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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
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 27, Issue 12 - Dec 2003
Volume 27, Issue 11 - Nov 2003
Volume 27, Issue 10 - Oct 2003
Volume 27, Issue 9 - Sep 2003
Volume 27, Issue 8 - Aug 2003
Volume 27, Issue 7 - Jul 2003
Volume 27, Issue 6 - Jun 2003
Volume 27, Issue 5 - May 2003
Volume 27, Issue 4 - Apr 2003
Volume 27, Issue 3 - Mar 2003
Volume 27, Issue 2 - Feb 2003
Volume 27, Issue 1 - Jan 2003
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Friction Transition Diagram Considering the Effects of Oxide Layer Formed on Contact Parts of TiN Coated Ball and Steel Disk in Sliding
Cho, Chung-Woo ; Park, Dong-Shin ; Lee, Young-Ze ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 335~342
DOI : 10.3795/KSME-A.2003.27.3.335
In this study, the effects of oxide layer formed on the contact parts of TiN coated ball and steel disk in sliding are investigated. Also wear mechanism to from the oxide layer and the characteristics of the oxide layer formation are investigated. AISI 52100 steel ball is used for the substrate of coated ball specimens. Two types of coated ball specimens were prepared by depositing TiN coating with 1 and 4
in coating thickness. AISI 1045 steel is used for the disk type counter-body. To investigate the effect of oxide layer on the contact parts of the two materials, the tests were performed both in air for forming oxide layer on the contact parts and in nitrogen environment to avoid oxidation. And to study the effects of surface roughness of counter-body, TiN coating thickness and contact load of sliding test on the characteristics of oxide layer formation on counter-body, various tests were carried out. From the results, the friction characteristics between the two materials was predominated by iron oxide layer that formed on wear track on counter-body and this layer caused the high friction. And the formation rate of the oxide layer on wear track increased as the real contact area between the two materials increased as the contact load increased, the TiN coating thickness decreased and the surface of counter-body smoothened.
An Optimization of Air-Lubricated Slider Bearings Using the Reduced Basis Concept
Yoon, Sang-Joon ; Kim, Dong-In ; Kang, Tae-Sik ; Jeong, Tae-Gun ; Choi, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 343~348
DOI : 10.3795/KSME-A.2003.27.3.343
In this study, optimum designs of the air-bearing surface (ABS) are achieved using the reduced basis concept which can effectively reduce the number of design variables without cutting down on the design space. Even though the optimization method is easier and more applicable to handle than the trial-and-error method, its efficiency is largely dependent on the number of the design variables. Hence, the reduced basis concept is applied, by which the desired design can be defined as a linear combination of basis designs. The simulation results show the effectiveness of the proposed approach by obtaining the optimum solutions of the sliders whose target flying heights are 25, 20, and 15nm.
Eviction Characteristics of Piston Assembly (I) -Theory-
Cho, Myung-Rae ; Ha, Kyoung-Pyo ; Kim, Joong-Soo ; Oh, Dae-Yoon ; Han, Dong-Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 349~356
DOI : 10.3795/KSME-A.2003.27.3.349
The aim of this paper is to investigate the friction characteristics of piston assembly. The friction of piston assembly is composed of ring pack and skirt friction. In this paper, the theoretical models of piston ring pack and piston skirt were presented. The mixed lubrication theory was considered to calculate friction force of piston ring and skirt. from the results, most of friction in piston assembly occurred at the piston ring park. The piston assembly usually showed hydrodynamic lubrication characteristics. but the top and bottom dead centers showed mixed lubrication characteristics. The piston skirt was much affected by radial clearance and load, but ring was significantly influenced by ring tension.
