• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.316-323
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• 2003

The gear system is commonly applied in the marine propulsion shafting system using the diesel engine with the power take off/in system and it also is necessary to reduce propeller revolution increasing the propulsion efficiency. The diesel engine has the advantage more than other thermal engines in high thermal efficiency and mobility. But the large vibratory torque which induced by higher combustion pressure is transmitted to these gears. In this paper, the surface durability and bending stress of gear system considering vibratory and transient torque is evaluated by ISO and AGMA regulation. And the influence of these in gear design is investigated with the theoretical analysis and onboard measurement result of torsional vibration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.868-874
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• 2011

In this paper, a new structure to improve the resolution of an inductive torque sensor is proposed. The new coupling structure and the change of number of turns for the receiving coil increase the resolution of the torque sensor. Because this torque sensor has non-contact points, it has no abrasion at the contact point, and is very durable. Also, the torque sensor has less variation due to vibration or strain, and it has a good EMC(Electromagnetic Compatibility) and thermal characteristics.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.65-70
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• 2012

Torque fluctuation of engine generate gear rattle noise of transmission and many researches have been studied to decrease rattle noise by adjusting clutch damper system. So design optimization of clutch system is very important to decrease rattle noise and need knowing clutch dynamic torque at real vehicle driving condition. This makes it possible to measure clutch dynamic torque by using a small-size magnetic sensor. We install a small-size magnetic sensor on the input shaft of the transmission and measure the relative angular displacement between clutch hub and disc plate. We can obtain the clutch torque correspond to the angular displacement in the clutch torsional characteristics test. The object of this research is to measure clutch dynamic torque on real vehicle condition. Therefore, Clutch dynamic torque is very useful for investigating operating range of clutch according to engine torque and predicting the damping performance of torsional vibration on the powertrain.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.5
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• pp.645-649
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• 2010

Induction hardening has been used to improve the torsional strength and characteristics of wear for axle shaft that is used to transmit driving torque from the differential to the wheel in automobiles. After the rapid heating and cooling processes of induction hardening are carried out, the shaft has residual stress and material properties change; this affects the allowable transmitted torque. The objective of this study is to predict the distribution of residual stress and estimate the torsional strength of induction-hardened axle shafts with residual stress. In this study, the finite element method is used to study the thermomechanical behavior of the material, and the results are compared with experimental results. The results indicate that the torsional strength of the axle shaft depends on the surface hardening depth and distribution of residual stress.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.437-442
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• 2014

The equipment or with a constant torque and a variable stress due to axial vibration such as the turbine-generator system in nuclear power plant show the fatigue fracture behavior. Thus this study whoul aim to measure the torsional stress and analyze the fatigue fracture behavior. To achieve this, we manufactured the equipment similar with turbine-generator system and applied various torsional vibration stress due to external load. In particular, the evaluation was conducted with the existing evaluation methods of the fatigue behavior of known stress-life, strain-life, crack growth assessment methods. With increasing the external load and independent methods tends to decrease the fatigue life was confirmed up to 10 times in 5 kV external load compared to without external load.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.567-573
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• 2017

The drive shaft of passenger vehicle has an important role in transmitting the torque between the power train system and the wheels. Torsional fatigue failures occur generally in the connection parts of the spline edge of the drive shaft, when there is significant fatigue damage under repeated twisting loads. A heat treatment, an induction hardening process, has been adopted to increase the torsional strength as well as the fatigue life of the drive shaft. However, it is still unclear how the extension of the induction hardening process in a used material relates to its shear-strain fatigue life range. In this study, a shear-strain controlled torsional-fatigue test with a specially designed specimen was conducted by an electro-dynamic torsional fatigue test machine. A finite element analysis of the drive shaft was carried out using the results obtained by the fatigue experiment. The estimated fatigue life was verified through a twisting load test of the real drive shaft in a test rig.

