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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Mechanical Engineers A
Journal Basic Information
Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 37, Issue 12 - Dec 2013
Volume 37, Issue 11 - Nov 2013
Volume 37, Issue 10 - Oct 2013
Volume 37, Issue 9 - Sep 2013
Volume 37, Issue 8 - Aug 2013
Volume 37, Issue 7 - Jul 2013
Volume 37, Issue 6 - Jun 2013
Volume 37, Issue 5 - May 2013
Volume 37, Issue 4 - Apr 2013
Volume 37, Issue 3 - Mar 2013
Volume 37, Issue 2 - Feb 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Study of Hypervelocity Penetration Characteristics of Segmented Tungsten Penetrator
Jo, Jong Hyun ; Lee, Young Shin ; Kim, Jae Hoon ; Bae, Yong Woon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 953~960
DOI : 10.3795/KSME-A.2013.37.8.953
This study aimed to investigate the penetration characteristics of a segmented penetrator with normal and inclined angles. The length to diameter ratio (L/D) of the segmented penetrator was varied as 1.0, 0.5, and 0.25. Moreover, impact velocities of 1.5, 2.0, and 2.5 km/s and inclination angles of
were successively applied. The AUTODYN-3D code was used to simulate the penetration performance of the segmented penetrator. The results show that the penetration performance of the segmented penetrator with steel plates was obviously higher than that of the corresponding continuous penetrator with steel plates. The outstanding penetration performance of the segmented penetrator can be observed when the impact velocity was 2.0 km/s and L/D = 1. In this case, the penetration performance of the segmented penetrator was 7% higher than that of the corresponding continuous penetrator. This trend was attributable to the interaction between the reactive plate and the projectile. The extent of the interaction relies on the relative velocities of the plate and projectiles, inclination angle, and number of segmented penetrators. It was proven that the penetration performance of the segmented penetrator can be improved by increasing the impact velocity, number of segmented penetrators between segments, and penetrator length.
A Study on Prediction of Effective Seebeck Coefficient of Thermoelectric Composites Using Modified Eshelby Model
Lee, Jae-Kon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 961~966
DOI : 10.3795/KSME-A.2013.37.8.961
A coupled governing equation of thermoelectric materials can be converted into an uncoupled form to predict the effective Seebeck coefficient of thermoelectric composites, where modified Eshelby model is adopted. The predicted results by the present approach for serial- and parallel-connected composites and composite with spherical inclusions are compared with theoretical and experimental results from literatures to be justified. It is shown that the predictions by the theoretical approaches coincide exactly and show in good agreement with the experiments.
Technical Review of Specimens under Ultrasonic Fatigue Test
Myeong, No-Jun ; Han, Seung-Wook ; Park, Jung-Hoon ; Choi, Nak-Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 967~973
DOI : 10.3795/KSME-A.2013.37.8.967
An accelerated ultrasonic fatigue test(UFT) has been used for analyzing very high cycle fatigue( VHCF,
). This study reviews how the test specimen is to be determined. We focus on UFT using a resonance of 20 kHz. The specimen geometry is determined by selecting test materials by using a dynamic Young's modulus and wavelength of 20 kHz. The dynamic Young's modulus is calculated at the resonant frequency. Through a resonant vibration test at 20 kHz, the length of the specimen is calculated. By determining the shape of the specimen, the stress during the UFT is calculated. The UFT results should be comparable at the test frequency and the specimen geometry obtained by the conventional fatigue tests.
Solving Probability Constraint in Robust Optimization by Minimizing Percent Defective
Lee, Kwang Ki ; Park, Chan Kyoung ; Kim, Geun Yeon ; Lee, Kwon Hee ; Han, Sang Wook ; Han, Seung Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 975~981
DOI : 10.3795/KSME-A.2013.37.8.975
A robust optimization is only one of the ways to minimize the effects of variances in design variables on the objective functions at the preliminary design stage. To predict the variances and to formulate the probabilistic constraints are the most important procedures for the robust optimization formulation. Though several methods such as the process capability index and the six sigma technique were proposed for the prediction and formulation of the variances and probabilistic constraints, respectively, there are few attempts using a percent defective which has been widely applied in the quality control of the manufacturing process for probabilistic constraints. In this study, the robust optimization for a lower control arm of automobile vehicle was carried out, in which the design space showing the mean and variance sensitivity of weight and stress was explored before robust optimization for a lower control arm. The 2nd order Taylor expansion for calculating the standard deviation was used to improve the numerical accuracy for predicting the variances. Simplex algorithm which does not use the gradient information in optimization was used to convert constrained optimization into unconstrained one in robust optimization.