Ultrasonic Vibration Machining of Inconel
Park, Myung-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 357~362
DOI : 10.3795/KSME-A.2003.27.3.357
Recently, the demand for advanced technology of high precision and high efficiency processing of hard materials such as inconel is increasing with progress of industrial goods. However, the machinability of inconel is very inferior to the other conventional industrial materials and the machining technology for inconel involves many problems to be solved in machining accuracy, machining efficiency, etc. Therefore it is needs to establish the machining technology. The purpose of this study is to develop an advanced ultrasonic vibration machining technology for inconel, using the 60KHz and 75KHz high frequency, amplitude about 8
, respectively. As the result, this new ultrasonic vibration machining is reasonable and suitable for the high efficient. accuracy machining method of inconel.
Cavitation-Erosion Characteristics between Polymer Based Composites and Metals under the Various Condition of Fluid Systems
Kim, Yun-Hae ; Son, Young-Jun ; Eum, Soo-Hyun ; Lee, Jung-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 363~371
DOI : 10.3795/KSME-A.2003.27.3.363
This study is mainly concerned with phenomenon of cavitation-erosion on the several materials and corrosive liquids which were applied with vibrator(suggested by ASTM G 32, 20KHz, 50
). The maximum erosion rate by cavitation erosion in both of distilled water and sea water appeared to be proportioned to their hardness and tensile strength. Cavitation weight loss and rate of cast iron in sea water condition were greater(approximately 3 times) than that in distilled water condition, however in case of stainless steel and brass the cavitation weight loss of composite materials were not so different in both of their conditions. Cavitation weight loss of composite materials were shown as below on this test, Duratough DL : Weight loss in sea-water condition were greater (approximately 2.3 times) than it`s distilled water condition. The main tendency of cavitation erosion for metals appeared that small damaged holes causing by cavitation erosion was observed with radial pattern. On the other hand, the tendency for composites appeared that small damaged holes were observed randomly.
Effect of Fiber Orientation Angle and Property of Metal Laminate on Impact Behaviors of Fiber Metal Laminates
Nam, Hyun-Wook ; Jung, Sung-Wook ; Han, Kyung-Seop ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 372~380
DOI : 10.3795/KSME-A.2003.27.3.372
Impact tests were conducted to study the effect of angle ply and metal laminate on impact damage characteristics of Fiber Metal laminates (FML). Impact tests were conducted using drop weight impact machine and damage behavior were analyzed by comparing with load-displacement curve and surface observation and microscopic observation of cross sections. The effect of angle ply on impact characteristics of FML are influenced by property of metal laminate. i.e., when the metal laminate is not enough to strong to prevent fiber debonding, Angle ply FML is superior to singly oriented ply (SOP) FML because angle ply enhance the stiffness by fiber supports and prevent (rack propagation. However, when the metal laminate is enough to strong to prevent fiber debonding, SOP FML is superior to Angle ply FML because the fiber of lower ply in Angle ply FML are more stressed than that of SOP FML.
Shape Optimization of a CRT based on Response Surface and Kriging Metamodels
Lee, Tae-Hee ; Lee, Chang-Jin ; Lee, Kwang-Ki ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 381~386
DOI : 10.3795/KSME-A.2003.27.3.381
Gradually engineering designers are determined based on computer simulations. Modeling of the computer simulation however is too expensive and time consuming in a complicate system. Thus, designers often use approximation models called metamodels, which represent approximately the relations between design and response variables. There arc general metamodels such as response surface model and kriging metamodel. Response surface model is easy to obtain and provides explicit function. but it is not suitable for highly nonlinear and large scaled problems. For complicate case, we may use kriging model that employs an interpolation scheme developed in the fields of spatial statistics and geostatistics. This class of into interpolating model has flexibility to model response data with multiple local extreme. In this study. metamodeling techniques are adopted to carry out the shape optimization of a funnel of Cathode Ray Tube. which finds the shape minimizing the local maximum principal stress Optimum designs using two metamodels are compared and proper metamodel is recommended based on this research.
