• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.25-27
• /
• 1998

In this paper electromagnetic force and its distribution are analyzed on the nonlinear magnetic materials by Finite Element Method. Most of magnetic materials have the nonlinear characteristic, which considerably effects on the magnetic system. And it is necessary to know its distribution at the every Part of the magnetic material in order to design the, magnetic system considering noise, vibration and strain characteristic. The results are obtained by Maxwell stress. virtual work and magnetic charge method and compared with one another.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.16 no.3
• /
• pp.181-192
• /
• 2012

Here in this paper, the steady paint film flow on a vertical wall of a non-Newtonian pseudo plastic fluid for drainage problem has been investigated. The exact solution of the nonlinear problem is obtained for the velocity profile. Also the average velocity, volume flux, shear stress on the wall, force to hold the wall in position and normal stress difference have been derived. We retrieve Newtonian case, when material constant ${\mu}_1$ and relaxation time ${\lambda}_1$ equal zero. The results for co-rotational Maxwell fluid is also obtained by taking material constant ${\mu}_1$ = 0. The effect of the zero shear viscosity ${\eta}_0$, the material constant ${\mu}_1$, the relaxation time ${\lambda}_1$ and gravitational force on the velocity profile for drainage problem are discussed and plotted.

• Korean Journal of Agricultural Science
• /
• v.13 no.2
• /
• pp.255-264
• /
• 1986

The objectives of this study were to examine the viscoelastic behaviour of stem samples of rice in force-relaxation and rheological model to represent its relaxation behaviour, and to study the effects of rate of deformation and initial deformation on the relaxation time. The results were as follows; 1. In the process of loading and unloading, there is any plastic deformation so called elasto-plastic hysterisis. 2. Loading and unloading of stem of rice for several cycles has also shown the reduction of plastic or residual deformation and work hardening. 3. The relaxation behaviour of stem of rice in compression may be described by a generalized Maxwell model consisting of three Maxwell units in parallel. The rheological equation of such a model is given as $$F(t)=C_1e^{{-t/{\tau}}_1}+C_2e^{{-t/{\tau}}_2}+C_3e^{{-t/{\tau}}_3}$$ 4. Force relaxation always increased with increasing rates of deformation and initial deformation.

• 한국가시화정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.128-133
• /
• 2007

An electrostatic inkjet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head has been proposed using the electrostatic force. A numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Also, experiments have been carried out to investigate the droplet movement using a downward capillary with outside diameter of $500{\mu}m$. Gravity, surface tension, and electrostatic force have been analyzed with high voltages for a drop-on-demand ejection. It has been observed that the droplet size decreases and the frequency of the droplet formation and the velocity of the droplet ejection increase with increasing the intensity of the electrostatic field using high-speed camera.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1605-1609
• /
• 2007

In the case of Linear induction motor(LIM), numerical analysis method like Finite Element Method(FEM) has been mainly used to analyze the travelling magnetic field problem which includes the velocity-induced electromotive force. If the problem including the velocity-induced electromotive force is analyzed by FEM using Galerkin method, the solution can be oscillated according to Peclet Number, which is determined by conductivity, permeability, moving velocity and size of mesh. Consequently, the accuracy of the solution can be low and the Loops of flux can be occurred at the secondary back-iron. These loops of flux occurred at the secondary back-iron does not exist physically, but it can be occurred in the analysis. In this case, the loops of flux can be generally removed by using Up-Wind method which is impossible to apply a conventional S/W tool(Maxwell 2D). Therefore, in this paper, authors examined the Loops of flux occurred at the secondary back-iron of LIM according to variations of Peclet Number, and analyzed whether these loops of flux affect on the thrust force characteristics of LIM or not.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.3 no.3
• /
• pp.317-324
• /
• 2014

The forces involved in the firing of the electromagnetic rail gun may be analyzed from Amperian, Maxwellian and Einsteinian approaches. This paper discusses these different paradigms with regard to rail gun performance modeling relating to the generation and balance of the forces caused by the currents and their induced magnetic fields. Recent experimental work on model rail guns, where the armature is held static, shows very little recoil upon the rails, thereby indicating a possible violation of Newton's Third Law of Motion. Dynamic testing to show this violation, as suggested by the authors in an earlier paper, has inherent technical difficulties. A purpose-built finite element C/C++ simulator that models that suspended rail gun firing action shows a net force acting upon the entire rail gun system. A new effect in physics, universal in scope, is thus indicated: a current circulating in an asymmetric and rigid circuit causes a net force to act upon the circuit for the duration of the current. This conclusion following from computer simulation based upon Maxwellian electrodynamics as opposed to the more modern relativistic quantum electrodynamics needs to be supported by unambiguous experimental validation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.227-232
• /
• 2003

