COUPLED SIMULATION OF 3D ELECTRO-MAGNETO-FLOW FIELD IN HALL-HEROULT CELLS USING FINITE ELEMENT METHOD

Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.

Numerical Simulation of Projection Welding Processes for Door Hinge of Automobile Based on Coupled Fields Analysis

Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.

Simulation study of coupled particle cascade and finite element analysis for beam dump of DALS

Purpose Charged particle cascade simulations,in conjunction with finite element thermal and mechanical calculations,are essential for addressing engineering challenges associated with the design of accelerator beam dumps.This study aims to investigate the integration of the FLUKA Monte Carlo program and the COMSOL finite element program as indispensable tools in the development of advanced models for spatial energy deposition distributions,temperature assessments,and stress analysis within the DALS beam dump.Methods The paper delves into aspects of model development,data transfer,and practical applications,focusing on the successful coupling of FLUKA Monte Carlo simulations with COMSOL finite element analyses.Tens of millions of elements were created and utilized to estimate spatial energy deposition distributions,assess temperatures,and analyze stresses within the critical absorber of the DALS beam dump.The study comprehensively analyzes the process from the impact of high-energy electron beam on the beam dump to the spatial distribution of energy deposition,providing input for subsequent thermal and structural analyses.Results The successful coupling of FLUKA and COMSOL enabled the calculation of spatial temperature distributions and structural analyses of the absorber within the DALS beam dump.The utilization of tens of millions of defined bins ensured seamless data transfer from the particle cascade simulation to finite element analysis,guaranteeing high resolution and accuracy in the calculations.The results provide valuable insights into the thermal and mechanical behavior of the beam dump absorber,a critical safety component in accelerator systems.Conclusions The study demonstrates that the integration of FLUKA Monte Carlo simulations with COMSOL finite element analyses is a dependable and efficient tool for addressing real-world engineering challenges,particularly those related to the design of beam dumps in accelerator systems with charged particle beams.The advanced analytical approach provides crucial information for the optimal design and safety assessment of accelerator components.

Thermal-electrical Coupled Analysis and Experimental Investigation on Spark Plasma Sintering of SiC Ceramics

Finite element simulations were conducted to study the mechanism of spark plasma sintering. The spark plasma sintering of SiC ceramics was simulated by the Marc software based on the load current curve and temperature-time curve deserved by SPS experiment. The concept of equivalent radiation coefficient was presented and applied during the simulation. The temperature distribution regularity of SiC ceramics sintered by SPS technology was got by thermal-electrical coupled finite element simulation. The experimental results show that by thermal-electrical coupled finite element analysis, the temperature rising and distribution regularity of nonconductive material can be preferable forecasted in the sintering process of SPS. In the initial stage of the heat preservation, the temperature of the central part of the sample has achieved sintering temperature, but now, the temperature of the sample is not uniform. The temperature for each part of the die is also quite different and the sample temperature in the center is higher than that in the edge. In the end of heat preservation, the central temperature of the sample is 50 ℃higher than the required sintering temperature, and the temperature gap for each part of the die decreases gradually.

Different discretization method used in coupled water and heat transport mode for soil under freezing conditions

A coupled water and heat transport mode is established based on the Richards equation to study water flow and heat transport in soil during freezing process. Both the finite difference and finite element method are used in the discretization, respectively. Two different computer programs are written and used to simulate an indoor unidirectional frozen test. The freezing depth, freezing rate and temperature variation are compared among lab tests, finite difference calculation simulation and finite element calculation simulation. Result shows that： the finite difference method has a better performance in freezing depth simulation while the finite element method has a better performance in numerical stability in one-dimensional freezing simulation.

Research on Simulation Methods of Electric Field Intensity on Surface of 10 kV Cable Joint

The electric field intensity (EFI) is important characteristic quantity for evaluating the internal insulation state of cable joints. Based on finite element method, this paper proposes two EFI research methods, field-circuit coupling method and equivalent circuit method. The average EFI of the inner surface of the outer semi-conducting shield can be calculated from the current in the measuring circuit. The relative error between these two methods is about 15%, which roughly proves the consistency of the two methods. Further practical application research enables online monitoring of cable joints.

