Finite Element Numerical Calculation Research Articles

Fracture prediction of electromagnetic silicon steel in reheating furnace

ABSTRACTThis article proposes the use of strain energy density (SED) for the prediction of fracturing in silicon steel slabs undergoing reheating in a furnace. Reheating is commonly used to soften steel before hot rolling into ultra-thin silicon steel sheets referred to as electromagnetic steel. High heating rates are required to reduce the time spent in the reheating furnace to increase the efficiency of producing ultra-thin electromagnetic steel sheets and decrease fuel consumption. However, an excessive increase in heating rates may induce fracturing due to the comparatively brittle nature of the silicon used in electromagnetic steel slabs to enhance the electromagnetic properties. In this study, the authors used finite element numerical calculation to elucidate the fracture mechanism of electromagnetic steel slabs undergoing heating. The authors then used SED as a criterion by which to optimize the heating rates without inducing fracturing in electromagnetic steel. The proposed model could be used as a guide to shorten the time required for heating various types of steel in reheating furnaces.

Research and design of doubly salient permanent magnet motor for hybrid electric vehicle based on the NdFeB permanent magnet material

The performance of hybrid electric vehicle motor directly affects its power performance and fuel economy. The high performance sintered NdFeB permanent magnet material is chosen as the core material of the hybrid vehicle motor for the design of the permanent magnet in this paper, and its size is also determined. A doubly salient permanent magnet motor is proposed here on the basis of the selected NdFeB permanent magnet material, and its structure size is designed. The finite element numerical calculation is carried out for the motor in particular rotor position angle on the basis of the field quantity to obtain the magnetic field distribution law in several typical rotor positions and the static characterise parameters of the motor are further obtained. Final, inspect the performance of the prototype objectively based on the bench experiment of the designed physical prototype, and the prototype experiment and finite element results both proved that the designed doubly salient permanent magnet motor could meet the requirements of hybrid electric vehicle, so as to achieve the purpose of the research and design of the doubly salient permanent magnet motor used in hybrid electric vehicle.

Wear predictions for cams in line contacts based on multidisciplinary simulation

Purpose – This paper aims to present the model and method involving multi-body system dynamic analysis, finite element quasi-statics contact analysis and numerical calculation of elastohydrodynamic lubrication (EHL), according to the cam wear prediction using Archard’s model. Cam–follower kinematic pairs always work under wear because of concentrated contacts. Given that a cam and follower contact often operates in the mixed or boundary lubrication regime, simulation of cam wear is a multidisciplinary problem including kinematic considerations, dynamic load and stress calculations and elastohydrodynamic film thickness evaluations. Design/methodology/approach – Multi-body system dynamic analysis, finite element quasi-statics contact analysis and numerical calculation of EHL are applied to obtain the dynamic loads, the time histories of contact pressure and the oil film thicknesses in cam–follower conjunctions to predict cam wear quantitatively. Findings – The wear depth of the cam in the valve train of a heavy-load diesel engine is calculated, which is in good agreement with the measured value in the practical test. The results show that the cam–tappet pair operates under a mixed lubrication or boundary lubrication, and the wear depths on both sides of the cam nose are extremely great. The wear of these points can be decreased significantly by modifying the local cam profile to enlarge the radii of curvature. Originality/value – The main value of this work lies in the model and method involving multi-body system dynamic analysis, finite element quasi-statics contact analysis and numerical calculation of EHL, which can give good prediction for the wear of cam.

