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模空间可直分解的判定定理
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作者 王征平 刘永琴 《华中师范大学学报(自然科学版)》 CAS CSCD 北大核心 2000年第3期268-269,共2页
讨论了几类特殊模空间可直分解的判定条件 ,给出了有限维模的直和项和极大子模的关系以及有限维模的极大子模的生成形式 .
关键词 空间 直分解 生成系 有限维模 判定定理
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Finite element analysis of contact fatigue and bending fatigue of a theoretical assembling straight bevel gear pair 被引量:15
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作者 邓松 华林 +1 位作者 韩星会 黄松 《Journal of Central South University》 SCIE EI CAS 2013年第2期279-292,共14页
The aim of this work is to propose a 3D FE model of a theoretical assembling straight bevel gear pair to analyze the contact fatigue on the tooth surface and the bending fatigue in the tooth root. Based on the cumulat... The aim of this work is to propose a 3D FE model of a theoretical assembling straight bevel gear pair to analyze the contact fatigue on the tooth surface and the bending fatigue in the tooth root. Based on the cumulative fatigue criterion and the stress-life equation, the key meshing states of the gear pair were investigated for the contact fatigue and the bending fatigue. Then, the reliability of the proposed model was proved by comparing the calculation result with the simulation result. Further study was performed to analyze the variation of the contact fatigue stress and the bending fatigue stress under different loads. Furthermore, the roles of the driving pinion and the driven gear pair were evaluated in the fatigue life of the straight bevel gear pair and the main fatigue failure mode was determined for the significant gear. The results show that the fatigue failure of the driving pinion is the main fatigue failure for the straight bevel gear pair and the bending fatigue failure is the main fatigue failure for the driving pinion. 展开更多
关键词 straight bevel gear finite element method contact fatigue bending fatigue
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Modelling and simulation of contact force in cold rotary forging 被引量:2
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作者 秦训鹏 《Journal of Central South University》 SCIE EI CAS 2014年第1期35-42,共8页
Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve ... Cold rotary forging is an advanced and complex metal forming technology with continuous local plastic deformation.Investigating the contact force between the dies and the workpiece has a great significance to improve the life of the dies in cold rotary forging.The purpose of this work is to reveal the contact force responses in cold rotary forging through the modelling and simulation.For this purpose,a 3D elastic-plastic dynamic explicit FE model of cold rotary forging is developed using the FE code ABAQUS/Explicit.Through the modelling and simulation,the distribution and evolution of the contact force in cold rotary forging is investigated in detail.The experiment has been conducted and the validity of the 3D FE model of cold rotary forging has been verified.The results show that: 1) The contact force distribution is complex and exhibits an obvious non-uniform characteristic in the radial and circumferential directions; 2) The maximum contact force between the upper die and the workpiece is much larger than that between the lower die and the workpiece; 3) The contact force evolution history is periodic and every period experiences three different stages; 4) The total normal contact force is much larger than the total shear contact force at any given time. 展开更多
关键词 cold rotary forging metal forming SIMULATION contact force die life
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Numerical simulation of tire/soil interaction using a verified 3D finite element model 被引量:6
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作者 Namjoo Moslem Golbakhshi Hossein 《Journal of Central South University》 SCIE EI CAS 2014年第2期817-821,共5页
The compaction and stress generation on terrain were always investigated based on empirical approaches or testing methods for tire/soil interaction.However,the analysis should be performed for various tires and at dif... The compaction and stress generation on terrain were always investigated based on empirical approaches or testing methods for tire/soil interaction.However,the analysis should be performed for various tires and at different soil strengths.With the increasing capacity of numerical computers and simulation software,finite element modeling of tire/terrain interaction seems a good approach for predicting the effect of change on the parameters.In this work,an elaborated 3D model fully complianning with the geometry of radial tire 115/60R13 was established,using commercial code Solidwork Simulation.The hyper-elastic and incompressible rubber as tire main material was analyzed by Moony-Rivlin model.The Drucker-Prager yield criterion was used to model the soil compaction.Results show that the model realistically predicts the laboratory tests outputs of the modeled tire on the soft soil. 展开更多
关键词 tire/soil interaction finite element method(FEM) soil compaction stress distribution inflation pressure
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Effects of process parameters and die geometry on longitudinal welds quality in aluminum porthole die extrusion process 被引量:2
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作者 刘健 林高用 +2 位作者 冯迪 邹艳明 孙利平 《Journal of Central South University》 SCIE EI CAS 2010年第4期688-696,共9页
