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基于DPM-VOF耦合的高铅渣底吹还原炉内多相流动数值模拟
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作者 闫红杰 黄正宗 +2 位作者 郝澳 夏韬 刘柳 《中国有色金属学报》 北大核心 2025年第2期607-620,共14页
高铅渣底吹还原炉内天然气-熔体或载气-熔体-煤粉构成的多相体系复杂行为与熔炼效率和系统产能紧密相关。本文基于DPM-VOF耦合模型,研究了工业尺度的高铅渣底吹还原炉内分别以天然气和煤粉为还原剂的气-液两相流和气-液-固多相流复杂行... 高铅渣底吹还原炉内天然气-熔体或载气-熔体-煤粉构成的多相体系复杂行为与熔炼效率和系统产能紧密相关。本文基于DPM-VOF耦合模型,研究了工业尺度的高铅渣底吹还原炉内分别以天然气和煤粉为还原剂的气-液两相流和气-液-固多相流复杂行为。结果表明:天然气作还原剂时,炉膛两端熔体流速平缓,喷枪区域流速剧烈,呈“脉冲状”分布;喷枪附近压力呈两侧大、中间小的“V”字形分布;喷枪区域压力波动剧烈,虽可强化气液搅拌过程但易造成喷枪损坏和熔体喷溅。采用煤粉作还原剂时,煤粉从喷枪喷出后最初分布在气团内部和气液交界面处,随后扩散至熔池中上部和烟气区域;熔池内煤粉分布在0.25~0.85 m深度范围;喷枪附近煤粉浓度相近,均未出现沉积现象。 展开更多
关键词 底吹还原炉 多相流 dpm-VOF模型 数值模拟 直接炼铅工艺
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基于CFD-DPM模型的不同生态抛枕防护效果分析
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作者 孙洪广 洪良贞 +1 位作者 王茂枚 王连 《长江科学院院报》 北大核心 2025年第4期19-26,44,共9页
天然河道中弯曲边坡是受侵蚀的严重区域,弯曲边坡防护是河道治理的重大难题。基于生态护坡理念,对比研究了砂石填装的不同形状抛枕在弯道侵蚀中的防护效果。根据实际河道结构,构建了弯道河床几何模型,进而利用计算流体力学-离散相模型(C... 天然河道中弯曲边坡是受侵蚀的严重区域,弯曲边坡防护是河道治理的重大难题。基于生态护坡理念,对比研究了砂石填装的不同形状抛枕在弯道侵蚀中的防护效果。根据实际河道结构,构建了弯道河床几何模型,进而利用计算流体力学-离散相模型(CFD-DPM)方法分析在弯曲河道凹岸侧投放长方体、半球体和半圆柱体抛枕的护岸效果。分析结果表明:在水流速度v=0.5 m/s的条件下,放置有抛枕的3种模型中,长方体抛枕附近的凹岸受到的压力最小,半圆柱体抛枕中颗粒雷诺数最小;半圆柱体抛枕阻挡的颗粒量最多、颗粒的平均速度最小,比无抛枕模型中的颗粒平均速度小9%;放置长方体抛枕的护岸模式下,对抛枕附近的凹岸有较好的防护效果,放置半圆柱体抛枕的护岸模式下,阻沙效果最佳。 展开更多
关键词 弯曲边坡防护 生态护坡 砂石抛枕 弯道河床几何模型 CFD-dpm方法 防护效果
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Comparative study on the oblique water-entry of high-speed projectile based on rigid-body and elastic-plastic body model 被引量:1
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作者 Xiangyan Liu Xiaowei Cai +3 位作者 Zhengui Huang Yu Hou Jian Qin Zhihua Chen 《Defence Technology(防务技术)》 2025年第4期133-155,共23页
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc... To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°. 展开更多
关键词 Fluid-structure interaction Rigid-body model Elastic-plastic model Structural deformation Impact loads Structural safety of projectile
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Deformation mechanism of a novel pipe-roof composite slab:An experimental and theoretical investigation
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作者 LU Bo JIA Peng-jiao +3 位作者 ZHAO Wen NI Peng-peng BAI Qian CHENG Cheng 《Journal of Central South University》 2025年第3期1044-1059,共16页
Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space developmen... Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space development. Whilst the load-bearing of pipe-roof structures has been the subject of much research, uncertainties of deformation mechanism and the derivation of reliable calculation methods remain a challenge. For efficient design and wider deployment, this paper presents a bidirectional bending test to investigate the bending stiffnesses, load capacities and deformation mechanisms. The results show that the STS specimens exhibit good ductility and experience bending failure, and their deformation curves follow a half-sine wave upon loading. On this basis, the development of an STS composite slab deformation prediction model is proposed, along with the estimation for its bending stiffness. Theoretical predictions are shown to be in good agreement with the experimental measurements, with a maximum error of less than 15%. The outcomes of this investigation can provide references for the design and application of STS structures. 展开更多
关键词 steel tube slab deformation characteristics bending stiffness theoretical model
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基于CFD-DPM的SCR脱硝蜂窝状催化剂磨损特性研究
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作者 陈路敏 钱付平 +5 位作者 朱晨 于灵涛 李海金 高艺华 吴越 黄乃金 《中国电机工程学报》 北大核心 2025年第13期5163-5172,I0019,共11页