Finite Element Method Using a Characteristic-Based Split for Numerical Simulation of a Carbonate Fracture-Cave Reservoir

Fracture-cave carbonate reservoirs occur widely in source rocks and are prospects for exploitation worldwide. However, the presence of massive caves and multiscale fracture systems results in extremely complex fluid flow patterns. Therefore, in this paper, a discrete network model for fracture-cave reservoirs was established to study fluid flow characteristics and pressure distributions in complex flow regimes. In this study, the cave system was treated as a free-flow region, and the fluid flow in fracture systems followed the Navier-Stokes and Darcy equations, respectively. After discrete modeling, the Galerkin finite element method was used for numerical calculation of the single-phase free flow; the method maintains a high-precision result with low grid orientations during the simulation. In addition, because only one linear equation requires solving at each step, the solution is obtained quickly. Moreover, based on the proposed discrete media network model of fracture-cave reservoirs and the finite element numerical calculation method, a corresponding simulator was also developed. The finite element numerical simulation method based on the characteristic-based split (CBS) algorithm has proven to be applicable to complex flow problems in fracture-cave reservoirs.

Metal-free and non-fluorine paper-based generator

Paper-based generator which can be integrated into traditional paper packaging process flows is particularly desirable. In this study, we reported a novel metal-free, non-fluorine, foldable paper-based electret generator based on electrostatic effect. The power generating process was carefully studied by a finite element simulation and numerical calculation in this report. The paper-based generator stimulated by human motion could drive a commercial liquid crystal display (LCD), showing its potential application in anti-counterfeit label. Moreover, a multiple-fold paper-based generator was also fabricated, and the enhancement of the area output is demonstrated. Therefore, the paper-based electret generator can effectively accumulate the irregular energy and extend the applications for paper electronics.

The Numerical Calculation Based on ABAQUS of Lattice Type Steel Sheet Pile Wharf Structure

This paper uses the world universal finite element software ABAQUS to establish a finite element numerical calculation model of the structure of lattice type steel sheet pile. for the same condition of different soil depth of design elements of lattice type steel sheet pile wharf structure, calculation and analysis of the calculation results and research get the relevant conclusions for reference.

Investigations on vibration characteristics of two-layered piezoceramic disks

This paper investigates the transverse and planar vibration characteristics of two-layered piezoceramic disks for traction-free boundary conditions by theoretical analysis, finite element numerical calculation, and experimental measurements. Amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI), laser Doppler vibrometer (LDV), and impedance analysis were used to perform measurements and verify the theoretical solutions for extensional, tangential, and transverse vibrations. The poling direction of piezoelectric elements determines whether they are denoted as either of series- or parallel-type. This study observed that the resonant frequencies and mode shapes of the series- and parallel-type piezoceramic disks present different dynamic characteristics in resonance. Planar and transverse vibrations are coupled in series-type piezoceramic disks and uncoupled in those of parallel-type. Good agreements of dynamic characteristics determined by theoretical analysis, experimental measurements, and numerical calculation are presented for series- and parallel-type piezoceramic disks.

Stability of Liangshuijing landslide under variation water levels of Three Gorges Reservoir

Three Gorges Reservoir area of Yangtze River in China is a geological disaster-prone zone with frequent landslides. Liangshuijing landslide in Yunyang County in this area is just a case. The impoundment water level of Three Gorges Reservoir was 135 m in 2003, 156 m in 2006 and reached 175 m in 2009. The effect of such a large variation of reservoir level on the deformation and stability of Liangshuijing landslide is not negligible. It once suffered from a dangerous situation due to the influences of various factors such as water level variation and rainfall. Based on the geological exploration, a thorough analysis of the deformation status and geological engineering situation of Liangshuijing landslide is made, and the formation and instability mode of the landslide are also judged. Based on the limit equilibrium analysis method, the stability of axial profile of the landslide is studied under three kinds of extreme conditions (impoundment water level of 145, 175 m and drawdown of 175–145 m). Three-dimensional finite element numerical calculation is then adopted to study the deformation of the landslide under the above conditions based on the hydro-mechanical coupling numerical model. The quantitative calculations reveal that the variation of groundwater level caused by the variation of reservoir level is the main factor for the landslide resurrection, especially under the third condition of rapid drawdown. It is recommended to continue monitoring the landslide so as to further understand the deformation trend of the landslide under the influences of water storage.