Coupled Vibration Analysis of Vehicle-Bridge System Based on Multi-Boby Dynamics

For establishing the refined numerical simulation model for coupled vibration between vehicle and bridge, the refined three-dimensional vehicle model is setup by multi-body system dynamics method, and finite element method of dynamic model is adopted to model the bridge. Taking Yujiang River Bridge on Nanning-Guangzhou railway line in China as study background, the?refined numerical simulation model of whole vehicle and whole bridge system for coupled vibration analysis is set up. The dynamic analysis model of the cable-stayed bridge is established by finite element method, and the natural vibration properties of the bridge are analyzed. The German ICE Electric Multiple Unit (EMU) train refined three-dimensional space vehicle model is set up by multi-system dynamics software SIMPACK, and the multiple non-linear properties are considered. The space vibration responses are calculated by co-simulation based on multi-body system dynamics and finite element method when the ICE EMU train passes the long span cable-stayed bridge at different speeds. In order to test if the bridge has the sufficient lateral or vertical rigidity and the operation stability is fine. The calculation results show: The operation safety can be guaranteed, and comfort?index is “excellent”. The bridge has sufficient rigidity, and vibration is in good condition.

Kinematics of Convergence and Deformation in Luzon Island and Adjacent Sea Areas: 2-D Finite-Element Simulation

The Luzon Island is a volcanic arc sandwiched by the eastward subducting South China Sea and the northwestward subducting Philippine Sea plate. Through experiments of plane-stress, elastic, and 2-dimensional finite-element modeling, we evaluated the relationship between plate kinematics and present-day deformation of Luzon Island and adjacent sea areas. The concept of coupling rate was applied to define the boundary velocities along the subduction zones. The distribution of velocity fields calculated in our models was compared with the velocity field revealed by recent geodetic （GPS） observations. The best model was obtained that accounts for the observed velocity field within the limits of acceptable mechanical parameters and reasonable boundary conditions. Sensitivity of the selection of parameters and boundary conditions were evaluated. The model is sensitive to the direction of convergence between the South China Sea and the Philippine Sea plates, and to different coupling rates in the Manila trench, Philippine trench and eastern Luzon trough. We suggest that a change of ±15° of the direction of motion of the Philippine Sea plate can induce important changes in the distribution of the computed displacement trajectories, and the movement of the Philippine Sea plate toward azimuth 330° best explains the velocity pattern observed in Luzon Island. In addition, through sensitivity analysis we conclude that the coupling rate in the Manila trench is much smaller compared with the rates in the eastern Luzon trough and the Philippine trench. This indicates that a significant part of momentum of the Philippine Sea plate motion has been absorbed by the Manila trench; whereas, a part of the momentum has been transmitted into Luzon Island through the eastern Luzon trough and the Philippine trench.

基于Simulink和Ansys Icepak的单相智能物联电能表计量单元电热耦合仿真方法研究

智能物联电能表是一种复杂的电子系统,其计量精度会受到温度、负载、元器件参数等多种因素的影响,单纯的热模型无法满足对其仿真的精度要求。以某主流智能物联电能表为例,通过分析其模块原理,构建考虑温度影响的智能物联电能表计量单元电热间接耦合仿真模型,得到不同环境温度下智能物联电能表的温度场。经实验测定,电热耦合仿真比单独的热仿真的精度水平更高,仿真数据与实测数据间最大误差为2.2%,仿真精度较好。

Thermo-hydro-mechanical modeling of fault discontinuities using zero-thickness interface element

In this paper,a coupled thermo-hydro-mechanical(THM)simulation in a faulted deformable porous medium is presented.This model involves solving the mass conservation,linear momentum balance,and energy balance equations which are derived from the Biot’s consolidation theory.Fluid pore pressure,solid displacement,and temperature are chosen as initial variables in these equations,and the finite element method in combination with the interface element is used for spatial discretization of continuous and discontinuities(fault)parts of the medium to solve the equations.The main purpose of this study is providing precise formulations,applicability,and ability of the triple-node zero-thickness interface element in THM modeling of faults.It should be noted that the system of equations is solved using a computer code written in Matlab program.In order to verify the developed method,simulations of index problems such as Mandel’s problem,and coupled modeling of a faulted porous medium and a faulted aquifer are presented.The modeling results obtained from the developed method show a very good agreement with those by other modeling methods,which indicates its accuracy.

