• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.15-21
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• 2001

This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop an analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1073-1079
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• 1998

The potential energy surface (PES) of the non-identical SN2 reactions, F- + CH3Cl → FCH3 + Cl and (H2O)F + CH3Cl → FCH3 + Cl-(H2O), were investigated with ab initio MO calculations. The ab initio minimum energy reaction path (MERP) of the F- + CH3Cl → FCH3 + Cl- was obtained and it was expressed with an intermediate variable t. The ab initio PES was obtained near around t. Analytical potential energy function (PEF) was determined as a function of the t in order to reproduce the ab initio PES. Based on Morse-type potential energy function, a Varying Repulsive Cores Model (VRCM) was proposed for the description of the bond forming and the bond breaking which occur simultaneously during the SN2 reaction. The MERP calculated with the PEF is well agreed with the ab initio MERP and PEF could reproduce the ab initio PES well. The potential parameters for the interactions between the gas phase molecules in the reactions and water were also obtained. ST2 type model was used for the water.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.947-952
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• 2021

In this paper, the simplified kinematic error model for Delta parallel robot is presented, which can enable the analytical forward kinematics essentially for kinematic calibration calculations instead of the numerical one. The simplified kinematic error model is proposed and the forward kinematics including the error parameters is analytically derived. The kinematic calibration algorithm of the Delta parallel robot with 90 degree arrangement using laser tracker and the experiment result are presented.

• Coupled systems mechanics
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• 제10권2호
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• pp.185-198
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• 2021

An analytical model is consider to scrutinize axisymmetric wave propagation in multiferroic hollow cylinder with rotating and initial stressed forces, where a piezomagnetic (PM) material layer is bonded to a piezoelectric (PE) cylinder together by Linear elastic materials with voids. Both distinct material combos are taken into account. Three displacement potential functions are introduced to uncouple the equations of motion, electric and magnetic induction. The numerical calculations are carried out for the non-dimensional frequency by fixing wave number and thickness. The arrived outputs are plotted as the dispersion curves for different layers. The results obtained in this paper can offer significance to the application of PE/PM composite hollow cylinder via LEMV and CFRP layers for the acoustic wave and microwave technologies.

• Computers and Concrete
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• 제27권3호
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• pp.269-282
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• 2021

A dynamic analytical solution for a simply supported, rectangular functionally graded plate with a porous middle layer under time-dependent load based on a refined third-order shear deformation theory with a cubic variation of in-plane displacements according to the thickness and linear/quadratic transverse displacement is presented. The solution achieved in the trigonometric series form and rests on the Green's function method. Two porosity types and their influence on material properties, and mechanical behavior are considered. The network of pores is assumed to be empty or filled with low-pressure air, and the material properties are calculated using the power-law distribution idealization. Numerical calculations have been carried out to demonstrate the accuracy of the kinematic model for the dynamic problem, the effect of porosity, thickness of porous layers, power-law index, and type of loading on the dynamic response of an imperfect functionally graded material plate.

• Geomechanics and Engineering
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• 제24권4호
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• pp.399-406
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• 2021

It is a key issue in the tunnel design to evaluate the stability of the excavation face. Two efficient analytical models in the context of the limit equilibrium method (LEM) and the limit analysis method (LAM) are used to carry out the deterministic calculations of the safety factor. The safety factor obtained by these two models agrees well with that provided by the numerical modelling by FLAC 3D, but consuming less time. A simple probabilistic approach based on the Mote-Carlo Simulation technique which can quickly calculate the probability distribution of the safety factor was used to perform the probabilistic analysis on the tunnel face stability. Both the cumulative probabilistic distribution and the probability density function in terms of the safety factor were obtained. The obtained results show the effectiveness of this probabilistic approach in the tunnel design.

• Earthquakes and Structures
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• 제24권3호
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• pp.193-204
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• 2023

The concept of meta-material-based isolation systems (MMIS) for structural columns has been revisited in the present study in order to enhance the stability of rubber pads by using steel shim reinforced rubber (SSRR) layers. Analytical calculations have shown a significant improvement in the stability of MMIS with SSRR pads. Finite element analysis has also been conducted to further show the reduced response of a bridge with the modified MMIS under excitations having frequencies within the corresponding attenuation zone (AZ) as compared to the response of a conventional bridge without MMIS. FE analysis further shows the stress generated on the bridge with MMIS systems are within safe limits. Finally, a generalized procedure has been developed to design bridge columns with the proposed modified MMIS.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2864-2872
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• 2023

The criticality problem in this study is studied with the recently investigated the Anlı-Güngör scattering function. The scattering function depends on the Legendre polynomials as the Mika scattering function, but it includes only one scattering parameter, t, and its orders. Both Mika and Anlı-Güngör scattering are the same for only linear anisotropic scattering. The difference appears for the quadratic scattering and further. The analytical calculations are performed with the H_N method, and the numerical results are calculated with Wolfram Mathematica. Interpolation technique in Mathematica is also used to approximate the isotropic scattering results when t parameter goes to zero. Thus, the calculated results could be compared with the literature data for isotropic scattering.

• Advances in nano research
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• 제13권4호
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• pp.341-350
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• 2022

The continuous elements method, also known as the dynamic stiffness method, is effective for solving structural dynamics problems, especially over a large frequency range. Before applying this method to fluid-structure interactions, it is advisable to check its validity for pure acoustics, without considering the different coupling parameters. This paper describes a procedure for taking wave propagation into account in the formulation of a Dynamic Stiffness Matrix. The procedure is presented in the context of the harmonic response of acoustic pressure. This development was validated by comparing the harmonic response calculations performed using the continuous element model with the analytical solution. In addition, this paper illustrates the application of this method to a simple compressible flow problem, since it has been applied solely to structural problems to date.

• Advances in materials Research
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• 제13권4호
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• pp.253-267
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• 2024

The current study attempts to discuss the effects of viscosity and locality on a fiber-reinforced thermoelastic solid. The problem is solved analytically in the context of the three-phase-lag model as well as the Green-Naghdi theory without energy dissipation (G-N II). The method of normal mode analysis is used to obtain analytical expressions for the displacement, stress, and temperature distributions. Compute the physical fields with suitable boundary conditions and perform numerical calculations using MATLAB programming. Comparisons are carried out with the results in the absence and presence of locality as well as viscosity. The locality and viscosity have great effects on all considered physical fields since the amplitudes of these quantities are vary. This procedure remains valid when a nonlocal elastic solid is replaced with an elastic one.