Pub Date : 2024-07-15DOI: 10.1007/s40571-024-00802-2
V. Sarfarazi, Ali Ahmadian Saleh, J. Fu, H. Haeri, Mina Tahmasebi Moez, Ali Moayer, N. Golsanami
{"title":"Experimental and numerical study of shear behavior of concrete–soft rock interface: with approach of concrete penetration in rock cavities","authors":"V. Sarfarazi, Ali Ahmadian Saleh, J. Fu, H. Haeri, Mina Tahmasebi Moez, Ali Moayer, N. Golsanami","doi":"10.1007/s40571-024-00802-2","DOIUrl":"https://doi.org/10.1007/s40571-024-00802-2","url":null,"abstract":"","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141649059","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}
Pub Date : 2024-07-11DOI: 10.1007/s40571-024-00795-y
Jie Zhang, Rusong Nie, Yongchang Tan, MaoTong Huang, Yafeng Li, Yipeng Guo
Treating ballast and subgrade soil as an integrated unit for sampling and loading has proven to be an effective method for investigating the interaction between ballast and subgrade soil. Given that direct testing of specimens containing large ballast is constrained by the capabilities of standard laboratory equipment, adopting a model material of smaller size is recommended. Parallel gradation method is widely used for this purpose. This study performed an evaluation of parallel gradation method based on the response of ballast penetration into subgrade soil. Discrete element models were developed to simulate the penetration of crushed ballast, featuring three different parallel gradations, into subgrade soil. On this basis, dynamic triaxial simulations were conducted on these models. By comparing the macroscopic and mesoscopic mechanical characteristics at different scaling ratio, the applicability of the parallel gradation method for assessing ballast penetration into subgrade soil was evaluated. At the macroscopic scale, the scaling ratio of crushed ballast significantly influences the axial, volumetric, and lateral deformations observed during penetration into subgrade soil. Specifically, a smaller average grain size of ballast correlates with reduced deformations in these specimens. The penetration of crushed ballast into subgrade soil significantly increases the porosity of subgrade soil, particularly at the interface between ballast and subgrade. This increase in porosity is more pronounced with larger average grain sizes of ballast. At the mesoscopic scale, larger average grain sizes of ballast lead to more localized high contact forces and more significant stress concentrations. The parallel gradation method substantially affects the mechanical properties of ballast penetration into subgrade soil, at both macroscopic and mesoscopic scales. Therefore, a cautious approach is necessary when relying on this method for precise assessments.
{"title":"Investigation of the parallel gradation method based on response of ballast penetration into subgrade soil by discrete element method","authors":"Jie Zhang, Rusong Nie, Yongchang Tan, MaoTong Huang, Yafeng Li, Yipeng Guo","doi":"10.1007/s40571-024-00795-y","DOIUrl":"https://doi.org/10.1007/s40571-024-00795-y","url":null,"abstract":"<p>Treating ballast and subgrade soil as an integrated unit for sampling and loading has proven to be an effective method for investigating the interaction between ballast and subgrade soil. Given that direct testing of specimens containing large ballast is constrained by the capabilities of standard laboratory equipment, adopting a model material of smaller size is recommended. Parallel gradation method is widely used for this purpose. This study performed an evaluation of parallel gradation method based on the response of ballast penetration into subgrade soil. Discrete element models were developed to simulate the penetration of crushed ballast, featuring three different parallel gradations, into subgrade soil. On this basis, dynamic triaxial simulations were conducted on these models. By comparing the macroscopic and mesoscopic mechanical characteristics at different scaling ratio, the applicability of the parallel gradation method for assessing ballast penetration into subgrade soil was evaluated. At the macroscopic scale, the scaling ratio of crushed ballast significantly influences the axial, volumetric, and lateral deformations observed during penetration into subgrade soil. Specifically, a smaller average grain size of ballast correlates with reduced deformations in these specimens. The penetration of crushed ballast into subgrade soil significantly increases the porosity of subgrade soil, particularly at the interface between ballast and subgrade. This increase in porosity is more pronounced with larger average grain sizes of ballast. At the mesoscopic scale, larger average grain sizes of ballast lead to more localized high contact forces and more significant stress concentrations. The parallel gradation method substantially affects the mechanical properties of ballast penetration into subgrade soil, at both macroscopic and mesoscopic scales. Therefore, a cautious approach is necessary when relying on this method for precise assessments.</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587783","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}