高压陶瓷电容特性及在配网柱上开关的应用研究

电压传感器是深度融合型柱上开关的关键器件,其自身直接承受电压载荷,是深度融合柱上开关产品开发成败的关键。以无机物介质为载体的高压陶瓷电容器,具有体积小、容量大、寿命长的特点,尤其契合深度融合型固封极柱的结构特点和应用场景。文中首先分析了陶瓷电容器件特性,再结合深度融合柱上开关产品的具体应用场景,开发了基于高压陶瓷电容器的一二次融合柱上开关产品;相关研究表明,高压陶瓷电容器在配网领域应用具有相当潜力。

不同载荷作用下膜片厚度对风电联轴器性能的影响

为研究膜片厚度对风电联轴器传递转矩及不对中补偿性能的影响,建立了联轴器整体有限元模型,得到了转矩、轴向位移及角位移载荷共同作用下的膜片应力云图,结合膜片实际破坏位置,验证了有限元仿真分析的可行性;给出了不同载荷作用下各膜片厚度的应力响应,分析了不同载荷对各厚度膜片应力的影响程度,探讨了不同厚度下膜片组螺栓预紧力及接触摩擦因数对联轴器性能的影响。结果表明,膜片厚度的增加能够提高联轴器传递转矩能力,但会削弱其不对中补偿能力;各载荷对不同厚度膜片应力影响的主导程度不同,膜片厚度为3 mm时的联轴器综合性能最强;螺栓预紧力对联轴器性能的影响很大,而膜片间的接触摩擦因数对联轴器性能的影响较小。

COMSOL仿真模拟埋地天然气管道多孔瞬态泄漏与扩散

为研究埋地天然气管道多个泄漏孔下的扩散规律,以多孔介质中埋地管道的泄漏孔个数、泄漏孔间距、管道埋深为变量研究流体运输扩散现象.使用COMSOL软件构建三维模型,基于多孔介质中气体扩散物理模型,设置土壤域为多孔介质域观察管道非稳态过程泄漏扩散现象,并采用有限元法模拟多物理场耦合作用.结果表明:土壤域内多个泄漏孔释放的甲烷气体达到饱和时间比单孔泄漏约缩短120min;泄漏孔间距为300mm比间距为100mm时形成土壤表面危险半径约增加1.5倍;埋地管道上方覆土厚度与固定时间内土壤表面气体浓度变化呈负相关;泄漏孔个数和孔径的增加与土壤内甲烷含量变化呈正相关.研究结果可为天然气泄漏事件应急预案的制定提供技术支持.

C型钢缀板柱的有限元模拟方法研究

缀板柱以其制造简便、稳定性高且价格低廉的优势,在工程钢结构中得到了广泛应用,如何准确模拟缀板与立柱之间的连接情况,是工程结构有限元模拟时的重要问题。文章采用有限元软件ANSYS,研究C型钢缀板柱中缀板与立柱之间连接情况的有限元模拟问题,通过对比单元整体建模与节点耦合建模的模拟结果,分析了节点耦合连接方法的模拟原理并提出了使用时的注意事项。计算分析表明:整体建模模拟效果较好但不便于模型修改和精细化模拟,节点耦合便于修改但需要考虑耦合方法和连接面积。文章提出的简化统一耦合方法模拟效果好,适应性强,对于工程实践中的有限元模拟工作具有一定指导意义。

某小口径火炮弹丸挤进过程动力学特性分析

为研究某小口径火炮不同坡膛结构下弹丸挤进过程的动力学特性,建立了考虑挤进阻力变化的内弹道方程组并通过vuamp子程序引入到有限元求解中,实现了挤进过程中内弹道计算与弹丸挤进有限元仿真耦合求解。通过对弹丸全膛运动的仿真分析验证了模型的可行性,随后得到并分析不同坡膛锥度、膛线深度及阴线宽度下挤进过程中弹丸的速度、加速度、挤进阻力和膛压曲线及变化影响规律。结果表明,坡膛锥度对挤进过程中弹丸的动力学参数影响不是单调的,而膛线深度及阴线宽度的改变则单调地影响弹丸动力学参数,对优化坡膛结构及弹带设计具有一定的指导意义。

