• 한국정밀공학회지
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• 제18권7호
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• pp.134-142
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• 2001

The integrals $J_k$(k=1,2) in the rectilinear anisotropis body in 2-D were determined using Lekhnitskii formalism. The relationship between $J_k$ and stress intensity factors are implified by the important equation between elastic compliance. The numerical evaluation of stress intensity factor for the single edge crack in mixed mode is determined by superposing known exact solutions.

• 대한물리의학회지
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• 제5권1호
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• pp.113-123
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• 2010

Purpose : The purpose of this study was to investigate how upper-extremity-movement of PNF(proprioceptive neuromuscular facilitation) with elastic band has effected on arrangement of body and weight-bearing. Methods : The object has worked with 20 patient

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권10호
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• pp.484-490
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• 2003

This paper describes with the stator analysis and design of a ring type ultrasonic motor. The design for piezoelectric ceramic and elastic body of stator were calculated by using the finite element method (FEM) that consider the resonance frequency, vibration mode and coupling efficiency. Namely, such results were acquired the calculation result of the piezoelectric ceramic thickness 0.5[mm], elastic body thickness 2.0[mm], resonance frequency 51.8[kHz], vibration mode 7 order and coupling efficient 12.5[%], the outer and inner diameter of vibrator 50[mm], 38[m]. On the basis of such result, the ring type ultrasonic motor was manufactured. Also for driving characteristics of ring type ultrasonic motor, 2-phase inverter was constructed. Then the propriety of this paper was established from comparision of the simulation and an experiment results of the ring type ultrasonic motor.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권10호
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• pp.583-588
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• 2000

This paper presents the design and fabrication of micro electromagnetic vibration silicon elastic body characterized with small size, high efficiency and selective frequency bandwidth for Bio-MENS applications, such as implantable middle ear hearing aid. The presented electromagnetic vibration transducer that composed of wounded coil, permanent magnet and 4-beam cross type elastic body is fabricated by using of micromachining technology. The fabricated transducer has experimental characteristics, that is 5 nm/mA of an energy trasfer rate at the frequency range of 100∼2800 Hz. It has a size of $2{\times}2{\times}2.5\;mm^3$.

• Structural Engineering and Mechanics
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• 제83권1호
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• pp.67-77
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• 2022

In this study, frictionless continuous and discontinuous contact problems of a magneto-electro-elastic layer in the presence of the body force were discussed. The layer was indented by a rigid cylindrical insulating punch and supported by a rigid substrate without bond. Applying the Fourier integral transform technique, the general expressions of the problem were derived in the presence of body force. Thanks to the boundary conditions, the singular integral equations were obtained for both the continuous and the discontinuous contact cases. Gauss-Chebyshev integration formulas were used to transform the singular integral equations into a set of nonlinear equations. Contact width under the punch, initial separation distance, critical load, separation regions and contact stress under the punch and between the layer, and substrate were given as a result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.168-171
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• 2005

In this paper, disk-type ultrasonic motor using a combination of radial and bending vibration modes is newly designed and fabricated. The characteristics of the test motor are also measured. By means of traveling elastic wave induced at the surface of circumference of the elastic disk, a steel bar in contact with the surface of circumferenceof elastic disk bonded onto the piezoelectric ceramic disks is driven in both directions by changing the sine and cosine voltage inputs. The stator of the motor is composed of two sheets of piezoelectric ceramic disk to bond onto both surfaces of a elastic disk, respectively. As the results, the diameter of elastic body is increased, the resonant frequency is decreased. The resonant frequency of the stator is about 92 kHz, which is composed with piezoelectric ceramic disks of 28 mm in diameter and 2 mm in thickness, and an elastic body of 32 mm in diameter and 2 mm in thickness. A driving voltage of 20 Vpp produces 200 rpm with a torque of 1Nm and an efficiency of about 10 %.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1365-1381
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• 2023