Usually, the thrust of a Linear Pulse Motor(LPM) is calculated by magnetic equivalent circuit modelling method. Analytical thrust deviation exists to calculating magnetic flux density by using Permeance Modelling Method, Finite Element Method, and Velocity Electric Motive Force Method. For calculating accuracy thrust by using these every method, the thrust is calculated and compared by Lorentz Force Method, Magnetic Coenergy Method, and Maxwell correspondence force Method. And that becomes important factor at the comparison of each capacity and parameter of motor. So this study wants to compare and analyze measurement data and calculating data of the static thrust of LPM. and then we can get more accuracy method, calculating the static thrust of LPM.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.2
• /
• pp.184-192
• /
• 2012

The torque and unbalanced magnetic forces in permanent magnet machines are resultants of the tangential, axial and normal magnetic forces, respectively. Those are in general influenced by pole-teeth-winding configuration. A study of the torque and unbalanced magnetic forces of a small flux concentrating permanent magnet transverse flux machine (FCPM-TFM) in segmented compact structure is presented in this paper. By using FLUX3D software from Cedrat, Maxwell stress tensor has been solved. Finite element (FE-) magneto static study followed by transient analysis has been conducted to investigate the influence of unsymmetrical winding pattern, in respect to the rotor, on the performance of the FCPM-TFM. Calculating the magnetic field components in the air gap has required an introduction of a 2D grid in the middle of the air gap, whereby good estimations of the forces are obtained. In this machine, the axial magnetic forces reveal relatively higher amplitudes compared to the normal forces. Practical results of a prototype motor are demonstrated through the analysis.

• Structural Engineering and Mechanics
• /
• v.11 no.1
• /
• pp.71-87
• /
• 2001

A frequency domain response analysis is presented for building frames passively controlled by viscoelastic dampers, under harmonic ground excitation. Three different models are used to represent the linear dynamic force-deformation characteristics of viscoelastic dampers namely, Kelvin model, Linear hysteretic model and Maxwell model. The frequency domain solution is obtained by (i) an iterative pseudo-force method, which uses undamped mode shapes and frequencies of the system, (ii) an approximate modal strain energy method, which uses an equivalent modal damping of the system in each mode of vibration, and (iii) an exact method which uses complex frequency response function of the system. The responses obtained by three different methods are compared for different combinations of viscoelastic dampers giving rise to both classically and non-classically damped cases. In addition, the effect of the modelling of viscoelastic dampers on the response is investigated for a certain frequency range of interest. The results of the study are useful in appropriate modelling of viscoelastic dampers and in understanding the implication of using modal analysis procedure for building frames which are passively controlled by viscoelastic dampers against base excitation.

• Journal of the Korean Chemical Society
• /
• v.21 no.5
• /
• pp.330-338
• /
• 1977

In order to elucidate the plastic deformation of solids, the following assumptions were made: (1) the plastic deformation of solids is classified into two main types, the one which is caused by dislocation movement and the other caused by grain boundary movement, each movement being restricted on a different shear surface, (2) the dislocation movement is expressed by a mechanical model of a parallel connection of various kinds of Maxwell dislocation flow units whereas the grain boundary movement is also expressed by a parallel connection of various kinds of Maxwell grain boundary flow units; the parallel connection in each type of movements indicates that all the flow units on each shear surface flow with the same shear rate, (3) the latter model for grain boundary movement is connected in series to the former for dislocation movement, this means physically that the applied stress distributes homogeneously in the flow system while the total strain rate distributes heterogeneously on the two types of shear planes (dislocation or grain boundary shear plane), (4) the movement of dislocation flow units and grain boundary units becomes possible when the atoms or molecules near the obstacles, which hinder the movement of flow units, diffuse away from the obstacles.Using the above assumptions in conjunction with the theory of rate processes, generalized equations of shear stress and shear rate for plastic deformation were derived. In this paper, four cases important in practice were considered.ted N${\cdot}{\cdot}{\cdot}$O hydrogen bond and the second of two normal N${\cdot}{\cdot}{\cdot}$O hydrogen bonds, both of which exist between the amino group and the perchlorate, groups. A p-phenylenediamine group is approximately planar within an experimental error and bonded to twelve perchlorates: ten perchlorates forming hydrogen bonds and two being contacted with the van der Waals forces. A perchlorate group is surrounded by six p-phenylenediamines and four perchlorates; among the six p-phenylenediamines, five of them are hydrogen-bonded, and the rest contacted with the van der Waals force.