-01414-6

Rui Gao, Zhiwen Yuan, Qihang Hu, Jing Chen

{"title":"Ballast crushing probability model considering the influence of particle morphology and size","authors":"Rui Gao, Zhiwen Yuan, Qihang Hu, Jing Chen","doi":"10.1007/s10035-024-01414-6","DOIUrl":"10.1007/s10035-024-01414-6","url":null,"abstract":"<p>The non-uniform shape and diverse dimensions exert a substantial influence on the distribution of forces within the ballast, hence affecting its bearing capacity. The objective of this work was to investigate the interrelated impact of particle shape and size on ballast strength, and then construct a prediction model that could estimate the chance of ballast crushing. For these purposes, both three-dimensional scanning and single-particle compression tests were undertaken. The morphology of ballast particles at various scales was comprehensively characterized by computing diverse parameters based on the scanning results. The present study systematically assessed the impact of size, overall shape and roundness on particle crushing behavior and parameters. Then a novel approach was introduced to calculate characteristic strength, taking into account the influence of particle morphology. A ballast crushing probability distribution model was established, which incorporated the Weibull model. The anticipation of ballast crushing probabilities can be achieved within this framework by analyzing particle size and morphology parameters. At last, the actual crushing probabilities were compared to the predicted probabilities for a sample of 50 randomly chosen ballasts. The results revealed that 80% of the particles displayed a deviation of less than 10%, which proved the accuracy of the applied method.</p>","PeriodicalId":49323,"journal":{"name":"Granular Matter","volume":"26 2","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140202113","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}

引用次数: 0

Gas flow patterns in a granular fluidized bed 颗粒流化床中的气体流动模式

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-18 DOI: 10.1007/s10035-024-01415-5

Wilson Barros Jr.

引用次数: 0

Structural fluctuations in thin cohesive particle layers in powder-based additive manufacturing 基于粉末的增材制造中薄内聚颗粒层的结构波动

IF 2.4 3区工程技术

Granular Matter Pub Date : 2024-03-13 DOI: 10.1007/s10035-024-01410-w

Sudeshna Roy, Hongyi Xiao, Vasileios Angelidakis, Thorsten Pöschel

引用次数: 0