• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.232-233
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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 travelingelastic wave induced at the surface of circumference of the elastic disk, a steel bar in contact with the surface of circumference of elastic disk bonded onto the piezoelectric ceramic disks is driven inboth 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 %.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.218-222
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• 2011

This paper proposes a single-joint optical torque sensor with one body structure. Conventional optical torque sensors consist of three parts, two plates and an elastic structure. They have slightly slipping problem between plates and elastic structure due to the manufacturing tolerance. Since the order of measurement range of optical sensor is about ten micrometers, the slipping problem causes large measurement error, especially in the case of vibrational or high speed plant. This problem does not occur in the proposed design due to the one body structure. The proposed sensor has advantage of low cost, light weight, and small size. And it is easy to design and manufacture. Simulation works that analysis of stress and strain are performed accurately. To demonstrate the performance of proposed sensor, experiments were implemented to compare with a commercial force/torque sensor (ATI Mini45).

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.172-177
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• 2003

This paper investigates the effect of reinforced plate on the deflection of the rectangular plate, when the rectangular plate is reinforced with rectangular rigid body at the centroid of the plate. For two boundary conditions such as simple supported and clamped boundary This study derives deflection formula of reinforced plates with three kinds of the aspect ratio of a rectangular plate with respect to the elastic modulus ratio and the length ratio of rigid body using the least square method. The results are as follows: 1. As the elastic modulus ratio r$_{e}$$\geq$ 1000, the maximum deflection with respect to the length ratio r$_{1}$ converges into constant value. 2. Deflection formula with respect to the length ratio r$_{1}$ is derived as the third order polynomial.l.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.585-588
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• 2002

The USM uses friction between a mobile part (rotor) and a vibration part(stator), which is different from the principle of the conventional motor based on the interaction of electric and magnetic fields. In this thesis, a flat-type $L_1-B_8$ mode USM was designed and fabricated the characteristics of an ultrasonic vibration. The results of fabricated USM are as follows: (1) In case of ultrasonic motor with elastic-body of stainless, when applied voltage, frequency, pressing force of rotor were 50 [V], 27.9 [kHz], 1.5 [N], 5.0[mN m] respectively, the speed of revolution could be presented up to 0 [cm/s]. (2) In case of ultrasonic motor with elastic-body of brass, when applied voltage, frequency, pressing force of rotor were 50 [V], 21.4 [kHz], 1.5 [N], 1.4[mN m]respectively, the speed of rotor revolution was presented up to 0 [cm/s]. (3) The USM of elastic-body of stainless showing 1.17[%], somewhat low, in the maximum efficiency according to torque was superior to the USM of elastic-body of brass showing 0.34 [%]. The Flat-type $L_1-B_8$ mode USM had characteristics of typical drooping torque-speed, large torque and high speed, and operating in both directions by phase reversal.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.1-6
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• 2015

Generating output characteristics of a ${\pi}$-type piezoelectric harvester depending on size of the ceramic and the elastic body were studied. The ${\pi}$-type piezoelectric harvester consists of a rectangular piezoelectric ceramic and a ${\pi}$ shaped elastic body. If the tensions is applied at both ends of an elastic body legs, the piezoelectric effect occurs at the ceramics through the form change of the elastic body. The structure of this ${\pi}$-type harvester can be used in a various area than an existing type generator, because it prevent from direct pressure to the ceramic. Generating characteristics of the harvester were analyzed by using finite element method program. The piezoelectric harvester was fabricated on the basis of analyzed results and attached on a frequency controllable vibrator to measure the output characteristics. And generating characteristics were defined by comparing analysis results and experimental results. The highest output voltage was obtained when the ceramic length, thickness were 20 mm, 0.5 mm in the analysis result. And experiment was performed by analysis results at low frequency region, output voltage was generated about 6 V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.8
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• pp.635-639
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• 2013

Generating output characteristics of a EYE-type piezoelectric generator depending on ceramic size and materials of the elastic body were studied. EYE-type piezoelectric-generating device consist of the ceramic was attached between the both elastic body. piezoelectric-generating is that if the tension occurred at both ends of an elastic body, the piezoelectric effect occurs at ceramics through the form change of the elastic body. The structure of this EYE-type generator use various area. than a existing type generator, because the ceramic position of the directly force at does not apply. Resonance and output characteristics of the generator were analyzed by using FEM program. Generators were fabricated on the basis of analyzed results and attached on a frequency controllable vibrator to measure output characteristics. Also, the experimental results were compared with the simulated results. As a result, output characteristics of the generator increased depending on the increase in ceramic thickness. In case of increase in ceramic width, resonance frequency of the generator also decreased.

• Journal of Korean Academy of Nursing
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• v.42 no.7
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• pp.947-956
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• 2012

Purpose: To investigate the effect of progressive resistance training (PRT) on body composition, physical fitness, quality of life, lipid and nutritional profile of patients on hemodialysis (HD). Methods: A non equivalent comparison group pretest and posttest design study was used with 40 participants who were randomly assigned to the exercise group (20 participants) and the comparison group (20 participants). The exercise group received PRT for 30 minutes per session, 3 sessions a week, for 12 weeks, while the comparison group received usual care. The PRT consisted of upper and lower body exercises using elastic bands and sandbags. Outcome measures evaluated were: body composition, physical fitness, quality of life, and lipid profile. Results: Skeletal muscle mass, grip, leg muscle strength, and quality of life all improved significantly in the exercise group. Body fat rate, total cholesterol and triglyceride rate decreased significantly in the exercise group. Conclusion: These results suggest that PRT improves body composition, physical fitness, quality of life, and lipid profile of patients on HD. PRT using elastic bands and sandbags can be utilized as part of a regular care plan for these patients.

• Membrane and Water Treatment
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• v.11 no.4
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• pp.295-302
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• 2020

In this paper, theoretical approach with applications of the periodic wave solutions in an elastic material is applied by study the effect of initial stress, and rotation, on the radial displacement and the corresponding stresses in non-homogeneous orthotropic material. An Analytical solution for the elastodynamic equation has obtained concerning the component of displacement. The variations of stresses and displacements have shown graphically. Comparisons with previously published results in the absence of initial stress, rotation and non-homogeneity have made. Finally, numerical results have given and illustrated graphically for each case considered.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.191-192
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• 2005

In this study, the ultrasonic motor which has hollowed cross type stator was designed, and the elastic body of ultrasonic motor was optimized by using a finite element analysis program(ANSYS 9.0). When the length of leg(L) of the elastic body was increased and the width of piezoceramics was decreased, the resonant frequency was increased and the displacement of contact point between the rotor and the stator was increased. However, when the length of the leg was over the 1/3 point of the width of ceramics, the displacement of the contact point was decreased, because the elastic buckle was generated in the leg.

• Structural Engineering and Mechanics
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• v.4 no.5
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• pp.469-484
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• 1996

Green's functions are obtained in exact closed-forms for the elastic fields in bi-material elastic solids with slipping interface and differing transversely isotropic properties induced by concentrated point and ring force vectors. For the concentrated point force vector, the Green functions are expressed in terms of elementary harmonic functions. For the concentrated ring force vector, the Green functions are expressed in terms of the complete elliptic integral. Numerical results are presented to illustrate the effect of anisotropic bi-material properties on the transmission of normal contact stress and the discontinuity of lateral displacements at the slipping interface. The closed-form Green's functions are systematically presented in matrix forms which can be easily implemented in numerical schemes such as boundary element methods to solve elastic problems in computational mechanics.