Pub Date : 2024-07-10DOI: 10.1007/s40571-024-00797-w
Shiqi Liu, Zhichao Cheng, Huanling Wang, Yong Zhou, Wei Li
Rockslide is a hot topic and universal phenomenon in the mountainous regions prone to geological hazards, which may pose substantial threats to property. The discrete element method (DEM) has been widely used to simulate the movement process of rockslide and avalanche. However, the rockslide involving jointed rock mass needs more adequate study to evaluate the safety implications effectively. In this paper, a series of DEM tests are conducted to study the movement and fragmentation of blocks with varying structure. The results show that at sliding angle of 45°, horizontal velocity reduces more slowly than vertical velocity because the particles move in a forward direction after impacting the bottom wall. The existence of a baffle structure limits sliding particle movement effectively and enhances the arch effect through the distribution of contact force chains. The number of joints, slope angle and sliding distance have considerable impact on bond breaking percentages and the displacement of the rock mass center. All bond break percentages are close to 90%, and number of joints and slope angle have little impact on the displacement of the rock mass center. This study can guide landslide disaster prevention.
在易发生地质灾害的山区,岩石滑坡是一个热门话题和普遍现象,可能对财产造成重大威胁。离散元法(DEM)已被广泛用于模拟岩石滑坡和雪崩的运动过程。然而,涉及节理岩体的岩崩需要更充分的研究,以有效评估其安全影响。本文进行了一系列 DEM 试验,以研究不同结构岩块的运动和破碎情况。结果表明,在滑动角为 45°时,水平速度的降低速度比垂直速度的降低速度慢,因为颗粒在撞击底壁后会向前运动。挡板结构的存在有效限制了颗粒的滑动运动,并通过接触力链的分布增强了拱形效应。节理数量、斜坡角度和滑动距离对粘结断裂率和岩体中心位移有很大影响。所有粘结破碎率都接近 90%,而节理数和坡度角对岩体中心位移的影响很小。该研究可为滑坡灾害防治提供指导。
{"title":"Discrete element analysis of jointed rock mass impact on rigid baffle structure","authors":"Shiqi Liu, Zhichao Cheng, Huanling Wang, Yong Zhou, Wei Li","doi":"10.1007/s40571-024-00797-w","DOIUrl":"https://doi.org/10.1007/s40571-024-00797-w","url":null,"abstract":"<p>Rockslide is a hot topic and universal phenomenon in the mountainous regions prone to geological hazards, which may pose substantial threats to property. The discrete element method (DEM) has been widely used to simulate the movement process of rockslide and avalanche. However, the rockslide involving jointed rock mass needs more adequate study to evaluate the safety implications effectively. In this paper, a series of DEM tests are conducted to study the movement and fragmentation of blocks with varying structure. The results show that at sliding angle of 45°, horizontal velocity reduces more slowly than vertical velocity because the particles move in a forward direction after impacting the bottom wall. The existence of a baffle structure limits sliding particle movement effectively and enhances the arch effect through the distribution of contact force chains. The number of joints, slope angle and sliding distance have considerable impact on bond breaking percentages and the displacement of the rock mass center. All bond break percentages are close to 90%, and number of joints and slope angle have little impact on the displacement of the rock mass center. This study can guide landslide disaster prevention.</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587852","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}
Pub Date : 2024-07-03DOI: 10.1007/s40571-024-00789-w
Andreas Baumann, Julian Frederic Gerken, Daniel Sollich, Nuwan Rupasinghe, Dirk Biermann, Peter Eberhard
Ejector deep hole drilling achieves high-quality boreholes in production processes. High feed rates are applied to ensure a high productivity level, requiring reliable chip removal from the cutting zone for a stable process. Therefore, a constant metalworking fluid flow under high volume flow rates or high pressure is required. Experimental results show a vortex formation at the outer cutting edge. This vortex can lead to delayed chip removal from the cutting zone, and ultimately, it can lead to chip clogging and result in drill breakage due to increased torque. This paper investigates modified drill head designs using the smoothed particle hydrodynamics method. The investigated modifications include various designs of the chip mouth covering. Besides graphical analysis based on flow visualizations, flow meters are placed at the tool’s head to evaluate the impact of the modifications on the flow rate and possible increased resistance and relocation of the fluid flow from the outer cutting edge to other parts of the tool. The simulation results for the reference design show the experimentally observed vortex formation, validating the simulation model. By adding the tool’s rotation in the SPH simulation, which is not included in the experiments for observation reasons, the vortex formation is positively influenced. In addition, some designs show promising results to further mitigate the vortex formation while maintaining a sufficient fluid flow around the cutting edges.