In this paper, a procedure for evaluating the structural integrity of the PCSG (Printed Circuit Steam Generator) unit block is presented with a simplified FE (finite element) analysis technique by applying the homogenization method. The homogenization method converts an inhomogeneous elastic body into a homogeneous elastic body with same mechanical behaviour. This method is effective when the inhomogeneous elastic body has repetitive microstructures, and thus the method was applied to the sheet assembly among the PCSG unit block components. From the method, the homogenized equivalent elastic constants of the sheet assembly were derived. The validity of the determined material properties was verified by comparing the mechanical behaviour with the reference model. Thermo-mechanical analysis was then performed to evaluate the structural integrity of the PCSG unit block, and it was found that the contact region between the steam header and the sheet assembly is a critical point where large bending stress occurs due to the temperature difference.

• Journal of Astronomy and Space Sciences
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• 제15권1호
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• pp.209-220
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• 1998

The stability problem of steady motion of a rigid body with multi-elastic appendages and multi-liquid-filled cavities, in the presence of no external forces or torque, is considered in this paper. The flexible appendages are modeled as the clamped -free-free-free rectangular plates, or/and as the discrete mass- spring sub-system. The motion of liquid in every single ellipsoidal cavity is modeled as the uniform vortex motion with a finite number of degrees of freedom. Assuming that stationary holonomic constraints imposed on the body allow its rotation about a spatially fixed axis, the equation of motion for such a systematic configuration can be very complex. It consists of a set of ordinary differential equations for the motion of the rigid body, the uniform rotation of the contained liquids, the motion of discrete elastic parts, and a set of partial differential equations for the elastic appendages supplemented by appropriate initial and boundary conditions. In addition, for such a hybrid system, under suitable assumptions, their equations of motion have four types of first integrals, i.e., energy and area, Helmholtz' constancy of liquid - vortexes, and the constant of the Poisson equation of motion. Chetaev's effective method for constructing Liapunov functions in the form of a set of first integrals of the equations of the perturbed motion is employed to investigate the sufficient stability conditions of steady motions of the complete system in the sense of Liapunov, i.e., with respect to the variables determining the motion of the solid body and to some quantities which define integrally the motion of flexible appendages. These sufficient conditions take into account the vortexes of the contained liquids, the vibration of the flexible components, and coupling among the liquid-elasticity solid.

• Advances in concrete construction
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• 제13권3호
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• pp.255-264
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• 2022

Vibration is expected to occur in microtubules as tubular heterodimers. They oscillate like electric dipoles. Several research studies have estimated a frequency of vibration using the orthotropic model, a beam or rod like models and shell models, considering the surface forces. The effects of body forces on the dynamics of the microtubules were not yet taken into account. This study seeks to capture the body force effects on the vibration modes generated and on the corresponding frequency for microtubules. An orthotropic elastic shell model for the structural details of microtubules is used for the analysis. The tests are conducted out for microtubules, exposed to electro-magnetic and gravitational forces, the transverse vibration, radial mode vibration, and axial mode of vibration have accomplished. We therefore, evaluate and compare microtubules' frequencies with prior results of vibration frequency without the effects of body force.

• 대한기계학회논문집A
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• 제31권10호
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• pp.1009-1016
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• 2007

Finite element alternating method has been suggested and used effectively to obtain the fracture parameters in assessing the integrity of cracked structures. The method obtains the solution from alternating independently between the FEM solution for an uncracked body and the crack solution in an infinite body. In the paper, the finite element alternating method is extended in order to obtain the elastic-plastic stress fields of a three dimensional inner crack. The three dimensional crack solutions for an infinite body were obtained using symmetric Galerkin boundary element method. As an example of a three dimensional inner crack, a penny-shaped crack in a finite body was analyzed and the obtained elastc-plastic stress fields were compared with the solution obtained from the finite element analysis with fine mesh. It is noted that in the region ahead of the crack front the stress values from FEAM are close to the values from FEM. But large discrepancy between two values is observed near the crack surfaces.