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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
Editor in Chief :
Volume & Issues
Volume 26, Issue 12 - Dec 2002
Volume 26, Issue 11 - Nov 2002
Volume 26, Issue 10 - Oct 2002
Volume 26, Issue 9 - Sep 2002
Volume 26, Issue 8 - Aug 2002
Volume 26, Issue 7 - Jul 2002
Volume 26, Issue 6 - Jun 2002
Volume 26, Issue 5 - May 2002
Volume 26, Issue 4 - Apr 2002
Volume 26, Issue 3 - Mar 2002
Volume 26, Issue 2 - Feb 2002
Volume 26, Issue 1 - Jan 2002
Selecting the target year
Design, Construction and Use of a Displacement Cage for M(T) Specimens
Kim, Jeong-Yeop ; Song, Ji-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 415~427
DOI : 10.3795/KSME-A.2002.26.3.415
A clip-on type displacement gage was designed and manufactured to use for fatigue crack growth tests of M(T)(Middle-Tension) specimens. The displacement gage has good response for the deformation of the specimen and has been successfully used not only for constant amplitude loading tests but also far variable amplitude loading tests like as single peak overloading and random loading tests. All the materials for the gage can be obtained easily in domestic market, and the manufacturing cost is very low. It is expected that the designing procedure presented in this study can be applied usefully for designing other displacement gages.
Substrate Effects on the Response of PZT Infrared Detectors
Go, Jong-Su ; Gwak, Byeong-Man ; Liu, Weiguo ; Zhu, Weiguang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 428~435
DOI : 10.3795/KSME-A.2002.26.3.428
(PZT30/70) thin film IR detectors has been fabricated and characterised. The PZT30/70 thin film was deposited onto
substrate by the sol-gel process. Four different substrate conditions were studied for their effects on the pyroelectric responses of the IR detectors. The substrate conditions were the combinations of the Si etching and the Pt/Ti patterning. In the Si etched substrate, the
composite layer was used as silicon etch-stop, and was used as the membrane to support the PZT pyroelectric film element as well. The measured pyroelectric current and voltage responses of detectors fabricated on the micro-machined thin
membrane were two orders higher than those of the detectors on the bulk-silicon. For detectors on the membrane substrate, the Pt/Ti patterned detectors showed a 2-times higher pyroelectric response than that of not-patterned detectors. On the other hand, the pyroelectric response of the detectors on the not-etched Si substrate was almost the same, regardless of the Pt/Ti patterning. It was also found that the rise time strongly depended on the substrate thickness: the thicker the substrate was, the longer the rise-time.
Prediction for the Error due to Role Eccentricity in Hole-drilling Method Using Backpropagation Neural Network
Kim, Cheol ; Yang, Won-Ho ; Heo, Seong-Pil ; Jeong, Gi-Hyeon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 436~444
DOI : 10.3795/KSME-A.2002.26.3.436
The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is predicted using the artificial neural network. The neural network has trained training examples of stress ratio, normalized eccentricity, off-centered direction and stress error using backpropagation learning process. The prediction results of the error using the trained neural network are good agreement with FE analyzed ones.
Equivalent Mechanical Property for Stress Analysis on Lined Pipe
Choe, Jae-Seung ; Jeong, Jin-Han ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 445~451
DOI : 10.3795/KSME-A.2002.26.3.445
The refractory-lined pipe is used to protect the system from high-temperature of the internal flow. The property of the refractory has an effect upon the stress analysis for fluid catalytic cracking(FCC) unit piping design. The equivalent elastic modulus and density considering steel and refractory must be applied in the stress analysis of the system. In the research, the theoretical method to obtain the value of the equivalent property is introduced and then the parametric analysis is carried out to understand the characteristic of the material properties, and the stress analysis is performed with reactor, the part of FCC unit.