{"title":"Modeling and mitigation of vortex formation in ejector deep hole drilling with smoothed particle hydrodynamics","authors":"Andreas Baumann, Julian Frederic Gerken, Daniel Sollich, Nuwan Rupasinghe, Dirk Biermann, Peter Eberhard","doi":"10.1007/s40571-024-00789-w","DOIUrl":"https://doi.org/10.1007/s40571-024-00789-w","url":null,"abstract":"<p>Ejector deep hole drilling achieves high-quality boreholes in production processes. High feed rates are applied to ensure a high productivity level, requiring reliable chip removal from the cutting zone for a stable process. Therefore, a constant metalworking fluid flow under high volume flow rates or high pressure is required. Experimental results show a vortex formation at the outer cutting edge. This vortex can lead to delayed chip removal from the cutting zone, and ultimately, it can lead to chip clogging and result in drill breakage due to increased torque. This paper investigates modified drill head designs using the smoothed particle hydrodynamics method. The investigated modifications include various designs of the chip mouth covering. Besides graphical analysis based on flow visualizations, flow meters are placed at the tool’s head to evaluate the impact of the modifications on the flow rate and possible increased resistance and relocation of the fluid flow from the outer cutting edge to other parts of the tool. The simulation results for the reference design show the experimentally observed vortex formation, validating the simulation model. By adding the tool’s rotation in the SPH simulation, which is not included in the experiments for observation reasons, the vortex formation is positively influenced. In addition, some designs show promising results to further mitigate the vortex formation while maintaining a sufficient fluid flow around the cutting edges.\u0000</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529246","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}
Pub Date : 2024-07-01DOI: 10.1007/s40571-024-00783-2
Akanae Chattrairat, Everson Kandare, Sontipee Aimmanee, Phuong Tran, Raj Das
Virtual crime scene investigation using numerical models has the potential to assist in the forensic investigation of firearm-related fatalities, where ethical concerns and expensive resources limit the scope of physical experiments to comprehend the post-impact biomechanics comprehensively. The human cranial numerical model developed in this study incorporates three main components (skin, skull, and brain) with dynamic biomaterial properties. The virtual model provides valuable insights into the post-impact biomechanics of cranial ballistic injuries, particularly in high-speed events beyond conventional investigative capabilities, including the velocity of ejected blood backspatter, cavitation collapsing, and pressure waves. The validation of the numerical model, both quantitatively and qualitatively, demonstrates its ability to replicate similar bone fractures, entrance wound shapes, and backward skin ballooning observed in physical experiments of the human cranial geometry. The model also yields similar temporary cavity sizes, wound sizes, and blood backspatter time against the physical cranial model, aiding in bloodstain pattern analysis. Additionally, the numerical model enables exploration of ballistic factors that vary in each crime scene environment and influence cranial injuries, such as projectile type, velocity, impact location, and impact angle. These established injury patterns contribute to crime scene reconstruction by providing essential information on projectile trajectory, discharge distance, and firearm type, assisting in the resolution of court cases. In conclusion, the developed human cranial geometry in this study offers a reliable tool for investigating firearm-related cranial injuries, serving as a statistical reference in forensic science. Virtual crime scene investigations using these models have the potential to enhance the accuracy and efficiency of forensic analyses.