利用计算流体力学-离散元(computational fluid dynamics-discrete phase model,CFD-DPM)数值模拟方法,对水泥窑选择性催化还原法(selective catalytic reduction,SCR)反应器脱硝单通道催化剂的磨损冲蚀进行研究,分析催化剂各部位磨损... 利用计算流体力学-离散元(computational fluid dynamics-discrete phase model,CFD-DPM)数值模拟方法,对水泥窑选择性催化还原法(selective catalytic reduction,SCR)反应器脱硝单通道催化剂的磨损冲蚀进行研究,分析催化剂各部位磨损冲蚀形貌,获取其不同部位冲蚀磨损特性。结果表明:飞灰颗粒对催化剂端面的碰撞破坏最严重,水泥窑SCR脱硝催化剂端面拐角磨损风险最高,磨损范围在催化剂沿程的前3%。在2~7 m/s内催化剂壁面的最大磨损率随速度的增加呈现先减小后增大的趋势。在0~90°入射角范围内整体磨损率呈正态分布,入射角为45°时存在磨损峰。当入射角由45°峰值调整到5°时,催化剂平均磨损率下降56.47%。入射角大于45°的磨损率虽也呈下降趋势,但其对催化剂端面的磨损作用大于小入射角的情况,工程中尽量将烟气入射角维持在至少20°以下,减少烟气入射角对催化剂前部的磨损。 展开更多
关键词 水泥窑烟气 计算流体力学-离散元 催化剂磨损 磨损率
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Dislocation density model and microstructure of 7A85 aluminum alloy during thermal deformation 被引量:10
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作者 HU Jian-liang WU Xiu-jiang +3 位作者 BO Hong JIAO Zi-teng HUANG Shi-quan JIN Miao 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第10期2999-3007,共9页
The microstructure evolution of 7A85 aluminum alloy at the conditions of strain rate(0.001−1 s^(−1))and deformation temperature(250−450°C)was studied by optical microscopy(OM)and electron back scattering diffract... The microstructure evolution of 7A85 aluminum alloy at the conditions of strain rate(0.001−1 s^(−1))and deformation temperature(250−450°C)was studied by optical microscopy(OM)and electron back scattering diffraction(EBSD).Based on the K-M dislocation density model,a two-stage K-M dislocation density model of 7A85 aluminum alloy was established.The results reveal that dynamic recovery(DRV)and dynamic recrystallization(DRX)are the main mechanisms of microstructure evolution during thermal deformation of 7A85 aluminum alloy.350−400°C is the transformation zone from dynamic recovery to dynamic recrystallization.At low temperature(≤350°C),DRV is the main mechanism,while DRX mostly occurs at high temperature(≥400°C).At this point,the sensitivity of microstructure evolution to temperature is relatively high.As the temperature increased,the average misorientation angle(θˉ_(c))increased significantly,ranging from 0.93°to 7.13°.Meanwhile,the f_(LAGBs) decreased with the highest decrease of 24%. 展开更多
关键词 hot deformation microstructure evolution dynamic recrystallization dislocation density model
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A model of deformation of thin-wall surface parts during milling machining process 被引量:11
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作者 王凌云 黄红辉 +2 位作者 Rae W.WEST 李厚佳 杜继涛 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第5期1107-1115,共9页
A three-dimensional finite element model was established for the milling of thin-walled parts. The physical model of the milling of the part was established using the AdvantEdge FEM software as the platform. The alumi... A three-dimensional finite element model was established for the milling of thin-walled parts. The physical model of the milling of the part was established using the AdvantEdge FEM software as the platform. The aluminum alloy impeller was designated as the object to be processed and the boundary conditions which met the actual machining were set. Through the solution, the physical quantities such as the three-way cutting force, the tool temperature, and the tool stress were obtained, and the calculation of the elastic deformation of the thin-walled blade of the free-form surface at the contact points between the tool and the workpiece was realized. The elastic deformation law of the thin-walled blade was then predicted. The results show that the maximum deviation between the predicted value and the actual measured machining value of the elastic deformation was 26.055 μm; the minimum deviation was 2.011 μm, with the average deviation being 10.154 μm. This shows that the prediction is in close agreement with the actual result. 展开更多
关键词 thin-walled surface parts milling force elastic deformation finite element model
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Hot deformation behavior and constitutive modeling of Q345E alloy steel under hot compression 被引量:6
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作者 钱东升 彭亚亚 邓加东 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第2期284-295,共12页
