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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 35, Issue 12 - Dec 2011
Volume 35, Issue 11 - Nov 2011
Volume 35, Issue 10 - Oct 2011
Volume 35, Issue 9 - Sep 2011
Volume 35, Issue 8 - Aug 2011
Volume 35, Issue 7 - Jul 2011
Volume 35, Issue 6 - Jun 2011
Volume 35, Issue 5 - May 2011
Volume 35, Issue 4 - Apr 2011
Volume 35, Issue 3 - Mar 2011
Volume 35, Issue 2 - Feb 2011
Volume 35, Issue 1 - Jan 2011
Selecting the target year
A Preliminary Study on the Optimal Shape Design of the Axisymmetric Forging Component Using Equivalent Static Loads
Jung, Ui-Jin ; Lee, Jae-Jun ; Park, Gyung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 1~10
DOI : 10.3795/KSME-A.2011.35.1.001
An optimization method is proposed for preform and billet shape designs in the forging process by using the Equivalent Static Loads (ESLs). The preform shape is an important factor in the forging process because the quality of the final forging is significantly influenced by it. The ESLSO is used to determine the shape of the preform. In the ESLSO, nonlinear dynamic loads are transformed to the ESLs and linear response optimization is performed using the ESLs. The design is updated in linear response optimization and nonlinear analysis is performed with the updated design. The examples in this paper show that optimization using the ESLs is useful and the design results are satisfactory. Consequently, the optimal preform and billet shapes which produce the desired final shape have been obtained. Nonlinear analysis and linear response optimization of the forging process are performed using the commercial software LS-DYNA and NASTRAN, respectively.
Power Control of MW Wind Turbine
Nam, Yoon-Su ; Kim, Jeong-Gi ; Choi, Han-Soon ; Cho, Jang-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 11~15
DOI : 10.3795/KSME-A.2011.35.1.011
In this paper, a methodology for the power control of a wind turbine, which is the variable-speed and variable-pitch (VSVP) control system, is introduced. This control methodology maximizes the capability of the turbine to extract maximum power from the wind in the regions with low wind speeds. Further, it regulates the wind-turbine power as the rated power in the case of the regions with high wind speeds. A simple drive train model is used to design the VSVP control system. The methodology for VSVP control is mechanized by controlling the generator torque and blade pitch. Finally, some simulation results for the VSVP control to a MW wind turbine are discussed in this paper.
Torsional Vibration Control of a Rotating Chamber Shaft System Using Electrorheological Fluid
Lim, Seung-Chul ; Kim, Ki-Kap ; Kil, Seong-Jin ; Shim, Jeong-Soo ; Cha, Ki-Up ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 17~24
DOI : 10.3795/KSME-A.2011.35.1.017
It is reported that an intermittently rotating chamber system will improve the ratio of firepower to armament space in the case of mid-calibre automatic guns. However, the parallel index, which is a main component of the system, tends to be torsionally flexible due to the low lateral stiffness of cam followers on the index turret. This may cause the shaft system connecting the turret with the chamber prone to considerable residual torsional vibration so that serious misalignment problems occur during ammunition loading and firing processes. Herein, an electrorhelogical (ER) fluid actuator that can suppress such vibrations and the associated semiactive control algorithm are proposed. By mathematical modeling and computer simulations, the performance of the entire system is proved satisfactory.
True Stress-True Strain Curves Obtained by Simulating Tensile Tests Using Finite Element Program
Chu, Seok-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 25~31
DOI : 10.3795/KSME-A.2011.35.1.025
In the tensile test necking occurs at the maximum load point and non-uniform stress state is generated in this section. The equivalent stress becomes quite different from the axial stress as necking proceeds. Methods for obtaining the true stress-true strain curves, by overcoming difficulties due to the necking phenomena, have been developed by many authors. One of the methods based on the finite element analysis simulation is a very promising method. In this paper, general-purpose finite element program is used to simulate the tensile test. A round specimen and a flat specimen prepared from the same steel block are tested and simulated. The true stress-true strain curves are determined without assuming that the material follows Hollomon's law.
Improving Dimensional Accuracy of Micropatterns by Compensating Dynamic Balance of a Roll Mold
Lee, Dong-Yoon ; Hong, Sang-Hyun ; Song, Ki-Hyeong ; Kang, Eun-Goo ; Lee, Seok-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 33~37
DOI : 10.3795/KSME-A.2011.35.1.033
In the fields of display, optics, and energy, it is important to improve micropattern-machining technology for achieving small patterns, large surface areas, and low cost. Unlike flat molds, roll molds have the following advantages: they can be manufactured within a short time, larger surface areas can be obtained, and continuous molding can be achieved. In this study, we aim to investigate the causes for errors in the shapes for a micropattern-machining process, and we show that by compensating the dynamic balance of roll molds, the dimensional accuracy of machined parts can be improved. The experimental results show that dynamic-balance compensation for a roll mold reduced the mass unbalance and the vibrations of the roll mold, and as a result, the dimensional accuracy of machined micropatterns has been improved.