{"title":"Understanding post-impact biomechanics of ballistic cranial injury by smoothed particle hydrodynamics numerical modelling","authors":"Akanae Chattrairat, Everson Kandare, Sontipee Aimmanee, Phuong Tran, Raj Das","doi":"10.1007/s40571-024-00783-2","DOIUrl":"https://doi.org/10.1007/s40571-024-00783-2","url":null,"abstract":"<p>Virtual crime scene investigation using numerical models has the potential to assist in the forensic investigation of firearm-related fatalities, where ethical concerns and expensive resources limit the scope of physical experiments to comprehend the post-impact biomechanics comprehensively. The human cranial numerical model developed in this study incorporates three main components (skin, skull, and brain) with dynamic biomaterial properties. The virtual model provides valuable insights into the post-impact biomechanics of cranial ballistic injuries, particularly in high-speed events beyond conventional investigative capabilities, including the velocity of ejected blood backspatter, cavitation collapsing, and pressure waves. The validation of the numerical model, both quantitatively and qualitatively, demonstrates its ability to replicate similar bone fractures, entrance wound shapes, and backward skin ballooning observed in physical experiments of the human cranial geometry. The model also yields similar temporary cavity sizes, wound sizes, and blood backspatter time against the physical cranial model, aiding in bloodstain pattern analysis. Additionally, the numerical model enables exploration of ballistic factors that vary in each crime scene environment and influence cranial injuries, such as projectile type, velocity, impact location, and impact angle. These established injury patterns contribute to crime scene reconstruction by providing essential information on projectile trajectory, discharge distance, and firearm type, assisting in the resolution of court cases. In conclusion, the developed human cranial geometry in this study offers a reliable tool for investigating firearm-related cranial injuries, serving as a statistical reference in forensic science. Virtual crime scene investigations\u0000using these models\u0000have the potential to enhance the accuracy and efficiency of forensic analyses.</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505220","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}
Pub Date : 2024-06-29DOI: 10.1007/s40571-024-00791-2
Hadi Bakhshan, Eugenio Oñate, Josep Maria Carbonell
When metals and alloys are exposed to ultrasonic vibrations (UV), a softening behavior occurs, caused by the phenomenon of acousto-plasticity. To obtain accurate results in a deformation analysis, this phenomenon must be included in the formulation of the constitutive material model. In this work, an acoustic-plastic model is proposed to capture the effects of ultrasonic vibrations during machining. The desired effect is to modify the chip morphology to reduce the magnitude of the cutting forces and thus reduce the energy consumption of the process. The study focuses on the modeling of ultrasonic vibration-assisted micromachining (VAMM). The particle finite element method is used and extended to perform a thermo-mechanical analysis capable of capturing the responses of conventional micromachining (CMM) and VAMM operations of 32 HRC stainless steel. The cutting speed and UV parameters, including amplitude and frequency, are integrated into the Johnson–Cook constitutive model to account for the effects of acoustic softening on the machining characteristics. The results show that the influence of UV on microcutting leads to thinner chips and lower cutting force. In the VAMM operations, an average reduction in cutting forces of 20% is achieved at five different cutting speeds. In addition, the contact length between the tool and chip decreases at different cutting speeds from 29% to a maximum of 44%. Furthermore, the thermal analysis results show that there is a negligible temperature change during the CMM and VAMM simulations, indicating that the study of the machining process can focus exclusively on its mechanical aspects when performed at the microscale. The predicted average chip thickness and effective shear angle of the workpiece material are in strong agreement with the experimental results, emphasizing the importance of considering acoustic softening in VAMM studies.
