• Journal of Magnetics
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• v.18 no.3
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• pp.250-254
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• 2013

In this research, the linear electrical generator in wave energy farm utilizing resonance power buoy system is studied. The mechanical resonance characteristics of the buoy and the wave are analyzed to maximize the kinetic energy in a relatively small wave energy area where WRPS is operated. In this research, we chose an analog model of the linear electrical generator of which size is one-hundredth of an actual size of it in WPRS (Wave energy farm utilizing Resonance Power buoy System) prior to verifying the characteristics of actual model of linear electrical generator in WRPS. In addition, the finite element analysis is conducted using commercial electromagnetic analysis software named MAXWELL to examine the electric characteristic of linear generator. Finally, for the verification of dynamic and electric characteristics of linear generator, the prototype was manufactured and the experiments to measure the displacement and the output electric power were performed.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.68-73
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• 2020

Skin-stringer structures are widely used in aircrafts due to their advantage of minimizing structural weight while maintaining load carrying capacity. However, buckling load can cause serious damage to these structures. Therefore, the buckling characteristics of skin-stringer structures should be carefully considered during the design phase to ensure structural soundness. In this study, finite element method was applied to predict the buckling characteristics of stiffened panels. In terms of the failure mode, finite element analysis showed a symmetrical buckling mode, whereas an asymmetrical mode was determined by experimentation. The numerical results were obtained and compared to the experimental data, showing a difference of 9.3% with regard to the buckling loads.

• Journal of Mechanical Science and Technology
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• v.18 no.6
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• pp.955-960
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• 2004

Some characteristics of the eigenvalue sensitivities have been found for beams in the paper. For cantilever beams and simply supported beams, the sensitivities of the eigenvalues to the stiffness correction factor of one element are equal and opposite to the sensitivities to the mass correction factor of the symmetrically positioned element. For beams with other boundary conditions, however, the relationship does not hold. The relationship has been proven analytically for simply supported beams.

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.40-47
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• 2003

In this paper, we constructed the analytic model of control valve as a function of electric and geometric parameters, and analyzed the influence of the design parameters on the dynamic characteristics. For improving the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design aims to minimize the response time and maximize force efficiency. By this procedure, control valve can be designed to have fast response in motion.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.455-465
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• 2007

The bushing element shows nonlinear characteristics in both displacements and frequencies, also with hysteretic responses for repeated vibrational excitations. Since the characteristics of the rubber bushing significantly affects the accuracy of the vehicle dynamic simulation result, it should be accurately modeled in the vehicle suspension model. To develop an accurate bushing model for vehicle dynamics analysis, the bushing characteristics under several excitation inputs must be known. In this paper, a 3-axis tester was used to capture the bushing characteristics. The random inputs, sine inputs, and step inputs were imposed on each axis of the bushing. Also, two-axis inputs, the radial-axial and radial-normal inputs, were simultaneously imposed on the tester. Three-axis inputs including the radial-axial-normal direction were supplied to the tester. Bushing characteristics of each case were precisely analyzed. These results could be available for dynamic modeling of bushing.

• Tribology and Lubricants
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• v.29 no.1
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• pp.39-45
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• 2013

Magnetorheological (MR) fluid belongs to the group of smart materials. In MR fluid, iron particles in base oil form chains in the direction of the applied magnetic field, thus resulting in a variation in the stiffness and damping characteristics of the fluid. Research is being carried out on controlling the stiffness and damping characteristics as well as the tribological characteristics of the MR fluid. In this study, the friction characteristics of MR fluid have been evaluated using three types of materials and magnetic fields of different strengths. The coefficients of friction of the three types of MR fluid are measured, and the relationship between the coefficient of friction and the strength of the applied magnetic field is obtained.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.225-232
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• 1999

The effect of manufacturing parameters such as molding and curing conditions on friction characteristics of friction materials was studied using a pad-on-disk type friction tester. Friction materials containing 15 ingredients were investigated for an optimal manufacturing condition for the best friction characteristics employing Taguchi robust experimental design. The main effects were different for mechanical properties and friction characteristics and were strongly influenced by manufacturing conditions. An optimum manufacturing condition was obtained to achieve the best friction characteristics concerning mechanical properties(hardness, porosity, wear resistance), friction stability, and change of rotor temperature.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1576-1582
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• 2002

Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins which takes place through the motor airgap. When relative misalignment of a rotor in the airgap is introduced during assembly, the dynamic characteristics of the motor system are affected. The rotor-motor system used in a washing machine is modeled using FETM and magnetic forces in a BLDC motor with radial rotor eccentricity are determined analytically The transient whirl responses of a rotor system supported on two roller bearings with relative misalignment in the motor airgap are investigated by considering mechanical and magnetic coupling effects. Results show that rotor misalignment in the airgap considerably affects the vibration of the rotor-motor system.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.3
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• pp.210-217
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• 2002

This study was carried out to investigate the possibility of improving the texture and the flavor of Dasik made of the Omija extract, various sugars and rice powder. Sensory quality and mechanical characteristics of Dasik were compared. The moisture content of the Croup of tile Dasik added with Omija extract was higher than that with non-Omija extract The Omija Dasik containing molasses showed the highest value (23.5%) in moisture content. In sensory quality, Omija Dasik containing honey and symp showed the highest score in overall acceptability (6.2 and 6.0, respectively). The Rice Dasik containing syrup showed the highest values in lightness (L) and yellowness (b) in color. The Omija Dasik containing syrup showed the highest values in redness (a) in color. The Dasik added with honey and syrup were lower in hardness, but higher in cohesiveness, springiness, gumminess and brittleness of textural characteristics. When sensory quality and mechanical characteristics of the Dasik were compared with, the gumminess and brittleness in mechanical characteristics were positively correlated with the appearance and the taste acceptability in sensory quality (p<.01, p<.05). The springiness was negatively correlated with the tooth packing in sensory quality (p<.001). The Omija Dasik was more desirable in flavor, taste and overall acceptability, especially those added with honey and syrup. From the above results, the honey might be replaced by the less expensive syrup, when making the Omija Dasik.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.110-117
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• 2007

This study investigated changes of mechanical characteristics of the trabecular and cortical bone in the lumbar vertebrae of the ovariectomised (OVX) rat. In previous researches, there were many studies for morphology of osteoporotic bones based on Micro-Computed Tomography (Micro-CT). However, there were few studies for detecting and tracking changes of mechanical characteristics of the trabecular and cortical bone in the lumbar vertebrae of the OVX rat. For this study, the 4th lumbar of the OVX rat (female Sprague-Dawley) was utilized as a specimen. An OVX rat was scanned at week 0 (just before surgery), at week 4, and week 8 after surgery. Micro-finite element (${\mu}-FE$) analysis was used to investigate mechanical characteristics of the trabecular and cortical bone in the lumbar vertebrae for an OVX rat. When the OVX rat (at week 8) was compared with the OVX rat (at week 0), the structural modulus of cortical and trabecualr bone was decreased by 52% and 99%, respectively. This study showed the change of mechanical characteristics of cortical bone as well as trabecular bone of an OVX rat. Detecting and tracking changes of mechanical characteristics could greatly contribute to an experiment test for the trabecular and cortical bone in the lumbar vertebrae of an OVX rat by using In-vivo Micro-CT.