• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.769-777
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• 2017

The research of air gap flux density has a significant effect on predicting and optimizing the structure parameters of electrical machines. In the paper, the air gap coefficient, leakage flux factor and saturation coefficient are first analytically expressed in terms of motor properties and structure parameters. Subsequently, the analytical model of average air gap flux density for surface-mounted permanent magnet synchronous machines is proposed with considering slotting effect and saturation. In order to verify the accuracy of the proposed analytical model, the experiment and finite element analysis (FEA) are used. It shows that the analytical results keep consistency well with the experimental result and FEA results, and the errors between FEA results and analytical results are less than 5% for SPM with high power. Finally, the analytical model is applied to optimizing the motor structure parameters. The optimal results indicate that the analytical calculation model provides a great potential to the machine design and optimization.

• 한국정밀공학회지
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• 제18권2호
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• pp.102-110
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• 2001

In this paper, methods to analyze wire sweep and paddle shift during the semiconductor ship-encapsulation process have been studied. The analysis of wire sweep includes flow-field analysis in a complicated geometry, drag-force calculation for given flow of fluid, and wire-deformation calculation for given loads. The paddle-shift analysis is used to analyze the deformation of the paddle due to the pressure difference in two cavities. the analysis is done using either analytical solutions or numerical simulation. The analytical solution is used for rough but fast calculation of wire sweep. The numerical solution is used for more accurate calculation of wire-sweep. The numerical results of wire sweep show good agreements with the experimental ones.

• 분석과학
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• 제8권3호
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• pp.383-389
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• 1995

A new approach for the measurement of the surface coverages of monomolecular films fabricated by spontaneous adsorption of thiol compounds on gold is described. It is based on the mass change measurement with EQCM for the reductive electrochemical desorption of thiol in aqueous KOH solution. The results were compared with that of charge calculation during electrochemical desorption. The surface coverage value for eicosanethiol agrees with that obtained by charge calculation of electrochemical reduction as well as that expected from a geometrical model of the compact monolayer.

• Bulletin of the Korean Chemical Society
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• 제5권4호
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• pp.145-149
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• 1984

The entropy and heat capacity are calculated for the Morse oscillator model in order to test the quality of the partition function recently deduced by two of us. It is found that these analytical expressions are more reliable than the usually accepted one and give better results in the calculation of thermodynamic properties.

• Structural Engineering and Mechanics
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• 제64권1호
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• pp.81-92
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• 2017

Many materials in engineering exhibit different modulus in tension and compression, which are known as bi-modulus materials. Based on the bi-modulus elastic theory, a modified semi-analytical model, by introducing a stress function, is established in this paper to study the mechanical response of a bi-modulus cylinder placed in an axisymmetric temperature field. Meanwhile, a numerical procedure to calculate the temperature stresses in bi-modulus structures is developed. It is proved that the bi-modulus solution can be degenerated to the classical same modulus solution, and is in great accordance with the solutions calculated by the semi-analytical model proposed by Kamiya (1977) and the numerical solutions calculated both by the procedure complied in this paper and by the finite element software ABAQUS, which demonstrates that the semi-analytical model and the numerical procedure are accurate and reliable. The result shows that the modified semi-analytical model simplifies the calculation process and improves the speed of computation. And the numerical procedure simplifies the modeling process and can be extended to study the stress field of bi-modulus structures with complex geometry and boundary conditions. Besides, the necessity to introduce the bi-modulus theory is discussed and some suggestions for the qualitative analysis and the quantitative calculation of such structure are proposed.

• Smart Structures and Systems
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• 제31권5호
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• pp.517-529
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• 2023

Using a device composed of two lateral pressure plates (LPPs) and a steel reinforcement bar to apply horizontal pressure on slope surfaces, a newly developed prestress-reinforced embankment (PRE) is proposed, to which can be adopted in strengthening railway subgrades. In this study, an analytical model, which is available of calculating additional confining stress (σ_H) at any point in a PRE, was established based on the theory of elasticity. In addition, to verify the proposed analytical model, three dimensional (3D) finite element analyses were conducted and the feasibility in application was also identified and discussed. In order to study the performance of the PRE, the propagation of σ_H in a PRE was analyzed and discussed based on the analytical model. For the aim of convenience in application, calculation charts were developed in terms of three dimensionless parameters, and they can be used to accurately and efficiently predict the σ_H in a PRE regardless of the embankment slope ratio and LPP side length ratio. Finally, the potential applications of the proposed analytical model were discussed.