{"title":"Modeling of ultrasonic vibration-assisted micromachining using the particle finite element method","authors":"Hadi Bakhshan, Eugenio Oñate, Josep Maria Carbonell","doi":"10.1007/s40571-024-00791-2","DOIUrl":"https://doi.org/10.1007/s40571-024-00791-2","url":null,"abstract":"<p>When metals and alloys are exposed to ultrasonic vibrations (UV), a softening behavior occurs, caused by the phenomenon of acousto-plasticity. To obtain accurate results in a deformation analysis, this phenomenon must be included in the formulation of the constitutive material model. In this work, an acoustic-plastic model is proposed to capture the effects of ultrasonic vibrations during machining. The desired effect is to modify the chip morphology to reduce the magnitude of the cutting forces and thus reduce the energy consumption of the process. The study focuses on the modeling of ultrasonic vibration-assisted micromachining (VAMM). The particle finite element method is used and extended to perform a thermo-mechanical analysis capable of capturing the responses of conventional micromachining (CMM) and VAMM operations of 32 HRC stainless steel. The cutting speed and UV parameters, including amplitude and frequency, are integrated into the Johnson–Cook constitutive model to account for the effects of acoustic softening on the machining characteristics. The results show that the influence of UV on microcutting leads to thinner chips and lower cutting force. In the VAMM operations, an average reduction in cutting forces of 20% is achieved at five different cutting speeds. In addition, the contact length between the tool and chip decreases at different cutting speeds from 29% to a maximum of 44%. Furthermore, the thermal analysis results show that there is a negligible temperature change during the CMM and VAMM simulations, indicating that the study of the machining process can focus exclusively on its mechanical aspects when performed at the microscale. The predicted average chip thickness and effective shear angle of the workpiece material are in strong agreement with the experimental results, emphasizing the importance of considering acoustic softening in VAMM studies.</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505217","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}
To determine the desirable bonding parameters of the soybean-bonded particle model for accidentally simulating the working process of a pneumatic soybean seed-metering device. Taking the compressive destructive force (Fc,p) derived from the uniaxial compression test of soybean seeds as the evaluation index for the compression simulation tests. The Plackett–Burman and the steepest ascent tests were executed to identify the centroids of the influential factors that substantially affect the bonding force of the soybean-bonded particle model. The optimal values of the significance influencing variables were determined based on the Box–Behnken response surface test. The results indicated that the effect of bonded disk radius (RB,p) between fraction particles on the Fc,p was extremely significant, and the effects of the restitution coefficient (ep-steel) and static friction coefficient (μp-steel) of soybean-steel, normal stiffness per unit area (kn,p) and critical normal stress (σmax,p) were found to be statistically significant. The preferred values identified by Box–Behnken response surface test were 0.520 for ep-steel, 0.274 for μp-steel, 4.082 × 107 N/m3 for kn,p, 3.517 × 105 Pa for σmax,p, and 0.982 mm for RB,p, respectively. The compressive destructive force of soybean seeds was 211.32 N at this point, which was 0.2% less than the measured value of 211.74 N. The results of comparing the grain morphologies during the actual and simulated compressions indicated that the compression states had a superior consistency. It was determined that the DEM simulation input parameters for the soybean-bonded particle model calibrated were proven to be effective and dependable. The investigation presented in this paper can be utilized to effectively analyze the working process of the pneumatic soybean seed-metering devices through coupled simulation. It can also serve as a reference for other researchers to construct a particle model for DEM simulation using the BPM approach.