Feasibility Study of General-purpose Precision Stage Using A Novel Contact-Free Surface Actuator Based on Magnetic Suspension Technology
Jeong, Gwang-Sik ; Lee, Sang-Heon ; Baek, Yun-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 452~460
DOI : 10.3795/KSME-A.2002.26.3.452
The precision stage using a novel contact-free planar actuator based on magnetic farces, magnetized force and Lorentz farce, is suggested. In the promising magnetic structure, the mover is driven directly without any transmission mechanism, and doesn't need any auxiliary driver for its posture calibration. Then it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness, or general-purpose nano-stage. In this paper, we discuss a driving principle of the planar system including the magnetic force generation mechanism, a framework for the force model, governing characteristics of the levitated plate, and a planar motion control of the constructed prototype. And experimental results are given to verify the derived theoretical model and a feasibility of the system.
The Effect of Hot Isostatic Pressing on Mechanical Properties of Cast Aluminum Alloy
Kim, Gi-Tae ; Yang, Hun-Cheol ; Choe, Jae-Yun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 461~470
DOI : 10.3795/KSME-A.2002.26.3.461
The present paper investigates the effect of hot isostatic pressing (HIPing) on mechanical properties, e.g., tensile strength, ductility and impact absorption energy of sand and die casted aluminum alloys. After HIPing at various temperatures and pressure conditions, uniaxial tensile test and Izod impact test of the samples were carried out. The experimental results showed improvements in uniaxial tensile strength, elongation and Izod impact toughness of sand casted aluminum alloy, while deterioration of a tensile strength fur die casted aluminum alloy. The effect of HIPing for microstructure of the cast aluminum alloy was also investigated.
Study on the Prediction of Fatigue Life of Multi-Spot Welded Joints
Ju, Seok-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 471~478
DOI : 10.3795/KSME-A.2002.26.3.471
In real structures, multi-spot welded joints are more frequently used than a single-spot welded joint. Most researches, however, have been focused to a single-spot welded joint until now. In this paper, the fatigue behavior of multi-spot welded joints are investigated using the finite element solutions of the multi-spot welded specimens. The local strain approach is used rather than the stress intensity factor approach to estimate the fatigue life since the former is quite simple and straightforward. It is found that the fatigue behavior of multi-spot welded joints is different from that of single-spot welded joints. The local strain approach is still applicable to multi-spot welded joints.
Test and Analysis of Thermal Ratcheting Deformation for 316L Stainless Steel Cylindrical Structure
Lee, Hyeong-Yeon ; Kim, Jong-Bum ; Lee, Jae-Han ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 479~486
DOI : 10.3795/KSME-A.2002.26.3.479
In this study, the progressive inelastic deformation, so called, thermal ratchet phenomenon which can occur in high temperature structures of liquid metal reactor was simulated with thermal ratchet structural test facility and 316L stainless steel test cylinder. The thermal ratchet deformation at the reactor baffle cylinder of the liquid metal reactor can occur due to the moving temperature distribution along the axial direction as the sodium free surface moves up and down under the cyclic heat-up and cool-down transients. The ratchet deformation was measured with the laser displacement sensor and LVDTs after cooling the structural specimen which is heated up to 55
with steep temperature gradients along the axial direction. The temperature distribution of the test cylinder along the axial direction was measured with 28 channels of thermocouples and was used for the ratchet analysis. The thermal ratchet deformation was analyzed with the constitutive equation of nonlinear combined hardening model which was implemented as ABAQUS user subroutine and the analysis results were compared with those of the test. Thermal ratchet load was applied 9 times and the residual displacement after 9 cycles of thermal load was measured to be 1.79mm. The ratcheting deformation shapes obtained by the analysis with the combined hardening model were in reasonable agreement with those of the structural tests.