By using the rigid-visco-plasticity finite element method, the welding process of aluminum porthole die extrusion to form a tube was simulated based on Deform-3D software. The welding chamber height (H), back dimens... By using the rigid-visco-plasticity finite element method, the welding process of aluminum porthole die extrusion to form a tube was simulated based on Deform-3D software. The welding chamber height (H), back dimension of die leg (D), process velocity and initial billet temperature were used in FE simulations so as to determine the conditions in which better longitudinal welding quality can be obtained. According to K criterion, the local welding parameters such as welding pressure, effective stress and welding path length on the welding plane are linked to longitudinal welds quality. Simulation turns out that pressure-to-effective stress ratio (ρ/σ) and welding path length (L) are the key factors affecting the welding quality, Higher welding chamber best and sharper die leg give better welding quality. When H=10 mm and D=0.4 mm, the longitudinal welds have the best quality. Higher process velocity decreases welds quality. The proper velocity is 10 mm/s for this simulation. In a certain range, higher temperature is beneficial to the longitudinal welds. It is found that both 450 and 465℃ can satisfy the requirements of the longitudinal welds. 展开更多
关键词 aluminum alloy longitudinal welds porthole die die geometry extrusion process K criterion
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Three-dimensional finite element analysis on effects of tunnel construction on nearby pile foundation 被引量:6
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作者 杨敏 孙庆 +1 位作者 李卫超 马亢 《Journal of Central South University》 SCIE EI CAS 2011年第3期909-916,共8页
A three-dimensional finite element simulation was carried out to investigate the effects of tunnel construction on nearby pile foundation.The displacement controlled model (DCM) was used to simulate the tunneling-indu... A three-dimensional finite element simulation was carried out to investigate the effects of tunnel construction on nearby pile foundation.The displacement controlled model (DCM) was used to simulate the tunneling-induced volume loss effects.The numerical model was verified based on the results of a centrifuge test and a set of parametric studies was implemented based on this model.There is good agreement between the trend of the results of the centrifuge test and the present model.The results of parametric studies show that the tunnelling-induced pile internal force and deformation depend mainly on the pile?tunnel distance,the pile length to tunnel depth ratio and the volume loss.Two different zones are separated by a 45° line projected from the tunnel springline.Within the zone of influence,the pile is subjected to tensile force and large settlement;whereas outside the zone of influence,dragload and small settlement are induced.It is also established that the impact of tunnelling on a pile group is substantially smaller as compared with a single pile in the same location with the rear pile in a group,demonstrating a positive pile group effect. 展开更多
关键词 finite element analysis TUNNELLING pile foundation three-dimensional simulation displacement controlled model
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Nonlinear finite element analysis of effect of seismic waves on dynamic response of Shiziping dam 被引量:7
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作者 DING Xuan-ming LIU Han-long +1 位作者 YU Tao KONG Gang-qiang 《Journal of Central South University》 SCIE EI CAS 2013年第8期2323-2332,共10页
Many high earth-rockfill dams are constructed in the west of China. The seismic intensity at the dam site is usually very high, thus it is of great importance to ensure the safety of the dam in meizoseismal area. A 3D... Many high earth-rockfill dams are constructed in the west of China. The seismic intensity at the dam site is usually very high, thus it is of great importance to ensure the safety of the dam in meizoseismal area. A 3D FEM model is established to analyze the seismic responses of Shiziping earth-rockfill dam. The nonlinear elastic Duncan-Chang constitutive model and the equivalent viscoelastic constitutive model are used to simulate the static and dynamic stress strain relationships of the dam materials, respectively. Four groups of seismic waves are inputted from the top of the bedrock to analyze the dynamic responses of the dam. The numerical results show that the calculated dynamic magnification factors display a good consistency with the specification values. The site spectrum results in larger acceleration response than the specification spectrum. The analysis of relative dynamic displacement indicates that the displacement at the downstream side of the dam is larger than that at the upstream side. The displacement response reduces from the center of river valley to two banks. The displacement responses corresponding to the specification spectrum are a little smaller than those corresponding to the site spectrum. The analysis of shear stress indicates that a large shear stress area appears in the upstream overburden layer, where the shear stress caused by site waves is larger than that caused by specification waves. The analysis of dynamic principal stress indicates that the minimum dynamic stresses in corridor caused by specification and site waves have little difference. The maximum and minimum dynamic stresses are relatively large at two sides. The largest tensile stress occurs at two sides of the floor of grouting corridor, which may result in the crack near the corridor side. The numerical results present good consistency with the observation data of the grouting corridor in Wenchuan earthquake. 展开更多