Performance Study of Diagonally Segmented Piezoelectric Vibration Energy Harvester
Kim, Jae Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 983~989
DOI : 10.3795/KSME-A.2013.37.8.983
This study proposes a piezoelectric vibration energy harvester composed of two diagonally segmented energy harvesting units. An auxiliary structural unit is attached to the tip of a host structural unit cantilevered to a vibrating base, where the two components have beam axes in opposite directions from each other and matched short-circuit resonant frequencies. Contrary to the usual observations in two resonant frequency-matched structures, the proposed structure shows little eigenfrequency separation and yields a mode sequence change between the first two modes. These lead to maximum power generation around a specific frequency. By using commercial finite element software, it is shown that the magnitude of the output power from the proposed vibration energy harvester can be substantially improved in comparison with those from conventional cantilevered energy harvesters with the same footprint area and magnitude of a tip mass.
Study of Improvement in Fatigue Life of Fuel Injection Pipe of Common Rail System
Song, Se Arm ; Bae, Jun Ho ; Jung, Sung Yuen ; Kim, Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 991~998
DOI : 10.3795/KSME-A.2013.37.8.991
The fuel injection pipe of a common rail system used in a clean diesel vehicle plays a role in supplying fuel from a rail to the injector of each cylinder connecting the engine under a repeated internal pressure. The fuel injection pressure is increased to over 200 MPa for satisfying EU emission standards and improving fuel efficiency, and a heading process and an autofrettage process are required for preventing folding defects and improving fatigue life. In this study, the flow stress and SN data of the material of the pipe are obtained through a tensile test and a fatigue test. The heading process for checking the folding defects of pipe ends is performed by using FEA. Furthermore, the optimal design of the autofrettage process for improving fatigue life considering not only the compressive residual stresses of the inner surface but also the tensile residual stresses of the outer surfaces of the pipe under the repeated internal pressure is performed by using FEA. To verify the process design, fatigue analysis for the autofrettaged pipe is performed.
Characteristics of Thermal Coefficient of Fiber Bragg Grating for Temperature Measurement
Kim, Heon-Young ; Kang, Donghoon ; Lee, Jin-Hyuk ; Kim, Dae-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 999~1005
DOI : 10.3795/KSME-A.2013.37.8.999
A fiber Bragg grating sensor is considered a smart sensor that shows outstanding performance in the field of structural health monitoring (SHM). It has a powerful advantage, especially that of multiplexing, which enables several parameters to be sensed at multiple points by using a single optical fiber line. Among several parameters, the thermal expansion coefficient and thermo-optic coefficient are required to measure temperature. In previous studies, these were considered constant variables. This study shows that two parameters vary with temperature and newly proposes a temperature function for these two parameters. Specifically, these two parameters were defined as a single variable, and then, it was experimentally verified that this variable is a function of temperature. Finally, it was shown that temperature from RT to
was precisely measured by using the temperature function that was defined through the experiment.
Numerical Study of Aerodynamics of Turbine Rotor with Leading Edge Modification Near Hub
Kim, Dae Hyun ; Lee, Won Suk ; Chung, Jin Taek ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1007~1013
DOI : 10.3795/KSME-A.2013.37.8.1007
This study aims to analyze the aerodynamics when the geometry of the turbine rotor is modified. The turbine used in this study is a small engine used in the APU of a helicopter. It is difficult to improve the performance of small engines owing to the structural weakness of the blade tip. Therefore, the improvement of the hub geometry is investigated in many ways. The working fluid of a turbine is a high-temperature and high-pressure gas. The heat transfer rate of the turbine surface should be considered to avoid the destruction of blade owing to the heat load. The SST turbulence model gives an excellent prediction of the aerodynamic behavior and heat transfer characteristics when the numerical simulations are compared with the experimental results. In conclusion, the aerodynamic efficiency is improved when a bulbous design is applied to the leading edge near the hub. The endwall loss is reduced by 15%.
Lightweight Suspension Module Development for Electric Vehicle
Jung, Yoon-Sik ; Shin, Heon-Seop ; Rhim, Sungsoo ; Choi, Jin-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1015~1019
DOI : 10.3795/KSME-A.2013.37.8.1015
To improve the energy efficiency and ride quality of an electric vehicle, it is highly desirable to develop a lightweight suspension system with high travel ratio. Air suspension systems with a rubber tube are often considered optimal for such requirements. In this study, a new lightweight air suspension system with high travel ratio was developed for use in electric vehicles. Furthermore, an FE-based multi-flexible-body dynamics (MFBD) model of the suspension system was developed as a tool for improving the design of an actual suspension system. The MFBD model includes the FE modeling of the rubber tube module as well as other essential parts of the air suspension system. The system parameters for the model were obtained from various experiments. The validity of the developed MFBD model was shown through a comparison between the experimental results and the simulation results.
Prognostic Technique for Pump Cavitation Erosion
Lee, Do Hwan ; Kang, Shin Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1021~1027
DOI : 10.3795/KSME-A.2013.37.8.1021
In this study, a prognostic technique for cavitation erosion that is applicable to centrifugal pumps is devised. To estimate the erosion states of pumps, damage rates are calculated based on cavitation noise measurements. The accumulated damage is predicted by using Miner's rule and the estimated damage undergone when coping with particular operating conditions. The remaining useful life (RUL) of the pump impellers is estimated according to the accumulated damage prediction and based on the assumption of future operating conditions. A Monte Carlo simulation is applied to obtain a prognostic uncertainty. The comparison of the prediction and the test results demonstrates that the developed method can be applied to predict cavitation erosion states and RUL estimates.