Hydrodynamic Behavior Analysis of Vertical-Cylindrical Liquid-Storge Tanks by Mathematically Analytic Method
Park, Jong-Ryul ; O, Taek-Yeol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 487~496
DOI : 10.3795/KSME-A.2002.26.3.487
Hydrodynamic behavior and response of vertical-cylindrical liquid-storage tank is considered. The equation of the liquid motion is shown by Laplace's differential equation with the fluid velocity potential. The solution of the Laplace's differential equation of the liquid motion is expressed with the modified Bessel functions. Only rigid tank is studied. The equivalent masses and heights for the tank contents are presented for engineering design model.
Analysis of Thermal Cycles and Microstructure of Heat Affected Zone for a Low Alloy Carbon Steel Pipe under Multipass Weld
Kim, Tae-Wan ; Ha, Jun-Uk ; Kim, Dong-Jin ; Kim, Jeong-Tae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 497~504
DOI : 10.3795/KSME-A.2002.26.3.497
The purpose of this study is to analyze thermal cycles and to investigate microstructures of heat affected zones for a low alloy carbon steel pipe under a multipass weld. The commercial finite element code SYSWELD is used to compute thermal cycles during multipass weld. The numerical results such as thermal cycles and size of heat affected zone are compared with those of the experiment and the two results show a good agreement. In addition, the microstructure and hardness are investigated from the weldment in detail. The weakest location is founded at intercritical region near the base metal.
Construction of the P-T Limit Curve for the Nuclear Reactor Pressure Vessel Using Influence Coefficient Methods : Cooldown Curve
Jang, Chang-Hui ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 505~513
DOI : 10.3795/KSME-A.2002.26.3.505
During heatup and cooldown of pressurized water reactor, thermal stress was generated in the reactor pressure vessel (RPV) because of the temperature gradient. To prevent potential failure of RPV, pressure was required to be maintained below the P-T limit curves. In this paper, several methods for constructing the P-T limit curves including the ASME Sec. XI, App. G method were explained and the results were compared. Then, the effects of the various parameters such as flaw size, flaw orientation, cooldown rate, existence of chad, and reference fracture toughness, were evaluated. It was found that the current ASME Sec. XI App. G method resulted in the most conservative P-T limit curve. As the more accurate fracture mechanics analysis results were used, some of the conservatism can be removed. Among the parameters analysed, reference flaw orientation and reference fracture toughness curve had the greatest effect on the resulting P-T limit curves.
New Non-linear Modelling for Vibration Analysis of a Straight Pipe Conveying Fluid
Lee, Su-Il ; Jeong, Jin-Tae ; Im, Hyeong-Bin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 514~520
DOI : 10.3795/KSME-A.2002.26.3.514
A new non-linear modelling of a straight pipe conveying fluid is presented for vibration analysis when the pipe is fixed at both ends. Using the Euler-Bernoulli beam theory and the non-linear Lagrange strain theory, from the extended Hamilton's principle are derived the coupled non-linear equations of motion for the longitudinal and transverse displacements. These equations of motion are discretized by using the Galerkin method. After the discretized equations are linearized in the neighbourhood of the equilibrium position, the natural frequencies are computed from the linearized equations. On the other hand, the time histories for the displacements are also obtained by applying the generalized-
time integration method to the non-linear discretized equations. The validity of the new modelling is provided by comparing results from the proposed non-linear equations with those from the equations proposed by Paidoussis.