Q345E as one of typical low alloy steels is widely used in manufacturing basic components in many fields because of its eminent formability under elevated temperature. In this work, the deformation behavior of Q345E s... Q345E as one of typical low alloy steels is widely used in manufacturing basic components in many fields because of its eminent formability under elevated temperature. In this work, the deformation behavior of Q345E steel was investigated by hot compression experiments on Gleeble-3500 thermo-mechanical simulator with the temperature ranging from 850 ℃ to 1150 ℃ and strain rate ranging from 0.01 s-1 to 10 s-1. The experimental results indicate that dynamic softening of Q345E benefits from increasing deformation temperature and decreasing strain rate. The mathematical relationship between dynamic softening degree and deformation conditions is established to predict the dynamic softening degree quantitatively, which is further proved by some optical microstructures of Q345E. In addition, the experimental results also reveal that the stress level decreases with increasing deformation temperature and decreasing strain rate. The constitutive equation for flow stress of Q345E is formulated by Arrihenius equation and the modified Zener-Hollomon parameter considering the compensation of both strain and strain rate. The flow stress values predicted by the constitutive equation agree well with the experimental values, realizing the accurate prediction of the flow stress of Q345E steel under hot deformation. 展开更多
关键词 hot deformation behavior dynamic softening flow stress constitutive model
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Permanent deformation and prediction model of construction and demolition waste under repeated loading 被引量:7
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作者 HUANG Chao ZHANG Jun-hui +2 位作者 ZHANG An-shun LI Jue WANG Xin-yu 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第4期1363-1375,共13页
This study aims to reveal the macroscopic permanent deformation(PD)behavior and the internal structural evolution of construction and demolition waste(CDW)under loading.Firstly,the initial matric suction of CDW was me... This study aims to reveal the macroscopic permanent deformation(PD)behavior and the internal structural evolution of construction and demolition waste(CDW)under loading.Firstly,the initial matric suction of CDW was measured by the filter paper method.Secondly,the PD of CDW with different humidity and stress states was investigated by repeated load triaxial tests,and a comprehensive prediction model was established.Finally,the discrete element method was performed to analyze the internal structural evolution of CDW during deformation.These results showed that the VAN-GENUCHTEN model could describe the soil-water characteristic curve of CDW well.The PD increases with the increase of the deviator stress and the number of cyclic loading,but the opposite trend was observed when the initial matric suction and confining pressure increased.The proposed model in this study provides a satisfactory prediction of PD.The discrete element method could accurately simulate the macroscopic PD of CDW,and the shear force,interlock force and sliding content increase with the increase of deviator stress during the deformation.The research could provide useful reference for the deformation stability analysis of CDW under cyclic loading. 展开更多
关键词 construction and demolition waste subgrade filler permanent deformation discrete element method prediction model
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Modeling of metadynamic recrystallization kinetics after hot deformation of low-alloy steel Q345B 被引量:3
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作者 马博 彭艳 +1 位作者 刘云飞 贾斌 《Journal of Central South University》 SCIE EI CAS 2010年第5期911-917,共7页