Design of Information Acquisition System for Equipments on Shop Floor
Lee, Jai-Kyung ; Lee, Seung-Woo ; Nam, So-Jeong ; Park, Jong-Kweon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 39~45
DOI : 10.3795/KSME-A.2011.35.1.039
The processes for manufacturing a product differ depending on the characteristics of the product, and the information used or generated by the processes also varies. To implement a flexible and configurable Manufacturing Execution System (MES), a Data Acquisition System (DAS) that takes into consideration the characteristics of the manufacturing system is required. In this study, we design an information acquisition system that can process the information on equipments of a shop floor in real-time and that is adaptive to the changes in the shop floor. The system has a data parser module for flexible processing of the equipment status, a data mapper module to link the equipment status with a manufacturing process, and an SOA-based data integration module to transmit the processed information to other information systems such as MES and ERP. From the results of pilot study, its maintenance is easy even if new equipment or new manufacturing processes are adopted or if the equipments are rearranged.
Development of Model for Seismic Qualification of Electronic Enclosure for Nuclear Power Plant
Sur, Uk-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 47~52
DOI : 10.3795/KSME-A.2011.35.1.047
In this paper, we describe the development of a finite-element model for seismic qualification. This paper presents finite-element analysis model of the electronic enclosure to be used at Arkansas nuclear power plant, USA. The verified model predicts natural frequencies within 5% error for all major modes below 50 Hz. The finite element lumped mass approach and the finite element stiffness approach using the COSMOSM finite element code is applied for static, eigenvalue, and dynamic analyses of the mathematical model of this system. The FEM model indicates that the stress levels corresponding to the specified loading conditions are below the allowable stress levels that have been specified in the AISC Code. The findings conclude that the electronic enclosure will withstand the seismic levels stated in the reference documents.
Measurement of Geometric Errors of an Ultra Precision mMT Using PSDs
Kwon, Seol-Ryung ; Kweon, Sung-Hwan ; Yang, Seung-Han ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 53~58
DOI : 10.3795/KSME-A.2011.35.1.053
Ultra-precision miniaturized machine tools essential for manufacturing accurate machine components in micro/meso-scale have been developed. To realize high accuracy using mMTs, geometric errors, which are considered as the main sources of inaccuracy should be identified and compensated. The conventional systems for measuring geometric errors, such as a laser interferometer, can measure only one geometric error in a single setup and they involve complicated measurement procedures. A measurement system using PSDs is a promising alternative but the measurable range of such systems is limited to the active range of the PSDs. The proposed measurement system using PSDs can overcome the limit of small measurable range. Further, the mounting errors that could occur during set-up process can be avoided. In this paper, an algorithm corresponding to the system was analyzed and experiments were carried out.
Study on Properties of Pitch Control for Wind Turbine
Lim, Chae-Wook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 59~65
DOI : 10.3795/KSME-A.2011.35.1.059
The aerodynamic power and torque of wind turbines are extremely nonlinear. Therefore, the overall dynamic behavior of a wind turbine exhibits nonlinear characteristics that are dependent on the magnitude of the wind speed. The nonlinear aerodynamic characteristics of the wind turbine also affect the characteristics of the control system of the wind turbine. Therefore, the analysis of the nonlinear aerodynamic characteristics of wind turbine is essential in designing the wind-turbine controller. In this study, the nonlinear aerodynamic characteristics and the effects of these characteristics on the closed-loop pitch system with PI controller for an 1-mass model of the wind turbine are investigated above rated power.
Design of S-Shaped Path and Velocity Profile of Moving Stage Using Three Point Locations
Jung, Kwang-Oh ; Oh, Se-Kyu ; Kim, Dong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 67~76
DOI : 10.3795/KSME-A.2011.35.1.067
An exact curved path has to be fixed and velocity profile for travelling on the curved path is required by a moving stage. In this study, we decide the curved path on the basis of the information on three point locations. The path of the moving stage is traced by simulating the designed curve path and the velocity profile, and the results are compared with the given three points to determine how closely the moving stage follows the given path. Further, we propose a method to calibrate a curved path and velocity profile. The proposed moving paths were evaluated by performing experiments. Finally, the designed curved path and the actual path were compared.