多胞子弹冲击泡沫夹芯梁的动力学响应分析

为了研究均匀/梯度多胞子弹冲击泡沫夹芯梁的耦合响应过程和多胞子弹对夹芯梁的加载效果,对该冲击过程开展了理论分析、数值模拟和试验研究:通过将泡沫夹芯梁等效为单梁以简化分析,基于多胞子弹的冲击波模型和泡沫夹芯梁的等效单梁响应模型,构建了多胞子弹冲击泡沫夹芯梁的耦合分析模型,给出了冲击过程中各响应阶段的控制方程,并结合龙格-库塔方法对方程进行了数值求解;基于三维Voronoi技术,开展了均匀/梯度多胞子弹冲击泡沫夹芯梁的细观有限元模拟;在多胞子弹的冲击测试平台上进行了试验研究,结合高速摄影技术获取了多胞子弹和泡沫夹芯梁的速度响应。结果表明:耦合分析模型可以准确地预测多胞子弹和泡沫夹芯梁的速度历程曲线以及多胞子弹产生的冲击压强;在初始动量相同但密度分布或初速度不同的多胞子弹冲击下,同一构型的泡沫夹芯梁展现出不同的力学响应,这说明多胞子弹的加载不能简单地等效为脉冲加载,多胞子弹与夹芯梁之间的耦合效应不可忽略;相较于均匀多胞子弹,梯度多胞子弹的冲击压力波形更加尖锐,在其衰减过程中展现出更强的非线性特征。

基于4H-SiC的开槽四梁式压阻式加速度计设计及仿真研究

基于4H-SiC设计了一种开槽四梁式的压阻式加速度计,通过分析开槽位置、开槽大小对传感器灵敏度及固有频率的影响确定了开槽的相关参数,并对该结构采用有限元方法进行了热-力耦合仿真,确定了该结构在不同温度场下施加不同载荷时的理论电压输出。研究结果表明:该结构相较于传统双端四梁结构输出灵敏度提升51.4%,固有频率仅下降14.2%,在ANSYS 600℃的稳态温度场环境下,传感器输入载荷与输出电压成线性关系,理论满量程输出为39.71 mV。

基于4H-SiC的低横向灵敏度压阻式加速度计设计仿真研究

文中基于4H-SiC设计了一种开槽式低横向灵敏度压阻式加速度计,通过分析支撑梁位置及开槽尺寸对加速度计性能的影响确定了相关结构参数,并对该结构采用有限元方法进行了热-力耦合仿真,确定了该结构在600℃温度场中施加不同载荷时的理论电压输出。研究结果表明:该结构相较于已有的双端四梁结构X轴方向的横向灵敏度由3.3%降至2.6%,Y轴方向横向灵敏度由29.9%降至1.5%,传感器芯片在600℃高温环境下输入载荷与输出电压呈线性关系,100 g载荷下的理论输出电压为3.65 mV。

PQF连轧过程轧件三向应力有限元分析

为提高无缝钢管产品质量,依据实际连轧生产工艺,基于Abaqus软件建立5机架PQF连轧三维热力耦合有限元模型,结合连轧过程的特点对模拟结果进行了分析。结果表明,受各道次轧辊位置、变形量、轧制速度等工艺参数的影响,连轧时孔型顶部和辊缝处的径向、周向、轴向应力分布状态并不相同,管内、外表面的轴向应力状态也有差异。进一步对相应规律进行了总结,并讨论了各向应力产生变化的原因及其影响。荒管尺寸参数和轧制力的模拟结果与实测结果相吻合,验证了模型的可靠性。研究结果对连轧过程相关工艺的设计与优化具有参考价值。

径向磁液轴承定子温升及热变形研究

提出一种新型的磁液轴承,以电磁悬浮支承为主、静压支承为辅,实现双重支承,并可以实时调控。通过建立磁液轴承的有限元分析模型,对其进行流-固-热耦合求解,得到轴承的流场、温度、应力及应变分布云图。通过调整轴承系统的结构参数(进油孔直径和线圈匝数)及运行参数(输入电流、进油流量、转子转速)分别进行有限元建模,利用ANSYS软件进行仿真分析,求解不同参数对轴承温升及定子热变形的影响规律。结果表明:流体造成的压力在进油孔内最高为1 MPa,流体在油膜处流速最高为0.8 m/s;轴承定子温度分布对称,有利于散热。研究结果为磁液轴承系统的优化设计提供理论依据。