• Composites Research
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• v.14 no.2
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• pp.13-21
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• 2001

Substituting composite structures for conventional metallic structures has many advantages because of higher specific stiffness and specific strength of composite materials. In this work, one-piece driveshafts composed of carbon/epoxy and glass/epoxy composites were designed and manufactured for a rear wheel drive automobile satisfying three design specifications, such as static torque transmission capability, torsional buckling and the fundamental natural bending frequency. Single lap adhesive joint was used to join the composite shaft and the aluminum yoke. The torque transmission capability of the adhesively bonded composite shaft was calculated with respect to bonding length and yoke thickness by finite element analysis and compared with the experimental result. Torque transmission capability was based on the Tsai-Wu failure index fur composite shaft and the failure model which incorporated the nonlinear mechanical behavior of aluminum yoke and epoxy adhesive. From the experiments and the finite element analyses, it was found that the static torque transmission capability of the composite driveshaft was highest at the critical yoke thickness, and saturated beyond the critical length. Also, it was found that the one-piece composite driveshaft had 40% weight saving effect compared with a conventional two-piece steel driveshaft.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.221-228
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• 1999

A full-time four wheel drive vehicle is driven literally full time by the front and the rear wheels. Front and rear drive shafts are rotated rapidly in the extremely torsional state, which can cause various vibration and noise problems. The purpose of this study is to reduce the vibration and the noise of the full -time four wheel drive vehicle. In this paper, both the causes and the methods for reduction of torsional vibration are suggested. For this study, the characteristics of the torsional vibration are analyzed by free and forced torsional vibration simulation. And this paper described the influence upon the torsional vibration with emphasis shafting system. The validity of simulation models is checked by the field test. The forced vibration simulation with the variations of shaft design factors are performed by the checked models. According to the simulation , the resonance region shifts and the torque fluctuation varies in the system,. Finally, the methods and the effects for the torsional vibration reduction in driveline are proposed.

• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.131-140
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• 2003

The purpose of this study was to evaluate clinical applications of electroplating method through investigation of the physical properties of orthodontic rectangular wires according to varying their cross section. For the study, it was accomplished to electroplate the 0.016-inched orthodontic rectangular stainless steel wire. The cross section of stainless steel orthodontic rectangular wire increased from $0.016{\times}0.016inch\;to\;0.017{times}0.017inch$ by electroplating. The wire was heat treated to improve an adhesion between the wire and electroplated metal. h three-point bending test and torsion test were conducted in order to compare physical properties among three wire groups; $0.016{\times}0.016wires(group 016),\; electroplated\;0.016{\times}0.016wires(group\;016P)\;and\;0.017{\times}0.017$ wires (group 017). Through the investigations of each wire group, following results were obtained 1. At three-point bending test, the group Ol6P showed higher tendency in the degree of stiffness, yield strength and ultimate tensile strength than the group 016. Stiffness and ultimate tensile strength showed statistically significant differences between two groups at three-point bending test (p<0.05). 2. Stiffness, yield strength, and ultimate tensile strength of the group 016P showed lower tendency than those of the group 017 Stiffness showed statistically significant differences between two groups at three-point bending test (p<0.05). 3. Torque/twist rate, yield torsional moment, and ultimate torsional moment of the group 016P showed higher tendency than those of the group 016. All measurements showed statistically significant differences between two groups alter torsion test (p<0.05). 4. Torque/twist rate, yield torsional moment, and ultimate torsional moment of the group 0166P showed lower tendency than those of the group 017. Yield torsional moment, and ultimate torsional moment showed statistically significant differences between two groups after torsion test (p<0.05).

• Journal of KSNVE
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• v.10 no.3
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• pp.465-473
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• 2000

In this crankshaft of marine diesel engines the exciting torques are produced by gas pressure and reciprocating masses. These torques are periodically changing and are extremely out of balance. To calculate the torsional vibrations of propulsion shafting caused by unbalanced torque the torque harmonics are utilized. Until now to calculate the torsional vibrations of propulsion shafting. the torque harmonics have been supplied by the engine maker. When the torque harmonics of an engine are not available the torque harmonics of a similar engine type had to be used. However such data is not suitable for the reliable calculations of torsional vibrations. In this paper the combustion characteristics of marine diesel engines including $\rho{-}\upsilon$ diagram are investigated and the torque harmonics based on these are theoretically calculated. reliability of the calculations is confirmed by comparing them with those of an engine maker. This study should prove useful for the calculations of torsional vibrations for diesel engine propulsion shafting. particularly for 4-stroke engines whose torque harmonics are difficult to obtain directly from the engine and not ordinarily supplied by the engine maker.