Numerical Calculation of Soil Pressure inside the Lattice Type Steel Sheet Pile Wharf Structure

Lattice type steel sheet pile wharf is a new type of wharf structure, which is increasingly and widely used, but its structure is complicated, and the calculation theory is not perfect. This paper uses the general finite element software ABAQUS to establish the finite element numerical calculation model of grid shape steel sheet pile structure. The result was deeply researched and analysed,so some useful conclusions are drawn that can be used as references in the engineering application.

Structure Optimization and Welding Residual Stress Analysis of Twin-Web Turbine Disc

This paper has proposed a new shape of the twin-web turbine disc. Based on a design optimization of the shape of the twin-web turbine disc by finite element numerical calculation, we analyzed welding types and carried out the simulation of the welding process and obtained the residual stress. Finally we got a 5.8% weight loss and summarized residual stress of the welding and proved the feasibility of the new shape.

Influence Analysis of the Magnetic Properties of the Materials on the Magnetic Powder Clutch Characteristics

The torque transmission capacity within a range of the structure is the main factor that limit the application of the magnetic powder clutch in the vehicle transmission field. In order to increase the torque transmitting characteristics of the magnetic powder clutch, the analysis model of the magnetic powder clutch was established with finite element numerical calculation method based on the depth analysis its operating principle, which focused on the study of the influence of the magnetic property of the magnetic powder and magnetic circuit material on the magnetic powder clutch performance. The research results showed that the greater of the saturated magnetic induction and the magnetic permeability of the magnetic powder and magnetic circuit material are, the better of the torque transmitting characteristics of the magnetic powder clutch is.

Dynamics Study and Damping Optimization of Circular Saw Based on Numerical Simulation and Experimental Analysis

Serious vibration and noise exists in the circular saw cutting process. In order to reduce the cutting vibration and noise, this paper uses the finite element numerical calculation and modal testing analysis to study the dynamic characteristics of the circular saw blades, obtain the circular saw’s kinetic parameters, such as each order natural frequency, the main vibration mode and damping ratio, evaluate the circular saw system’s dynamic response. Through the optimization of slotted design and experimental analysis, a circular saw with reasonable structure reduces the maximum vibration displacement of 11.1% which increases the circular saw blades cutting quality, prolongs the service life and reduces the cutting noise.

Investigation of Relationship between Instrumented Indentation Nominal Hardness and Reduced Elastic Modulus with Large Apex Angle Indenter

Based on dimensional analysis, finite element numerical calculation is undertaken on elastic–plastic solids to investigate the relationship between instrumented indentation nominal hardness Hn and reduced elastic modulus Er for three different apex angle indenters. The half-included angles of axisymetric conical indenter models are 62.9°, 70.3°and 85.566° which are corresponding to the real indenters of cube corner indenter with 60° face angle, Berkovich indenter with 65.27° face angle and cube corner indenter with 85° face angle, respectively. The relationship between a nominal hardness/reduced elastic modulus (Hn/Er) and elastic work/total indentation work (We/Wt) is established with a sixth-order polynomial form for each apex angle indenter. For rigid indenter of instrumented indentation model, reduced elastic modulus Er=1/[(1+v2)/E], where E and v are elastic modulus and Poisson’s ratio of the indented material. Therefore, Hn/Er–We/Wt relationship can be used to give estimates of E. Accuracy estimation for the each relationship of each half-included angle indenter shows that the large half-included angle of 85.566° gives better Er measurement error of +11.56% for a low yield strength material(e.g., materials for which σy=100MPa, n=0 and E=200GPa), while for the smaller half-included angle of 62.9° or 70.3° indenter, the measurement error is > ±12.74%. The research in this paper confirms that Hn/Er–We/Wt relationship of large apex angle indenter such as 85.566° half-included angle is recommended to be used for estimating the elastic modulus E of indented material.