• Steel and Composite Structures
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• 제26권1호
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• pp.79-87
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• 2018

In order to study the natural vibration characteristics of steel-concrete composite truss beam (SCCTB), the influence of multiple factors such as interface slip, shear deformation and moment of inertia are considered. Afterwards, based on the Hamilton principle the vibration control differential equation and natural boundary conditions of SCCTB are deduced. By solving SCCTB differential equations of vibration control, an analytical calculation method is proposed for analyzing the natural vibration characteristics of SCCTB. The natural frequencies of SCCTBs with different degrees of shear connection and effective lengths are calculated by using the analytical method, and the results are compared against those obtained from ANSYS finite element numerical calculation method. The results show that the analytical method considering the influence factors such as interface slip, shear deformation and moment of inertia are in good agreement with those obtained from ANSYS finite element numerical calculation method. This evidences the correctness of the analytical method and show that the method proposed exhibits improvement over the previously developed theories for the natural vibration characteristics of SCCTB. Finally, based on the analytical method, the influence factors of SCCTB natural vibration characteristics are analyzed. The results indicate that the influence of interface slip stiffness on SCCTB's natural frequency is more than 10% and therefore cannot be neglected. Moreover, shear deformation has an effect of more than 35% on SCCTB's natural frequency and the effect cannot be ignored either in this case too.

• Structural Engineering and Mechanics
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• 제90권2호
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• pp.159-175
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• 2024

In order to solve the problem of calculating the reasonable completed bridge state of a self-anchored hybrid cable-stayed suspension bridge (SA-HCSB), this paper proposes an analytical method. This method simplifies the main beam into a continuous beam with multi-point rigid supports and solves the support reaction forces. According to the segmented catenary theory, it simultaneously solves the horizontal forces of the main span main cables and the stay cables and iteratively calculates the equilibrium force system on the main beam in the collaborative system bridge state while completing the shape finding of the main span main cable and stay cables. Then, the horizontal forces of the side span main cables and stay cables are obtained based on the balance of horizontal forces on the bridge towers, and the shape finding of the side spans are completed according to the segmented catenary theory. Next, the difference between the support reaction forces of the continuous beam with multiple rigid supports obtained from the initial and final iterations is used to calculate the load of ballast on the side span main beam. Finally, the axial forces and strains of each segment of the main beam and bridge tower are obtained based on the loads applied by the main cable and stay cables on the main beam and bridge tower, thereby obtaining analytical data for the bridge in the reasonable completed state. In this paper, the rationality and effectiveness of this analytical method are verified through a case study of a SA-HCSB with a main span of 720m in finite element analysis. At the same time, it is also verified that the equilibrium force of the main beam under the reasonably completed bridge state can be obtained through iterative calculation. The analytical algorithm in this paper has clear physical significance, strong applicability, and high accuracy of calculation results, enriching the shape-finding method of this bridge type.

• 분석과학
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• 제13권5호
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• pp.1079-1087
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• 2000

• Journal of Magnetics
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• 제19권1호
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• pp.37-42
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• 2014

The equivalent model of a permanent magnet (PM) plays an important role in electromagnetic system calculation. A type of subsection model for a PM bar is established, to improve the accuracy of the traditional equivalent circuit method. The mathematical expression, and its end verification condition, are presented. Based on the analytical method and finite element method, the leakage permeance calculation of a PM bar in an open magnetic circuit is investigated. As an example, for a given certain type of PM bar, the magnetic flux of each section is validated by experiment, and by simulation. This model offers a foundation for building a high accuracy equivalent magnetic PM model in an electromagnetic system.