• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.658-664
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• 2013

Bending actuators composed of cellulose with an electrically conducting polymer (CP) are fabricated and their performance is characterized in the air. Two different counter ions, perchlorate and tetrafluoroborate are used as dopant ions in the polyaniline CP processing. CP-cellulose-CP trilayer and CP-cellulose bilayer samples are fabricated with different dopant ions, and their actuation performance is evaluated in terms of tip displacement, blocked force and electrical power consumption along with the humidity level and actuation frequency. The trilayer samples substantially enhanced the tip displacement compared to the bilayer ones. The actuation performance of the trilayer actuator is three times better than that of original cellulose electro-active paper (EAPap) actuator. The displacement and blocked force of CP-EAPap actuators are dependent on the humidity and frequency.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.9
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• pp.2181-2190
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• 1993

An electro-hydraulic controlled rig type CVT(Continuously Variable Transmission) system was developed and its performance tests were carried out for the optimal operation. A CVT map was suggested based on the speed ration-axial force-torque relationship which was derived from the metal belt CVT mechanics. Also, a real time control and operation software was developed for the electro-hydraulic CVT system. By using the software and the CVT map, the control system was designed for the CVT speed ratio control with various drive modes. The electro-hydraulic CVT system developed in this study showed that the optimal operation algorithm could be obtained for the best fuel economy or the maximum power mode.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.73-76
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• 2007

Electro-Active paper (EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, which result good correlation with each other.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1179-1183
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• 2007

Electro-Active paper(EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, and which result in good correlation with each other.

• Advances in nano research
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• v.7 no.1
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• pp.63-75
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• 2019

This article represents a quasi-3D theory for the buckling investigation of magneto-electro-elastic functionally graded (MEE-FG) nanoplates. All the effects of shear deformation and thickness stretching are considered within the presented theory. Magneto-electro-elastic material properties are considered to be graded in thickness direction employing power-law distribution. Eringen's nonlocal elasticity theory is exploited to describe the size dependency of such nanoplates. Using Hamilton's principle, the nonlocal governing equations based on quasi-3D plate theory are obtained for the buckling analysis of MEE-FG nanoplates including size effect and they are solved applying analytical solution. It is found that magnetic potential, electric voltage, boundary conditions, nonlocal parameter, power-law index and plate geometrical parameters have significant effects on critical buckling loads of MEE-FG nanoscale plates.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.126-132
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• 2023

Recently, the consideration of eco-friendly technology to reduce greenhouse gas is being emphasized in the aviation field. Various studies for applying electro-mechanical actuators that control mechanical linear and rotational movements using electricity as the primary power source are in progress. In this study, the fatigue analysis of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was carried out. A unit load stress table was constructed for the vulnerable part selected through structural analysis, and the representative stress for each load profile was calculated using the unit load stress table constructed for the vulnerable part. Then, individual profiles of representative stress group were extracted from continuous load profiles by applying the rainflow counting method. The damage of each profile was calculated by applying the S-N diagram. Finally, the total damage in the vulnerable parts was calculated by the linear cumulative damage law, and the fatigue life of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was evaluated.

• Advances in nano research
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• v.5 no.4
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• pp.337-357
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• 2017

Knowledge of thin films mechanical properties is strongly associated to the reliability and the performances of Nano Electro Mechanical Systems (NEMS). In the literature, there are several methods for micro materials characterization. Bulge test is an established nondestructive technique for studying the mechanical properties of thin films. This study improve the performances of NEMS by investigating the mechanical behavior of Nano rectangular thin film (NRTF) made of new material embedded in Nano Electro Mechanical Systems (NEMS) by developing the bulge test technique. The NRTF built from adhesively-bonded layers of basalt fiber reinforced polymer (BFRP) laminate composite materials in Nano size at room temperature and were used for plane-strain bulging. The NRTF is first pre-stressed to ensure that is no initial deflection before applied the loads on NRTF and then clamped between two plates. A differential pressure is applying to a deformation of the laminated composite NRTF. This makes the plane-strain bulge test idea for studying the mechanical behavior of laminated composite NRTF in both the elastic and plastic regimes. An exact solution of governing equations for symmetric cross-ply BFRP laminated composite NRTF was established with taking in-to account the effect of the residual strength from pre-stressed loading. The stress-strain relationship of the BFRP laminated composite NRTF was determined by hydraulic bulging test. The NRTF thickness gradation in different points of hemisphere formed in bulge test was analysed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.199-203
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• 1989

본 연구에서 제작된 시험기는 연구자 개인의 경제적 수준에서 충분이 제작이 가능한 것이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.177-178
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• 2011

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.79-85
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• 2016

Truing process is a very important process for recovering the shape of wheels worn by continuous grinding operation. In this study, the devices, controller, and spindle for electro-discharge truing were developed, and the electro-discharge truing method was applied to metal-bonded grinding wheels and compared with the conventional truing method. The shapes of the grinding wheels were measured by a surface profile measurement device. The protrusion of abrasives on the surface of the wheels was compared with the conventional truing method using an optic microscope measurement device. The experimental results showed that the performance of the electro-discharge truing method, in terms of the protrusion of abrasives on the surface of the wheels and the recovery of the shape of the worn wheels, was similar to that of the conventional truing method.