Development of a New LCF Life Prediction Model of 316L Stainless Steel at Elevated Temperature
Hong, Seong-Gu ; Lee, Soon-Bok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 521~527
DOI : 10.3795/KSME-A.2002.26.3.521
In this paper, tensile behavior and low cycle fatigue behavior of 316L stainless steel which is currently favored structural material for several high temperature components such as the liquid metal cooled fast breeder reactor (LMFBR) were investigated. Research was performed at 55
since working temperature of 316L stainless steel in a real field is from 40
. From tensile tests performed by strain controls with
strain rates at each temperature, negative strain rate response (that is, strain hardening decreases as strain rate increases) and negative temperature response were observed. Strain rate effect was relatively small compared with temperature effect. LCF tests with a constant total strain amplitude were performed by strain control with a high temperature extensometer at R.T, 55
and total strain amplitudes of 0.3%~0.8% were used and test strain rates were
. A new energy based LCF life prediction model which can explain the effects of temperature, strain amplitude and strain rate on fatigue life was proposed and its excellency was verified by comparing with currently used models
Change in Fracture Toughness within Heat-Affected Zone of SA-Welded 9% Ni Steel
Jang, Jae-Il ; Lee, Jeong-Seok ; Lee, Baek-U ; Ju, Jang-Bok ; Gwon, Dong-Il ; Kim, U-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 528~536
DOI : 10.3795/KSME-A.2002.26.3.528
As one step for the safety performance of LNG storage tank, the change in fracture toughness within the X-grooved weld heat-affected zone (HAZ) of newly developed 9% Ni steel, which was submerged arc (SA)-welded, was investigated. Both crack initiation fracture toughness and crack arrest fracture toughness were evaluated by the crack tip opening displacement (CTOD) tests and compact crack arrest (CCA) tests. As the evaluated region approached the fusion line, each test result shorted different tendency, that is, crack initiation toughness decreased while crack arrest toughness increased. The results were discussed through the observation of the microstructural change.
Development of an AFM-Based System for Nano In-Process Measurement of Defects on Machined Surfaces
Gwon, Hyeon-Gyu ; Choe, Seong-Dae ; Park, Mu-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 537~543
DOI : 10.3795/KSME-A.2002.26.3.537
This paper examines a new in-process measurement system for the measurement of micro-defects on the surfaces of brittle materials by using the AFM (Atomic Force Microscopy). A new AFM scanning stage that can also perform nano-scale bending of the sample was developed by adding a bending unit to a commercially available AFM scanner. The bending unit consists of a PZT actuator and sample holder, and can perform static and cyclic three-point bending. The true bending displacement of the bending unit is approximately 1.8mm when 80 volts are applied to the PZT actuator. The frequency response of the bending unit and the stress on the sample were also analyzed, both theoretically and experimentally. Potential surface defects of the sample were successfully detected by this measurement system. It was confirmed that the number of micro-defects on a scratched surface increases when the surface is subjected to a cyclic bending load.
Seismic Design Guidelines for Welded Steel Oil Storge Tank (KS B 6225)
Park, Jong-Ryul ; O, Taek-Yeol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 544~552
DOI : 10.3795/KSME-A.2002.26.3.544
Recommended seismic design guide for the flat bottom vortical-cylindrical oil storage tanks in KS B 6225 is presented. Under earthquake excitations, the hydrodynamic pressure exerted on the tank walls produces overturning moment which may cause either a failure of the anchors or a buckling of the tank shell near its base. The basis for establishing design loads due to hydrodynamic pressure is described including seismic zone risk map in Korea, zone coefficients and the essential facilities factor. This procedure for calculating applied compressive stress on the shell base subjecting to seismic load and for estimating the allowable buckling stress is described.
A Study on Evaluation of Thermal Conductivity for Carbon -Fiber-Reinforced-Plastics
Im, Jae-Gyu ; Song, Jun-Hui ; Choe, Chang-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 553~559
DOI : 10.3795/KSME-A.2002.26.3.553
Carbon-fiber which has very small radial dimension makes us difficult to measure it's properties. So in this paper, we suggest a simple method to measure the thermal conductivity of a carbon-fiber's and carbon-fiber-reinforced-plastics(CFRP) laminates. The thermal conductivity of CFRP laminates was measured experimentally at the same time analytically. The experimental model is based on the one-dimensional analysis of fin sample because CFRP laminates has a thin geometric configuration. The analytical model to measure the thermal conductivity of carbon-fiber is expressed by use of mean-field model which is based on Eshelby's elliptical inclusion problem. Therefore the thermal conductivity of angle-ply laminates can be computed by use of effective longitudinal and transverse thermal conductivities of unidirectional composite of the constituents.