A Study on the Elliptical Gear Design for Oval flowmeter
Park, Jin Joo ; Lee, Eung Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1029~1033
DOI : 10.3795/KSME-A.2013.37.8.1029
Elliptical gear is used as a rotor of oval flowmeter. The elliptical gear can assist water flow-rate measurement by the space of the elliptical shape. Presently, elliptical gears have been processed using hob tool imported from Japan. But if it were not for the technical cooperation with Japan company, the Elliptical gears can't be processed. The purpose of this study is developing a domestic technology for elliptical gears and overcoming the dependence of foreign technical skills. It will bring the import substitution effect. In case of pressure angle
, the elliptical gears have an interference of tooth. The increase of pressure angle makes the root of a tooth thick and the top of tooth thin. By results of this study, tooth of elliptical gear was designed and verified through the 2D and 3D simulation.
Study on Structural Integrity and Dynamic Characteristics of Knuckle Parts of KTX Anti-Roll Bar
Jeon, Kwang Woo ; Shin, Kwang Bok ; Kim, Jin Woo ; Jeong, Yeon Il ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1035~1041
DOI : 10.3795/KSME-A.2013.37.8.1035
To evaluate the structural integrity and dynamic characteristic of the knuckle part of a KTX anti-roll bar, an experimental and a numerical approach were used in this study. In the experimental approach, the acceleration and strain data for the knuckle parts of the KTX and KTX-SANCHUN anti-roll bar were respectively measured to evaluate and compare its structural dynamic characteristics under the operating environments of the Honam line. In the numerical approach, the evaluation of its structural integrity was conducted using LS-DYNA 3D, and then, the reliability of the finite element model used was ensured by a comparative evaluation with the experiment. The numerical results showed that the stress and velocity field of the knuckle part composed of a layered structure of a thin steel plate and rubber were more moderate than those of the knuckle part made of only a thick steel block owing to the reduction of relative contact between the knuckle and the connecting rod. It was found that the knuckle part made of a thin steel plate and rubber was recommended as the best solution to improve its structural integrity resulting from the elastic behavior of the KTX anti-roll bar being enabled under a repeating external force.
Development of Industrial High-Speed Transfer Parallel Robot
Kim, Byung In ; Kyung, Jin Ho ; Do, Hyun Min ; Jo, Sang Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1043~1050
DOI : 10.3795/KSME-A.2013.37.8.1043
Parallel robots used in industry require high stiffness or high speed because of their structural characteristics. Nowadays, the importance of rapid transportation has increased in the distribution industry. In this light, an industrial parallel robot has been developed for high-speed transfer. The developed parallel robot can handle a maximum payload of 3 kg. For a payload of 0.1 kg, the trajectory cycle time is 0.3 s (come and go), and the maximum velocity is 4.5 m/s (pick amp, place work, adept cycle). In this motion, its maximum acceleration is very high and reaches approximately 13g. In this paper, the design, analysis, and performance test results of the developed parallel robot system are introduced.
Measurement of Surface Strain on Soft Biological Tissues Using Irregular Grid Pattern
Lee, Jun Sik ; Kim, Ki Hong ; Kim, Hyung Jong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1051~1057
DOI : 10.3795/KSME-A.2013.37.8.1051
In this study, an automatic surface-strain measurement system called "ASIAS-bio" has been developed. This system can be used even in cases in which it is very difficult to apply a regular grid pattern necessary for measuring surface-strain, such as curved or uneven surfaces; surfaces damaged by corrosion or contamination; or soft materials such as rubber, foam, and biological tissues. This system works independently of the measurement conditions including the material and its surface condition, grid pattern and size, grid marking method, and degree of deformation. A comparison between the strain distributions of the sheet metal parts measured by using this system and those obtained by a commercial system showed that this system was sufficiently reliable. In addition, the deformation of the swine joint capsule and human knee skin was measured by using this system to demonstrate its usefulness.
Design of Automotive Fuel Tank for Preventing Liquid Carry Over Using Taguchi Method and Approximate Optimization
Park, Gyu-Byung ; Lee, Yongbin ; Cho, In-Geun ; Choi, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 8, 2013, Pages 1059~1067
DOI : 10.3795/KSME-A.2013.37.8.1059
Automotive fuel tank is generally divided into two parts: main frame and assembly parts. While the car is running, valves are used to prevent liquid carry over and to discharge evaporated gas from the fuel tank. However, current fuel tank designs focus on the gas ventilation or secured location. In this study, the location of the parts used to prevent liquid carry over within the fuel tank is evaluated during an optimal design process. To develop this design process, an approximate optimization is applied. Through the optimal design process, the optimal valve location in fuel tank is determined and the approximate optimization is validated by the Taguchi method. Finally, the optimized valve location is used to reduce the development cost and time and to contribute toward improved automobile quality owing to enhanced reliability.