The Effect of the Area Ratio and the Distance Ratio on Bending Stiffness of Two Rectangular Spot-Welded Plates
Han, Geun-Jo ; Ahn, Sung-Chan ; Shim, Jae-Joon ; Han, Dong-Seop ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 387~392
DOI : 10.3795/KSME-A.2003.27.3.387
The mechanical behavior of two rectangular spot-welded plates under bending is investigated in detail. The equivalent thickness of spot-welded plates is introduced in this study and used in explaining the results. The focus of the analysis is to evaluate the effect of spot-welding from the view point of equivalent thickness. The investigation of deflection has been performed as comparing the result from finite element analysis with the measured data of the spot-welded plates for various parameters, such as aspect ratio, area ratio, and distance ratio of spot-welding points. The effect of spot-welding is as large as 62%(at r
Heat Transfer Analysis and BOG Estimation of Membrane-Type LNG Cargo during Laden Voyage
Heo, Jin-Uk ; Lee, Young-Ju ; Cho, Jin-Rae ; Ha, Mun-Keun ; Lee, Joong-Nam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 393~400
DOI : 10.3795/KSME-A.2003.27.3.393
Excessive generation of BOG during the LNG transportation not only causes the severe financial loss but also leads to the unexpected disaster. Therefore, the carrier cargo insulating interior LNG should be carefully designed based upon an accurate heat transfer analysis. However. it is not simple to analyze heat transfer of LNG cargo, because it is in a complex insulation structure and LNG carrier experiences a complicated heat transfer according to various kinds of voyage conditions. In this paper, we carried out the transient finite element heat transfer analysis for a cargo of Mark-111 membrane-type LNG carrier during laden voyage, and we compared heat transfer rates between considering natural convection and considering conduction. For this goal, we developed a PCL program incorporating with a commercial MSC/NASTRAN FEM code.
A Development of CAD Program for Metal Bellows Diaphragm
Cho, Hae-Yong ; Nam, Gi-Jung ; Oh, Byung-Ki ; Kim, Young-Hun ; Lee, Jae-Hun ; Suh, Jung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 401~408
DOI : 10.3795/KSME-A.2003.27.3.401
A CAD program for metal bellows diaphragm was developed in this study. This program was written in AutoLISP on the AutoCAD system with a personal computer. Basic design concept used in this program is composition of a convolution that is tangent to two lines and 5 circles from given design parameters(initial radius, inner and outer diameter, thickness, pitch, etc.). The effects of altering some design parameters on stress distribution and fatigue life of bellows were estimated using commercial FEM code, NISAII. As a result, the metal bellows diaphragm was successfully designed by the CAD program. It is used to model a bellows geometry in pre-processor of FEM code. The FEM result shows that stress is dependent on straight line length, bellows diameter with same span, and fatigue life is also affected by design parameters.
Development of 2-Dim Lagrangian Hydrocode and Application to Large Deformation Problems
Lee, Min-Hyung ; Kim, Sung-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 409~415
DOI : 10.3795/KSME-A.2003.27.3.409
The purpose of this paper is to develop the 2-Dim Lagrangian Hydrocode for the analysis of large deformations of solids with implementation of the contact algorithm. First, th e governing equations are discretized into a system of algebraic equations. For more accurate and robust contact force computation. the defense node contact algorithm was adopted and implemented. For the verification of the code developed, two cases are carried out; the Taylor-Impact test and two bodies impact. The von -Mises criterion is implemented into the code with the Shock equation of state. The simulation results show a good agreement compared with the published experimental data and results from the commercial code. It is necessary to implement several material models and failure models for applications to different impact and penetration problems.