关键词 finite element method earth-rockfill dam dynamic response acceleration response seismic wave
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Fluid-solid interaction of resistance loss of flexible hose in deep ocean mining 被引量:3
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作者 王志 饶秋华 刘少军 《Journal of Central South University》 SCIE EI CAS 2012年第11期3188-3193,共6页
The resistance loss of transportation was studied and the influences of buoyancy layout,mineral content and elastic modulus of flexible hose were investigated based on three-dimensional finite element model of fluid-s... The resistance loss of transportation was studied and the influences of buoyancy layout,mineral content and elastic modulus of flexible hose were investigated based on three-dimensional finite element model of fluid-solid interaction by MSC.MARC/MENTAT software.The numerical results show that the resistance losses increase with the increase of mineral content Cv and velocity of internal fluid v and decrease with the increase of elastic modulus E of flexible hose.The buoyancy layout and the velocity of internal fluid have greater impacts on the resistance losses than the elastic modulus of flexible hose.In order to reduce the resistance losses and improve the efficiency of the deep-ocean mining,Cv and v must be restricted in a suitable range (e.g.10%-25% and 2.5-4 m/s).Effective buoyancy layout (such as Scheme C and D) should be adopted and the suitable material of moderate E should be used for the flexible hose in deep-ocean mining. 展开更多
关键词 resistance loss flexible hose fluid-solid interaction deep-ocean mining finite element method
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Flexural response of reinforced concrete beams strengthened with post-poured ultra high toughness cementitious composites layer 被引量:6
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作者 王楠 徐世烺 《Journal of Central South University》 SCIE EI CAS 2011年第3期932-939,共8页
Four-point bending tests were conducted up to failure on eleven reinforced concrete (RC) beams and strengthening beams to study the effectiveness of externally pouring ultra high toughness cementitious composites (UHT... Four-point bending tests were conducted up to failure on eleven reinforced concrete (RC) beams and strengthening beams to study the effectiveness of externally pouring ultra high toughness cementitious composites (UHTCC) on improving the flexural behavior of existing RC beams.The strengthening materials included UHTCC and high strength grade concrete.The parameters,such as thickness and length of strengthening layer and reinforcement in post-poured layer,were analyzed.The flexural behavior,failure mode and crack propagation of composite beams were investigated.The test results show that the strengthening layer improves the cracking and ultimate load by increasing the cross section area.Introducing UHTCC material into strengthening not only improves the bearing capacity of the original specimens,but also disperses larger cracks in upper concrete into multiple tightly-spaced fine cracks,thus prolonging the appearance of harm surface cracks and increasing the durability of existing structures.Compared with post-poured concrete,UHTCC is more suitable for working together with reinforcement.The load?deflection plots obtained from three-dimensional finite-element model (FEM) analyses are compared with those obtained from the experimental results,and show close correlation. 展开更多
关键词 ultra high toughness cementitious composities strengthening beams flexural behavior post-poured layer
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Effect of cooling structure on thermal behavior of copper plates of slab continuous casting mold 被引量:2
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作者 孟祥宁 朱苗勇 《Journal of Central South University》 SCIE EI CAS 2013年第2期318-325,共8页
A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of... A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of hot surface is mainly governed by cooling structure and heat-transfer conditions. For hot surface centricity, maximum surface temperature promotions are 30 ℃and 15 ℃ with thickness increments of copper plates of 5 mm and nickel layers of 1 ram, respectively. The surface temperature without nickel layers is depressed by 10 ℃ when the depth increment of water slots is 2 mm and that with nickel layers adjacent to and away from mold outlet is depressed by 7℃ and 5 ℃, respectively. The specific trend of temperature distribution of transverse sections of copper plates is nearly free of cooling structure, but temperature is changed and its law is similar to the corresponding surface temperature. 展开更多
关键词 slab continuous casting MOLD copper plate cooling structure thermal behavior finite element analysis
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Numerical analysis on Joule heating of double-loop channel induction furnaces 被引量:1
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作者 赵涛 周孑民 +1 位作者 熊家政 李勇 《Journal of Central South University》 SCIE EI CAS 2009年第5期851-856,共6页