Detent Force Modeling and Analysis for Vertical Permanent-Magnet Linear Synchronous Motor Using Equivalent Magnetic Network Method

This paper investigates the detent force modeling of a slotted iron core type vertical permanent magnet linear synchronous motor (PMLSM) for ropeless elevator applications. Variable network non-linear magnetic equivalent circuit model is established to predict the detent force of PMLSM. The topology structure of equivalent magnetic circuit is developed and the permeances are derived and calculated. The end effect of two end teeth is essential for analysis of detent force and it is focused in the modeling. Magnetic saturation of primary iron-core also be taken into account. In final some 3-D finite-element numerical calculation results are used to validate the feasibility of the proposed method.

Optimize the Structure of Air Sparger for Stirred Bioreactor

During the whole process of cell culture, it needs enough air, especially oxygen supply. Therefore, the research about air sparger became significant. There are many influence factors of air sparger are important, including air sparger structure, installation location, ventilation rate. In order to solve these problems, the finite element numerical calculation is used to set a numerical model of air-liquid two-phase flow. This analysis makes clear that the distance between air vent and the bottom of bioreactor has little effect on the air voids, and the air voids is higher by adopting the structure of single air vent compared with the one of distribution ring structure. But the ventilation structure of big distribution ring avoids flooding effectively. The air voids of bioreactor increased with the velocity of ventilation is increased within limits. However, it causes air incomplete dispersion in bioreactor, overflowing from head top of the liquid, flooding and low air voids, if the ventilation velocity is over speed.

Application Analysis of an Improved N-R Iterative Method about Finite Element Numerical Calculation

During the numerical calculation by FE (Finite Element) method, N-R (Newton-Raphson) iterative method will be used to solve the problem such that material performing with elasto-plastic character and geometric non-linearity. However, if the problem has macro scale DOFs (degree of freedom), the classical N-R method is shown to make a low efficiency on the whole process. For this reason, in this paper, an improved N-R iterative method is proposed by creating proper mandatory limiters to change the step size of displacement field increment. In this way, the size of single iterative step is enlarged in the new method with tangent stiffness matrix used as classical N-R iterative theory as well. Furthermore, to test stability of the new method, two models of structure are chosen to be calculated with this method. In the conclusion, the improved N-R iterative method is indicated to be an efficient and stable numerical method which could solve nonlinear problems, especially with macro scale DOFs.

C型固体电枢3维有限元电磁发射计算

C型固体电枢3维有限元电磁发射计算

Structural Design and Force Analysis for Equatorial Diagnostic Port Plug of ITER

The structural design of equatorial diagnostic port plug for international thermonuclear experimental reactor (ITER) was discussed in this paper. The induced electromagnetic (EM) loads of port plug and blanket shielding module (BSM) were presented. The finite element analysis (FEA) and numerical calculation of the system were performed under the maximum loads. According to the American Society of Mechanical Engineers (ASME) criteria, the EM stress is far below the admissible failure boundary, which indicates that the system can resist the cooperative action of EM loads and device deadweight. The analysis could provide technical data and references for further analysis and optimized design of the system.

Numerical simulation of fatigue life prediction of pressure vessel based on cyclic J-integral

A numerical simulation technology of fatigue life prediction of pressure vessel based on cyclic J-integral is de- veloped.Through finite element numerical calculation and experiment test on pressure vessel containing inner portrait surface crack,the results show that initia ellipse surface crack tends to round surface crack gradually during fatigue develop- ing and keeps the round shape to develop.The velocity of crack fatigue development is not uniform and presents the trend of more quickly.The numerical simulation results of fatigue life prediction based onΔJ have higher precision than those ofΔK based and satisfy the engineering requirement.This technology have important application value for fatigue life prediction of pressure vessel in use containing defects.

Visualization simulations for a cold press die

The detailed description of mechanical characteristics and their influence on sheet forming is discussed. This paper introduces the key problems in such as finite element numerical calculation and visualization simulation for a pressing die to realize visualization simulation for a cold press die. Combined with this problem, the paper does describe useful exploration of guiding press die design using visualization simulation.