A Study on Implementation of Risk Based Inspection Procedures to a Petrochemical Plant
Song, Jung-Soo ; Shim, Sang-Hoon ; Kim, Ji-Yoon ; Yoon, Kee-Bong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 416~423
DOI : 10.3795/KSME-A.2003.27.3.416
During the last ten years, the need has been increased for reducing maintenance cost for aged equipments and ensuring safety, efficiency and profitability of petrochemical and refinery plants. RBI (Risk Based Inspection) methodology is one of the most promising technologies satisfying the need in the field of integrity management. In this study, a user-friendly software, realRBl for RBI based on the API 581 code was developed. This software has modules for evaluating qualitative and semi-quantitative risk level, analyzing quantitative risks using the potential consequences of a failure of the pressure boundary, and assessing the likelihood of failure. A quantitative analysis was performed for 16 columns in a domestic NCC (Naphtha Cracking Center) plant whose operating time reaches about 12 years. Each column was considered as two equipment parts by dividing into top and bottom. Generic column failure frequencies were adjusted based on likelihood data. After determining release rate, release duration and release mass for each failure scenario, flammable/explosive and toxic consequences were assessed. Current risks for 32 equipment parts were evaluated and risk based prioritization were determined as a final result.
Vibration Characteristics of a Dummy Fuel Rod Supported by Spacer Grids
Choi, Myoung-Hwan ; Kang, Heung-Seok ; Yoon, Kyung-Ho ; Kim, Hyung-Kyu ; Song, Kee-Nam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 424~431
DOI : 10.3795/KSME-A.2003.27.3.424
The spacer grid is one of the main structural components in the fuel assembly, which supports the fuel rods and maintains coolable geometry from an external load. A vibration test and a finite element analysis using ABAQUS on a dummy fuel rod continuously supported by Optimized H type(OHT) and New Doublet (ND) spacer grids arc performed to obtain the vibration characteristics such as natural frequencies and mode shapes an(1 to verify a finite element model. The results from the test and the finite element analysis are compared by modal assurance criteria (MAC) values. It is resulted that MACs for the first, the third and the fifth mode shapes are relatively good as compared with those of the second an(1 fourth ones. The natural frequency differences between two methods as well as the mode comparison results for the rod with OHT spacer grid are better than those with ND spacer grid. It is judged that the FE model for the ND spacer grid spring should be modified to consider the long contact length which actually happen when the spring supports the rod.
Friction and Wear of Inconel 690 for Steam Generator Tube in Fretting
Lee, Young-Ze ; Lim, Min-Kyu ; Oh, Se-Doo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 432~439
DOI : 10.3795/KSME-A.2003.27.3.432
Inconel 690 for nuclear steam generator tube has more Chromium than the conventionally used Inconel 600 in order to increase the corrosion resistance. To evaluate the tribological characteristics of Inconel 690 under fretting condition the fretting tests were carried out in air and elevated temperature water. Fretting tests of the cross-cylinder type were done under various vibrating amplitudes and applied normal loads in order to measure the friction forces and wear volumes. From the results of fretting wear tests. the wear of Inconel 690 can be predictable using the work rate model. The amounts of friction forces were proportional to relative movement between two fretting surfaces. The friction coefficients were decreased as increasing the normal loads and deceasing the vibrating amplitudes. Depending on fretting environment, distinctively different wear mechanisms and often drastically different wear rates can occur It was found that the fretting wearfactors in air and water at 2
, and 8
, respectively flexibility to model response data with multiple local extreme. In this study, metamodeling techniques are adopted to carry out the shape optimization of a funnel of Cathode Ray Tube, which finds the shape minimizing the local maximum principal stress. Optimum designs using two metamodels are compared and proper metamodel is recommended based on this research.
Residual Strength of Fiber Metal Laminates After Impact
Nam, Hyun-Wook ; Lee, Young-Tae ; Jung, Chang-Kyu ; Han, Kyung-Seop ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 440~449
DOI : 10.3795/KSME-A.2003.27.3.440
Residual strength of fiber metal laminates after impact was studied. 3/4 lay up FML was fabricated using 4 ply prepreg, 2 ply aluminum sheets, and 1 ply steel sheet. Quasi isotropic ([0/45/90/-45]s) and orthotropic ([0/90/0/90]s) FRP were also fabricated to compare with FML. Impact test were conducted by using instrumented drop weight impact machine (Dynatup, Model 8250). Penetration load and absorbed energy of FML were superior to those of FRPs. Tensile tests were conducted to evaluate the residual strength after impact. Strength degradation of FML was less than that of FRP. This means that the damage tolerance of FML is excellent than that of FRP. Residual strength of each specimen was predicted by using Whitney and Nuismer(WN) Model. Impact damage area is assumed as a circular notch in WN model. Damage width is defined as the average of back face and top face damage width of each specimen. Average stress and point stress criterions were used to calculate the characteristic length. It is supposing that a characteristic length is a constant. The distribution of characteristic length shows that the assumption is reasonable. Prediction was well matched with experiment under both stress criterions.