Analysis of Dynamic Behavior of Floating Offshore Wind Turbine System
Jang, Jin-Seok ; Sohn, Jeong-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 77~83
DOI : 10.3795/KSME-A.2011.35.1.077
In this study, the dynamic modeling of floating offshore wind turbine system is reported and the dynamic behavior of the platform for the offshore wind turbine system is analyzed. The modeling of the wind load for a floating offshore wind turbine tower is based on the vertical profile of wind speed. The relative Morison equation is employed to obtain the wave load. ADAMS is used to carry out the dynamic analysis of the floating system that should withstand waves and the wind load. Computer simulations for four types of tension leg platforms are performed, and the simulation results for the platforms are compared with each other.
Study on Experimental Equipment for Anti-Skid Control Logic Test
Kim, Ho-Yeon ; Kang, Chul-Goo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 85~90
DOI : 10.3795/KSME-A.2011.35.1.085
To maintain the safety and efficiency of railroad vehicles, it is important to understand the working of the brake system with anti-skid control unit (ASCU) for rolling stocks. In this paper, a HILS (Hardware In-the Loop Simulations) system with ASCU hardware (for logic) and a DSP board (for dynamics) is developed to analyze skidding of the Hanvit-200 train during the process of braking. Experimental results are presented for the case that the skid on one of the four wheels is artificially generated using a Simulink model. A convenient GUI is prepared using ControlDesk of dSPACE.
Measurement of Aerodynamic Loads on Railway Vehicles Under Crosswind
Kwon, Hyeok-Bin ; You, Won-Hee ; Cho, Tae-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 91~98
DOI : 10.3795/KSME-A.2011.35.1.091
In this study, we measure the aerodynamic forces acting on an AREX train in a crosswind by wind tunnel testing. A detailed test model scaled to 5% of the original and including the inter-car, under-body, and the bogie systems was developed. The aerodynamic forces on the train vehicles have been measured in a 4 m
3 m test section of the subsonic wind tunnel located in Korea Aerospace Research Institute (KARI). The aerodynamic forces and moments of the train model on two different track models have been plotted for various yaw angles, and the characteristics of the aerodynamic coefficients have been analyzed at the experimental conditions.
Dynamic Analysis of Catenary System Subjected to Moving Load
Lee, Kyu-Ho ; Cho, Yong-Hyun ; Chung, Jin-Tai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 99~106
DOI : 10.3795/KSME-A.2011.35.1.099
In this study, the dynamic contact of a catenary system is analyzed by using the finite element method. We derive the equations of motion for the catenary system by taking into consideration tension on the catenaries. After establishing the weak form, they are spatially discretized with beam elements. Then, we analytically calculated the wave propagation speed for a string, bar, beam, and the catenaries subjected to tension. Further, finite element computer program for contact dynamic analyses is developed. Finally, we analyze the wave propagation response corresponding to the moving load to the contact line are calculated.
Study on Experimental Modeling and Estimation of Roughness of Nanoscale Lapping Surface Based on Laser Scattering Patterns
Hong, Yeon-Ki ; Kim, Gyung-Bum ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 107~114
DOI : 10.3795/KSME-A.2011.35.1.107
In this study, a correlation between the roughness of nanoscale lapping surface and its laser scattering pattern has been identified experimentally. The characteristics of laser scattering on a reflected surface are investigated, and a laser scattering mechanism is newly designed by adopting the dark-field method. Laser scattering patterns resulting from nanoscale lapping shape are in the shape of crossed irregular lattice. In addition, optimum laser scattering images are obtained by the design of experiment, and the roughness of nanoscale lapping surface is estimated using regression analysis certain useful features of the laser scattering patterns. The results of fifty experiments on three types of nanoscale lapping surfaces show that the roughness of nanoscale lapping surfaces can be accurately estimated by the proposed mathematical modeling method.
Modeling of Multi-Boom Floating Crane for Lifting Analysis of Offshore Wind Turbine
Park, Kwang-Phil ; Cha, Ju-Hwan ; Lee, Kyu-Yeul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 1, 2011, Pages 115~120
DOI : 10.3795/KSME-A.2011.35.1.115
The dynamic responses of a 5 MW wind turbine lifted by a floating crane with two elastic booms are analyzed. Dynamic equations of motions of a multibody system that consists of a floating crane, two elastic booms, and a wind turbine are derived. The six-degree-of-freedom (DOF) motions for the floating crane and the wind turbine are considered in the equations of motions. The hydrostatic force, the hydrodynamic force due to a regular wave, the mooring force, the wire rope force, and the gravitational force are considered as external forces. By solving the equations numerically, the dynamic responses of cargo are simulated. The simulation results are compared with those in the case of one elastic boom. Finally, the dynamic responses of the wind turbine lifted by the floating crane are analyzed under regular wave condition.