{"title":"Determination and parameters calibration of the soybean-bonded particle model based on discrete element method","authors":"Dan-Dan Han, Qing Wang, Yun-Xia Wang, Wei Li, Chao Tang, Xiao-Rong Lv","doi":"10.1007/s40571-024-00792-1","DOIUrl":"https://doi.org/10.1007/s40571-024-00792-1","url":null,"abstract":"<p>To determine the desirable bonding parameters of the soybean-bonded particle model for accidentally simulating the working process of a pneumatic soybean seed-metering device. Taking the compressive destructive force (<i>F</i><sub>c<i>,p</i></sub>) derived from the uniaxial compression test of soybean seeds as the evaluation index for the compression simulation tests. The Plackett–Burman and the steepest ascent tests were executed to identify the centroids of the influential factors that substantially affect the bonding force of the soybean-bonded particle model. The optimal values of the significance influencing variables were determined based on the Box–Behnken response surface test. The results indicated that the effect of bonded disk radius (<i>R</i><sub>B<i>,p</i></sub>) between fraction particles on the <i>F</i><sub>c<i>,p</i></sub> was extremely significant, and the effects of the restitution coefficient (<i>e</i><sub>p-steel</sub>) and static friction coefficient (<i>μ</i><sub>p-steel</sub>) of soybean-steel, normal stiffness per unit area (<i>k</i><sub>n<i>,p</i></sub>) and critical normal stress (<i>σ</i><sub>max<i>,p</i></sub>) were found to be statistically significant. The preferred values identified by Box–Behnken response surface test were 0.520 for <i>e</i><sub>p-steel</sub>, 0.274 for <i>μ</i><sub>p-steel</sub>, 4.082 × 10<sup>7</sup> N/m<sup>3</sup> for <i>k</i><sub>n<i>,p</i></sub>, 3.517 × 10<sup>5</sup> Pa for <i>σ</i><sub>max<i>,p</i></sub>, and 0.982 mm for <i>R</i><sub>B<i>,p</i></sub>, respectively. The compressive destructive force of soybean seeds was 211.32 N at this point, which was 0.2% less than the measured value of 211.74 N. The results of comparing the grain morphologies during the actual and simulated compressions indicated that the compression states had a superior consistency. It was determined that the DEM simulation input parameters for the soybean-bonded particle model calibrated were proven to be effective and dependable. The investigation presented in this paper can be utilized to effectively analyze the working process of the pneumatic soybean seed-metering devices through coupled simulation. It can also serve as a reference for other researchers to construct a particle model for DEM simulation using the BPM approach.</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505218","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}
Pub Date : 2024-06-24DOI: 10.1007/s40571-024-00721-2
Zhuolin Wang, Zichao Jiang, Yi Zhang, Gengchao Yang, Trevor Hocksun Kwan, Yuhui Chen, Qinghe Yao
This paper presents a novel method for smoothed particle hydrodynamics (SPH) with thin-walled rigid structures. Inspired by the direct forcing immersed boundary method, this method employs a moving least square method for the velocity interpolation instead of the linear interpolation. It reduces oscillations due to changing relative positions between fluid grids and structures. It also simplifies thin-walled rigid structure simulations by eliminating the need for multiple layers of boundary particles, and improves computational accuracy and stability in three-dimensional scenarios. Results of the impulsively started plate test demonstrate that the proposed method obtains smooth velocity and pressure, as well as a good match to the references results of the vortex wake development. Results of the flow past cylinder test show that the proposed method avoids mutual interference on both side of the boundary, while accurately calculating the forces acting on structure. By comparing to linear least square direct forcing scheme and the diffusive direction scheme, advantages of lower oscillation and higher accuracy are proven. Results of flow past a sphere further indicate the stability of the proposed method for three-dimensional simulations.