Design of UV-Molding Process to Maximize the Replication Properties in Microstructures
Kim, Dong-Mook ; Kim, Seok-Min ; Sohn, So-Young ; Kang, Shin-Ill ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 450~454
DOI : 10.3795/KSME-A.2003.27.3.450
It is important to control the processing conditions to maximize the replication quality of UV-molded microstructure. In the present study, the tip radius anil surface roughness of V-groove structure were measured to quantify the replication quality. UV-curing dose and the applied pressure were experimentally selected as the governing Processing conditions that affect the replication quality of the UV-molded part. Finally. an experimental optimization technique combining central composite design and desirability function approach was used to maximize the replication quality of UV-molded structure.
Hydrogen Embrittlement of Zr-2.5Nb Pressure Tube at Room Temperature by Precipitated Hydride
Oh, Dong-Joon ; Boo, Myung-Hwan ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 455~463
DOI : 10.3795/KSME-A.2003.27.3.455
The aim of this study is to investigate the hydrogen embrittlement of Zr-2.5Nb CANDU pressure tube at room temperature. The transverse tensile and fracture toughness tests were performed at various hydrogen concentrations using transverse tensile specimens and CCT (curved compact tension) specimens. These specimens were directly machined from the pressure tube retaining original curvatures. Based on the results of these tests. the hydrogen embrittlement phenomenon was clearly observed and fracture toughness parameters of Zr-2.5Nb pressure tube materials such as,
.dJ/da, were dramatically decreased with the increasement of the hydrogen concentration. From microscopic observation by SEM and TEM, it was also revealed that various shapes dimples, fissures and quasi-cleavage were found at the hydrogen-absorbed materials with hydrides while traditional shape dimples were generally located at the as-received materials Through the comparison of the hydride and fissure lengths with the hydrogen concentration the new evaluation method of hydrogen embrittlement was suggested.
Design of Rolling Pass Schedule utilizing Grain Refinement by Strain Accumulation
Park, Jong-Jin ; Lee, Sang-Joo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 464~471
DOI : 10.3795/KSME-A.2003.27.3.464
Among various methods to acquire high strength in plain carbon steel, the mettled of grain refinement by controlling thermo-mechanical processing parameters has gained a great attention if steel rolling industries. In the present study, three different rolling pass schedules are proposed to obtain fine grains which are based on combined results of recrystallization modelling, finite element analysis and experiment. Since meta-dynamic or dynamic recrystallization has been found to be very effective in producing fine grains, reduction ratio and interpass time in the proposed rolling pass schedules were determined in order to invoke such recrystallization as often as possible.
Dynamic Analysis of the Piezo-Actuator for a New Generation Lithography System
Park, Jae-Hak ; Jung, Jong-Chul ; Huh, Kun-Soo ; Chung, Chung-Choo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 3, 2003, Pages 472~477
DOI : 10.3795/KSME-A.2003.27.3.472
A piezo-actuator is an important component for an E-beam lithography system. But it is very difficult to model its characteristics due to nonlinearities such as hysteresis and creep, to the input voltage. In this paper, one-axis micro stage with a piezo-actuator is modeled including the nonlinear properties. Hysteresis and creep are modeled as the first order differential equation and a time-dependent logarithmic function, respectively. The dynamic motion of the stage is also modeled as a mass-spring-damper system and the parameters are determined by utilizing the system identification technique. The simulation tool for a micro stage is constructed using the commercial software and its simulation results are compared with the experimental data.