Study on Segmentation of Measured Data with Noise in Reverse Engineeing
Lee, Seok-Hui ; Kim, Ho-Chan ; Heo, Seong-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 560~569
DOI : 10.3795/KSME-A.2002.26.3.560
The segmentation has been performed to the data of good quality in most cases, so the adoption of previous segmentation theory to the measured data with a laser scanner does not produce good result because of the characteristics of the data with noise component. A new approach to perform the segmentation on the scanned data is introduced to deal with problems during reverse engineering process. A triangular net is generated from measured point data, and the segmentation on it is classified as plane, smooth and rough segment. The segmentation result in each segment depends on the user-defined criteria. And the difference of the segmentation between the data of good quality and the data with noise is described and analyzed with several real models. The segment boundaries selected are used to maintain the characteristics of the parts during modeling process, thus they contribute to the automation of the reverse engineering.
A Study on the CFRP Treatment by ion Assisted Reaction Method to Improve T-peel Strength of CFRP/Aluminum Composites
Lee, Gyeong-Yeop ; Yang, Jun-Ho ; Yun, Chang-Seon ; Choe, Nak-Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 570~575
DOI : 10.3795/KSME-A.2002.26.3.570
It is well-known that the bond strength between CFRP(Carbon Fiber Reinforced Plastic) and aluminum is significantly affected by the surface treatment of the CFRP and the aluminum. This study investigates the surface treatment of CFRP to improve the T-peel strength of CFRP/aluminum composites. The surface of
was treated by the ion assisted reaction method under oxygen environment. T-peel strength tests were performed based on the procedure of ASTM D1876-95. The T-peel strength of surface-treated CFRP/aluminum composites was compared with that of untreated CFRP/aluminum composites. The results showed that the T-peel strength of surface-treated CFRP/aluminum composites was about 5.5 times higher than that of untreated CFRP/aluminum composites. SEM examination showed that the improvement of T-peel strength was attributed to the uniform spread and fracture of epoxy adhesive.
Numerical Simulation of High-Velocity Oblique Impact of Mild Steel Spheres Against Mild Steel Plates
Yu, Yo-Han ; Jang, Sun-Nam ; Jeong, Dong-Taek ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 3, 2002, Pages 576~585
DOI : 10.3795/KSME-A.2002.26.3.576
A three-dimensional Lagrangian explicit time-integration finite element code for analyzing the dynamic impact phenomena was developed. It uses four node tetrahedral elements. In order to consider the effects of strain rate hardening, strain hardening and thermal softening, which are frequently observed in high-velocity deformation phenomena, Johnson-Cook model is used as constitutive model. For more accurate and robust contact force computation, the defense node contact algorithm was adopted and implemented. In order to evaluate the performance of the newly developed three-dimensional hydrocode NET3D, numerical simulations of the oblique impact of mild steel plate by mild steel sphere were carried out. Ballistic limit about various oblique angle between 0 degree and 80 degree was estimated through a series of simulations with different initial velocities of sphere. Element eroding by equivalent plastic strain was applied to mild steel spheres and targets. Ballistic limits and fracture characteristics obtained from simulation were compared with experimental results conducted by Finnegan et al. From numerical studies, the following conclusions were reached. (1) Simulations could successfully reproduce the key features observed in experiment such as tensile failure termed "disking"at normal impacts and outwards bending of partially formed plus segments termed "hinge-mode"at oblique impacts. (2) Simulation results fur 60 degrees oblique impact at 0.70 km/s and 0.91 km/s were compared with experimental results and Eulerian hydrocode CTH simulation results. The Lagrangian code NET3D is superior to Eulerian code CTH in the computational accuracy. Agreement with the experimentally obtained final deformed cross-sections of the projectile is excellent. (3) Agreement with the experimental ballistic limit data, particularly at the high-obliquity impacts, is reasonably good. (4) The simulation result is not very sensitive to eroding condition but slightly influenced by friction coefficient.