Based on the steady-state strain measured by single-pass hot compression tests,the method by a double-pass hot compression testing was developed to measure the metadynamic-recrystallization kinetics.The metadynamic re... Based on the steady-state strain measured by single-pass hot compression tests,the method by a double-pass hot compression testing was developed to measure the metadynamic-recrystallization kinetics.The metadynamic recrystallization behavior of low-alloy steel Q345B during hot compression deformation was investigated in the temperature range of 1 000-1 100℃,the strain rate range of 0.01-0.10 s -1 and the interpass time range of 0.5-50 s on a Gleeble-3500 thermo-simulation machine.The results show that metadynamic recrystallization during the interpass time can be observed.As the deformation temperature and strain rate increase,softening caused by metadynamic recrystallization is obvious.According to the data of thermo-simulation,the metadynamic recrystallization activation energy is obtained to be Qmd=100.674 kJ/mol and metadynamic recrystallization kinetics model is set up.Finally,the error analysis of metadynamic recrystallization kinetics model proves that the model has high accuracy(correlation coefficient R=0.988 6). 展开更多
关键词 low-alloy steel kinetics model hot deformation metadynamic recrystallization activation energy
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Elastoplastic model for discontinuous shear deformation of deep rock mass 被引量:3
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作者 王明洋 范鹏贤 +1 位作者 钱七虎 邓宏见 《Journal of Central South University》 SCIE EI CAS 2011年第3期866-873,共8页
Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechan... Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechanism,the complete deformation process of deep rock mass,with a great emphasis on local shear deformation stage,was analyzed in detail.The quasi continuous shear deformation of the deep rock mass is described by a combination of smooth functions:the averaged distribution of the original deformation field,and the local discontinuities along the slip lines.Hence,an elasto-plastic model is established for the shear deformation process,in which the rotational displacement is taken into account as well as the translational component.Numerical analysis method was developed for case study.Deformation process of a tunnel under high earth stress was investigated for verification. 展开更多
关键词 deep rock mass discontinuous deformation elasto-plastic model
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基于VOF-DPM模型的明渠含沙数值模拟及量水方案比选 被引量:1
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作者 唐渊 马文波 +5 位作者 温红艳 王国强 申丽霞 吴建华 张玉胜 成一雄 《人民黄河》 CAS 北大核心 2024年第11期126-132,148,共8页
为探究含沙水流对明渠流量测量精度的影响,基于Fluent软件采用VOF-DPM模型对明渠进行数值模拟,分别模拟不同进口流速和含沙量组合条件下渠道内流量、液位及泥沙颗粒分布,并将数值模拟结果与试验结果进行对比分析,计算出各量水设施的流... 为探究含沙水流对明渠流量测量精度的影响,基于Fluent软件采用VOF-DPM模型对明渠进行数值模拟,分别模拟不同进口流速和含沙量组合条件下渠道内流量、液位及泥沙颗粒分布,并将数值模拟结果与试验结果进行对比分析,计算出各量水设施的流量误差与液位误差。结果表明:采用VOF-DPM模型可以较好地模拟含沙水流在明渠的流态,通过开展不同流量级的流量测试可知,在不同含沙量条件下,巴歇尔槽流量计误差最小(-3%~1%),超声流量计(-4%~3%)和电磁流量计(-9%~2%)量测效果均较好,雷达流量计误差较大(-20%~4%),说明非接触式流量计在高含沙量、大流量的情况下需进一步提高测量精度;超声液位、电磁液位与雷达液位误差均较大,试验中尾部巴歇尔槽壅水以及泥沙在渠道底部淤积是造成较大液位误差的原因之一。 展开更多
关键词 数值模拟 VOF-dpm模型 含沙量 测流精度
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基于CFD-DPM模型的T型网式过滤器冲蚀特性模拟与分析 被引量:1
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作者 项旭东 张钟莉莉 +2 位作者 曾揭峰 郑强 杨培岭 《排灌机械工程学报》 CSCD 北大核心 2024年第9期900-906,共7页
为分析滤网冲蚀情况,采用多孔阶跃模型和滤网缩尺模型,结合CFD-DPM两相流模型通过主因素分析方法对滤网冲蚀速率规律进行数值模拟分析与预测,探求整体不同区域滤网的冲蚀效应情况,并通过基于正交试验的多因素主效应分析得出各因素对最... 为分析滤网冲蚀情况,采用多孔阶跃模型和滤网缩尺模型,结合CFD-DPM两相流模型通过主因素分析方法对滤网冲蚀速率规律进行数值模拟分析与预测,探求整体不同区域滤网的冲蚀效应情况,并通过基于正交试验的多因素主效应分析得出各因素对最大冲蚀速率的影响显著性大小.结果表明:在一定范围内最大冲蚀速率与颗粒粒径呈负相关而与质量流率、流速呈正相关;滤网表面中滤孔面普遍比迎水面更易受冲蚀破坏,背水面几乎不受冲蚀影响;颗粒粒径、质量流率对冲蚀高发区域范围大小影响较小(面积增幅为15.0%~16.7%),而流速对其影响较明显(面积增幅为50.0%);显著性检验中,流速、质量流率、颗粒粒径对最大冲蚀速率的P值分别为0.01280,0.00269和3.712×10^(-9),均呈显著性相关. 展开更多
关键词 网式过滤器 dpm模型 冲蚀速率 显著性分析 正交试验
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Several Typical Geomechanical Models of Deformation Fracture of Mountain in High Earthquake Intensity Area