{"title":"A moving least square immersed boundary method for SPH with thin-walled rigid structures","authors":"Zhuolin Wang, Zichao Jiang, Yi Zhang, Gengchao Yang, Trevor Hocksun Kwan, Yuhui Chen, Qinghe Yao","doi":"10.1007/s40571-024-00721-2","DOIUrl":"https://doi.org/10.1007/s40571-024-00721-2","url":null,"abstract":"<p>This paper presents a novel method for smoothed particle hydrodynamics (SPH) with thin-walled rigid structures. Inspired by the direct forcing immersed boundary method, this method employs a moving least square method for the velocity interpolation instead of the linear interpolation. It reduces oscillations due to changing relative positions between fluid grids and structures. It also simplifies thin-walled rigid structure simulations by eliminating the need for multiple layers of boundary particles, and improves computational accuracy and stability in three-dimensional scenarios. Results of the impulsively started plate test demonstrate that the proposed method obtains smooth velocity and pressure, as well as a good match to the references results of the vortex wake development. Results of the flow past cylinder test show that the proposed method avoids mutual interference on both side of the boundary, while accurately calculating the forces acting on structure. By comparing to linear least square direct forcing scheme and the diffusive direction scheme, advantages of lower oscillation and higher accuracy are proven. Results of flow past a sphere further indicate the stability of the proposed method for three-dimensional simulations.\u0000</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505219","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}
Pub Date : 2024-06-24DOI: 10.1007/s40571-024-00782-3
S. V. Dharani Raj, Mousumi Mukherjee, Andres Alfonso Peña-Olarte, Roberto Cudmani
Existing literature on true triaxial and torsional shear tests indicate that the mechanical response of a granular assembly is significantly influenced by the magnitude of the intermediate principal stress ratio. The present study aims to explore the mechanism behind such effects in reference to the particle-level interaction using 3D DEM simulations. In this regard, true triaxial numerical simulations have been carried out with constant minor principal stress and varying (b) values employing rolling resistance-type contact model to mimic particle shape. The numerical simulations have been validated against the true triaxial experiments reported in the literature for dense Santa Monica beach sand. The macro-level shearing response of the granular assembly has been examined in terms of the evolution of stress ratio and volumetric strain for different rolling resistance coefficients. Further, such macro-level response has been assessed in reference to the micro-scale attributes, e.g. average contact force, number of interparticle contacts, mechanical coordination number, contact normal orientation, and fabric tensor as well as meso-scale attribute like strong contact force network. Lade’s failure surface has been adopted to represent the stress and fabric at peak state in the octahedral plane, and mathematical expressions have been proposed relating the failure surface parameters to the rolling resistance coefficient.
Graphical abstract
有关真实三轴和扭剪试验的现有文献表明,颗粒组件的机械响应受到中间主应力比大小的显著影响。本研究旨在利用三维 DEM 模拟,参照颗粒级相互作用,探索这种影响背后的机制。为此,采用滚动阻力型接触模型来模拟颗粒形状,在次主应力恒定、(b())值变化的情况下进行了真正的三轴数值模拟。数值模拟结果与文献中报道的针对致密圣莫尼卡海滩砂的真实三轴实验结果进行了验证。通过不同滚动阻力系数下应力比和体积应变的演变,研究了颗粒组件的宏观剪切响应。此外,还参考了微观尺度属性(如平均接触力、颗粒间接触数量、机械配合数、接触法线方向和织物张量)以及中观尺度属性(如强接触力网络),对这种宏观响应进行了评估。采用拉德失效面来表示八面体峰值状态下的应力和织物,并提出了失效面参数与滚动阻力系数之间的数学表达式。
{"title":"Influence of intermediate principal stress and rolling resistance on the shearing response of sand: a micromechanical investigation","authors":"S. V. Dharani Raj, Mousumi Mukherjee, Andres Alfonso Peña-Olarte, Roberto Cudmani","doi":"10.1007/s40571-024-00782-3","DOIUrl":"https://doi.org/10.1007/s40571-024-00782-3","url":null,"abstract":"<p>Existing literature on true triaxial and torsional shear tests indicate that the mechanical response of a granular assembly is significantly influenced by the magnitude of the intermediate principal stress ratio. The present study aims to explore the mechanism behind such effects in reference to the particle-level interaction using 3D DEM simulations. In this regard, true triaxial numerical