In order to investigate Joule heating power,a three-dimensional finite element model(FEM) was developed to predict Joule heating power in the channels of double-loop inductor. The simulated results were compared with ... In order to investigate Joule heating power,a three-dimensional finite element model(FEM) was developed to predict Joule heating power in the channels of double-loop inductor. The simulated results were compared with experimental data from low load trials for a 400 kW inductor. The results,such as power factor and Joule heating power,show reasonable correlation with experimental data,and Joule heating rate reaches the maximum at the corners and the minimum at the centre of the cross-section area. With increasing relative permeability of iron core,length of coils,current frequency and resistivity of metal melt,the power factor and Joule heating power change. It is concluded that current frequency,the resistivity and length of the coil play a critical role in determining the power factor and Joule heating power,whereas relative permeability of the magnetic core shows no significant influence on them. 展开更多
关键词 numerical simulation channel induction furnace Joule heating power factor
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Simulation of hydrogen diffusion in welded joint of X80 pipeline steel 被引量:2
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作者 严春妍 刘翠英 张根元 《Journal of Central South University》 SCIE EI CAS 2014年第12期4432-4437,共6页
Hydrogen diffusion coefficients of different regions in the welded joint of X80 pipeline steel were measured using the electro-chemical permeation technique. Using ABAQUS software, hydrogen diffusion in X80 pipeline s... Hydrogen diffusion coefficients of different regions in the welded joint of X80 pipeline steel were measured using the electro-chemical permeation technique. Using ABAQUS software, hydrogen diffusion in X80 pipeline steel welded joint was studied in consideration of the inhomogeneity of the welding zone, and temperature-dependent thermo-physical and mechanical properties of the metals. A three dimensional finite element model was developed and a coupled thermo-mechanical-diffusion analysis was performed. Hydrogen concentration distribution across the welded joint was obtained. It is found that the postweld residual hydrogen exhibits a non-uniform distribution across the welded joint. A maximum equivalent stress occurs in the immediate vicinity of the weld metal. The heat affected zone has the highest hydrogen concentration level, followed by the weld zone and the base metal.Simulation results are well consistent with theoretical analysis. 展开更多
关键词 numerical simulation hydrogen diffusion temperature field stress field
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Application of 1D/3D finite elements coupling for structural nonlinear analysis 被引量:13
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作者 岳健广 A.Fafitis +1 位作者 钱江 雷拓 《Journal of Central South University》 SCIE EI CAS 2011年第3期889-897,共9页
An element coupling model (ECM) method was proposed to simulate the global behavior and local damage of a structure.In order to reflect the local damage and improve the computational efficiency,three-dimensional (3D) ... An element coupling model (ECM) method was proposed to simulate the global behavior and local damage of a structure.In order to reflect the local damage and improve the computational efficiency,three-dimensional (3D) solid elements and one-dimensional (1D) beam element were coupled by the multi-point constraint equations.A reduced scale 1?8 model test was simulated by the ECM and a full three dimensional model (3DM) contrastively.The results show that the global behavior and local damages of ECM agree well with the test and 3DM.It is indicated that the proposed method can be used in the structural nonlinear analysis accurately and efficiently. 展开更多
关键词 elements coupling model global behavior local damage multi-point constraint equations nonlinear analysis
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Numerical analysis on thermal regime in double-loop channel inductor
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作者 赵涛 欧少端 +1 位作者 周孑民 熊家政 《Journal of Central South University》 SCIE EI CAS 2010年第1期180-186,共7页
In order to investigate the temperature distribution, a three-dimensional finite element model (FEM) was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated result... In order to investigate the temperature distribution, a three-dimensional finite element model (FEM) was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated results were compared with experimental data from low load trials of a 400 kW inductor. The results of numerical simulations, such as the temperature and Joule heating rate, show reasonable correlation with experimental data. The results indicate that Joule heating rate and the temperature reach the maximum at the comers and the minimum at the centre of the cross-section area. The temperature difference between the inlet and outlet is in an inverse proportion to mass transport. Joule heating rate and the temperature are directly proportional to power frequency. It is concluded that mass transport and power frequency play a critical role in determining the temperature regime and Joule heating rate, the relative permeability of the magnetic core shows no significant influence on temperature regime and Joule heating rate, when the relative permeability varies from 5 000 to 10 000. 展开更多
关键词 numerical simulation INDUCTOR finite element method Joule heating rate
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