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作者 Xiangning Xu,Lansheng Wang 1.Chengdu University of Technology,Chengdu,610059,China. 2.Chengdu Center of Hydrogeology and Engineering Geology of Sichuan Provincial GMR Bureau,Chengdu,610081,China 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期72-72,共1页
The deformation fracture and stability of mountain under the earthquake action is an important issue that arouses concern of researchers in the field of engineering geology.The authors,from 2000 to 2006, selected the ... The deformation fracture and stability of mountain under the earthquake action is an important issue that arouses concern of researchers in the field of engineering geology.The authors,from 2000 to 2006, selected the 1933 earthquake in Diexi zone as a typical study site to carry out the genetic mechanism research of mountain deformation-fracture caused by earthquake; in order to have comparability,the breadth 展开更多
关键词 HIGH earthquake intensity area deformATION FRACTURE mechanism Geo-mechanical model bedded LANDSLIDE model COLLAPSING model LANDSLIDE model
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Mathematical model of deformation resistance of 30 MnSi V steel
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作者 戴铁军 刘战英 +1 位作者 刘相华 王国栋 《中国有色金属学报》 EI CAS CSCD 北大核心 2001年第z1期210-212,共3页
Based on 30MnSiV steel, the deformation resistance was studied by using Gleeble 1500 thermomechanical simulator. The mathematical model of the deformation resistance is established by analyzing the relationship of the... Based on 30MnSiV steel, the deformation resistance was studied by using Gleeble 1500 thermomechanical simulator. The mathematical model of the deformation resistance is established by analyzing the relationship of the deformation temperature, deformation rate and deformation resistance. The regression equation is highly noticeable by means of regression analysis. The mathematical model corresponds to test data by means of the contrast. 展开更多
关键词 thermomechanical simulator mathematical model regression deformation resistance
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Case study on the mechanics of NPR anchor cable compensation for large deformation tunnel in soft rock in the Transverse Mountain area,China 被引量:1
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作者 LI Yong ZHENG Jing +3 位作者 HUO Shu-sen WANG Feng-nian HE Man-chao TAO Zhi-gang 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第6期2054-2069,共16页
A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced duri... A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced during the tunnel construction.To mitigate this problem,a support system was designed incorporating negative Poisson ratio(NPR)anchor cables with negative Poisson ratio effect.Physical model experiments,field experiments,and numerical simulation experiments were conducted to investigate the compensation mechanical behavior of NPR anchor cables.The large deformations of soft rocks in the Daliangshan Tunnel are caused by a high ground stress,a high degree of joint fracture development,and a high degree of surrounding rock fragmentation.A compensation mechanics support system combining long and short NPR anchor cables was suggested to provide sufficient counter-support force(approximately 350 kN)for the surrounding rock inside the tunnel.Comparing the NPR anchor cable support system with the original support system used in the Daliangshan tunnel showed that an NPR anchor cable support system,combining cables of 6.3 m and 10.3 m in length,effectively prevented convergence of surrounding rock deformation,and the integrated settlement convergence value remained below 300 mm.This study provides an effective scientific basis for resolving large deformation problems in deeply buried soft rocks in western transverse mountain areas. 展开更多
关键词 soft rock large deformation NPR anchor cable physical model numerical simulation compensation mechanics