simulations have been carried out with constant minor principal stress and varying <span>(b)</span> values employing rolling resistance-type contact model to mimic particle shape. The numerical simulations have been validated against the true triaxial experiments reported in the literature for dense Santa Monica beach sand. The macro-level shearing response of the granular assembly has been examined in terms of the evolution of stress ratio and volumetric strain for different rolling resistance coefficients. Further, such macro-level response has been assessed in reference to the micro-scale attributes, e.g. average contact force, number of interparticle contacts, mechanical coordination number, contact normal orientation, and fabric tensor as well as meso-scale attribute like strong contact force network. Lade’s failure surface has been adopted to represent the stress and fabric at peak state in the octahedral plane, and mathematical expressions have been proposed relating the failure surface parameters to the rolling resistance coefficient.</p><h3 data-test=\"abstract-sub-heading\">Graphical abstract</h3>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505221","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}
Pub Date : 2024-06-23DOI: 10.1007/s40571-024-00780-5
Zonglin Li, Ju Chen, Qiang Tian, Haiyan Hu
Discrete element method (DEM) is a powerful tool for the dynamic simulation of irregular non-spherical particle systems. The efficient integration of the rotational motions of numerous particles in DEM poses a big challenge. This paper presents six explicit time integration algorithms, comprising three first-order algorithms and three second-order algorithms, for the rotational motions of non-spherical particles based on the theory of unit quaternion group S(3). The proposed algorithms based on Cayley map do not contain any transcendental function and have high efficiency. The numerical examples underscore the superiority of the first-order symplectic Euler Cayley algorithm (SECay) and the second-order central difference Cayley algorithm (CDCay) in terms of both efficiency and accuracy. In the testing cases of granular systems, SECay and CDCay demonstrate approximately 80% reduction in computational time for the time integration part, compared to the improved predictor–corrector direct multiplication method (IPCDM). Therefore, SECay and CDCay emerge as promising tools for non-spherical DEM simulations.
离散元法(DEM)是对不规则非球形粒子系统进行动态模拟的有力工具。如何在 DEM 中有效地积分众多粒子的旋转运动是一个巨大的挑战。本文基于单位四元数组 S(3) 理论,针对非球形粒子的旋转运动提出了六种显式时间积分算法,包括三种一阶算法和三种二阶算法。所提出的基于 Cayley 映射的算法不包含任何超越函数,具有很高的效率。数值实例凸显了一阶交映欧拉 Cayley 算法(SECay)和二阶中心差分 Cayley 算法(CDCay)在效率和精度方面的优越性。在颗粒系统的测试案例中,与改进的预测器-校正器直接乘法(IPCDM)相比,SECay 和 CDCay 在时间积分部分的计算时间减少了约 80%。因此,SECay 和 CDCay 成为非球形 DEM 仿真的理想工具。
{"title":"Efficient explicit time integration algorithms for non-spherical granular dynamics on group S(3)","authors":"Zonglin Li, Ju Chen, Qiang Tian, Haiyan Hu","doi":"10.1007/s40571-024-00780-5","DOIUrl":"https://doi.org/10.1007/s40571-024-00780-5","url":null,"abstract":"<p>Discrete element method (DEM) is a powerful tool for the dynamic simulation of irregular non-spherical particle systems. The efficient integration of the rotational motions of numerous particles in DEM poses a big challenge. This paper presents six explicit time integration algorithms, comprising three first-order algorithms and three second-order algorithms, for the rotational motions of non-spherical particles based on the theory of unit quaternion group S(3). The proposed algorithms based on Cayley map do not contain any transcendental function and have high efficiency. The numerical examples underscore the superiority of the first-order symplectic Euler Cayley algorithm (SECay) and the second-order central difference Cayley algorithm (CDCay) in terms of both efficiency and accuracy. In the testing cases of granular systems, SECay and CDCay demonstrate approximately 80% reduction in computational time for the time integration part, compared to the improved predictor–corrector direct multiplication method (IPCDM). Therefore, SECay and CDCay emerge as promising tools for non-spherical DEM simulations.</p>","PeriodicalId":524,"journal":{"name":"Computational Particle Mechanics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505223","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}