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Short-term deformation behavior model of endangered earthen heritage slope after conservation in Jiaohe Ruins
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作者 张景科 谌文武 和法国 《Journal of Central South University》 SCIE EI CAS 2012年第7期2029-2036,共8页
Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitati... Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitative evaluation of interactions between soil mass and structures as well as the forecast. Based on cliff conservation engineering of Jiaohe Ruins (the largest raw soil heritage site in the world), data of horizontal deformation of the upper cliff were obtained by using Nanrui-made NDW-50 displacement device (precision: 0.01 mm, frequency: 15 min^-l). Regression analysis indicates that deformation behavior models include exponential growth, linear growth and parabolic growth types, while daily deformation presents more intense periodicity (24 h). The deformation is less than 1.5 mm during monitoring period, which has no impact on the stability of cliff. Deformation behavior provides the mutual duress and interaction between soil and engineering intervention. In addition, deformation mode attaches tensely to the damage pattern of the cliff. The conclusions are of importance to the stability evaluation of the carrier along Silk Road. 展开更多
关键词 endangered cliff CONSERVATION deformation behavior regression analysis modelling
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Computational analysis of linear friction welding process and micromechanical modeling of deformation behavior for medium carbon steel
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作者 杨夏炜 李文亚 马铁军 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3275-3281,共7页
Finite element simulation of linear friction welding(LFW) medium carbon steel was carried out using the ABAQUS software. A two-dimensional(2D) coupled thermo-mechanical model was established. First, the temperature fi... Finite element simulation of linear friction welding(LFW) medium carbon steel was carried out using the ABAQUS software. A two-dimensional(2D) coupled thermo-mechanical model was established. First, the temperature fields of medium carbon steel during LFW process were investigated. And then, the Mises stress and the 1st, 2nd and 3rd principal stresses fields' evolution of the steel during LFW process were studied. The deformation behavior of LFW carbon steel was analyzed by using micromechanics model based on ABAQUS with Python code. The Lode parameter was expressed using the Mohr stress circle and it was investigated in detail. 展开更多
关键词 linear friction welding finite element method deformation behavior micromechanics model
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Mechanical stress and deformation analyses of pressurized cylindrical shells based on a higher-order modeling
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作者 S.Mannani L.Collini M.Arefi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第2期24-33,共10页
In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoi... In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution. 展开更多
关键词 Principle of virtual work Thickness-stretched and shear deformable model Stress and strain analyses Cylindrical pressure vessel
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On Numerical Modelling of Industrial Powder Compaction Processes for Large Deformation of Endochronic Plasticity at Finite Strains
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作者 A R Khoei A Bakhshiani M Mofid 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期95-96,共2页
Compaction processes are one the most important par ts of powder forming technology. The main applications are focused on pieces for a utomotive, aeronautic, electric and electronic industries. The main goals of the c... Compaction processes are one the most important par ts of powder forming technology. The main applications are focused on pieces for a utomotive, aeronautic, electric and electronic industries. The main goals of the compaction processes are to obtain a compact with the geometrical requirements, without cracks, and with a uniform distribution of density. Design of such proc esses consist, essentially, in determine the sequence and relative displacements of die and punches in order to achieve such goals. A.B. Khoei presented a gener al framework for the finite element simulation of powder forming processes based on the following aspects; a large displacement formulation, centred on a total and updated Lagrangian formulation; an adaptive finite element strategy based on error estimates and automatic remeshing techniques; a cap model based on a hard ening rule in modelling of the highly non-linear behaviour of material; and the use of an efficient contact algorithm in the context of an interface element fo rmulation. In these references, the non-linear behaviour of powder was adequately desc ribed by the cap plasticity model. However, it suffers from a serious deficiency when the stress-point reaches a yield surface. In the flow theory of plasticit y, the transition from an elastic state to an elasto-plastic state appears more or less abruptly. For powder material it is very difficult to define the locati on of yield surface, because there is no distinct transition from elastic to ela stic-plastic behaviour. Results of experimental test on some hard met al powder show that the plastic effects were begun immediately upon loading. In such mater ials the domain of the yield surface would collapse to a point, so making the di rection of plastic increment indeterminate, because all directions are normal to a point. Thus, the classical plasticity theory cannot deal with such materials and an advanced constitutive theory is necessary. In the present paper, the constitutive equations of powder materials will be discussed via an endochronic theory of plasticity. This theory provides a unifi ed point of view to describe the elastic-plastic behaviour of material since it places no requirement for a yield surface and a ’loading function’ to disting uish between loading an unloading. Endochronic theory of plasticity has been app lied to a number of metallic materials, concrete and sand, but to the knowledge of authors, no numerical scheme of the model has been applied to powder material . In the present paper, a new approach is developed based on an endochronic rate independent, density-dependent plasticity model for describing the isothermal deformation behavior of metal powder at low homologous temperature. Although the concept of yield surface has not been explicitly assumed in endochronic theory, it is shown that the cone-cap plasticity yield surface (Fig.1), which is the m ost commonly used plasticity models for describing the behavior of powder materi al can be easily derived as a special case of the proposed endochronic theory. Fig.1 Trace of cone-cap yield function on the meridian pl ane for different relative density As large deformation is observed in powder compaction process, a hypoelastic-pl astic formulation is developed in the context of finite deformation plasticity. Constitutive equations are stated in unrotated frame of reference that greatly s implifies endochronic constitutive relation in finite plasticity. Constitutive e quations of the endochronic theory and their numerical integration are establish ed and procedures for determining material parameters of the model are demonstra ted. Finally, the numerical schemes are examined for efficiency in the model ling of a tip shaped component, as shown in Fig.2. Fig.2 A shaped tip component. a) Geometry, boundary conditio n and finite element mesh; b) density distribution at final stage of 展开更多
关键词 In On Numerical modelling of Industrial Powder Compaction Processes for Large deformation of Endochronic Plasticity at Finite Strains
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