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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 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
Effect of Tibial Cut Planes and Hinge Axes on Medial Opening Wedge High Tibial Osteotomy
Park, Byoung-Keon ; Lee, Ho-Sang ; Kim, Jay-Jung ; Kim, Cheol-Woong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 835~846
DOI : 10.3795/KSME-A.2011.35.8.835
In medial opening wedge high tibial osteotomy (OWHTO), researchers have reported critical problems caused by unexpected changes in the tibial posterior-slope angle. This unexpected change can be analyzed, but there is no general solution for cases with an oblique hinge axis and cut plane. We propose a general analysis model for OWHTO. We first evaluate the effects according to variation in the hinge axis and tibial cut plane and then define an ideal correction axis. This ideal axis, called the virtual tibial correction axis, is not on the tibial cut plane in general. In this paper, we also present an evaluation of feasibility of the proposed analysis model.
Hybrid Powder-Extrusion Process Involving the Control of Temperature Dwelling Time for Fabricating Spur Gears with Required Properties
Lee, Kyung-Hun ; Hwang, Dae-Won ; Kim, Byung-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 847~853
DOI : 10.3795/KSME-A.2011.35.8.847
In this study, a hybrid powder-extrusion process involving the control of temperature dwelling time for improving the formability of Zn-22Al powder was developed and the effect of dwelling time on the mechanical properties of a spur gear with a pitch circle having a diameter of 1.8 mm was investigated. General extrusion experiments were carried out at different temperatures such as 290, 300, and
. Spur gears with good qualities and without any surface defects were obtained in the case of extrusion temperature of
and ball-milling duration of 32 h. The Vickers hardness distribution was non-uniform, and after the sintering process, an internal crack was generated because of the different deformation energy between gear central part and teeth. To overcome the abovementioned problems, research on controlling the dwelling time of the extrusion temperature in the powder-extrusion process was carried out. Good-quality spur gears were obtained when the dwelling time was 15 min.
Prediction of Three-Dimensional Strip Profile for 6-High Mill in Thin-Strip Rolling
Lee, Sang-Ho ; Song, Gil-Ho ; Lee, Sung-Jin ; Kim, Byung-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 855~861
DOI : 10.3795/KSME-A.2011.35.8.855
We predict the rolled-strip profile for a 6-high mill using thin rolling theory and a numerical model. In the numerical model, we calculate the distributions of the contact pressures between the rolls and the rolling pressure between the strip and the work roll in the transverse direction using the geometric structure of the 6-high mill and the boundary conditions. We determine the distribution of the rolling pressure in the rolling direction via a thin-foil rolling model using Fleck`s theory. We calculate the three-dimensional elastic deformation of the work roll using the pressures of the width and rolling directions. We then obtain the three-dimensional strip profile via the elastic deformation of the work roll during the rolling process. The profile is verified by a thin cold-rolling test and FE simulation.
Experimental Modeling of MR Damper for Cruise Bus
Sohn, Jeong-Hyun ; Jun, Chul-Woong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 863~867
DOI : 10.3795/KSME-A.2011.35.8.863
In this paper, we analyze the characteristic test results of an MR damper for a cruise bus, and we model the nonlinear hysteretic characteristics of the damper using arctangent and polynomial functions. We establish an experimental model of the MR damper according to the input current, and we set the model parameters using the MATLAB Optimization Toolbox. The model is verified via a computer simulation of a full-car model.
A Numerical Study on Dynamic Characteristics of Counter-Rotating Rigid/Deformable Rolls in Press Contact
Lee, Moon-Kyu ; Lee, Sang-Hyuk ; Hur, Nahm-Keon ; Seo, Young-Jin ; Kim, In-Cheol ; Lee, Sung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 869~876
DOI : 10.3795/KSME-A.2011.35.8.869
It is important to analyze the dynamic behavior of counter-rotating rigid/deformable rolls in the roll-coating process, because the stability of the process is affected by the dynamic characteristics. In the present study, the effects of material property, angular velocity, and gap size on the contact pressure and contact shape of the deformable roll are numerically investigated. The behavior of two rolls with a negative gap was analyzed using the finite element method, and the material property of the deformable roll was applied with the Mooney-Rivlin coefficients of the hyper-elastic model. The contact shape is affected by the gap size, and the contact pressure mainly depends on the stiffness of the deformable roll and the gap size. To maintain a negative gap between two rolls, controls such as load and displacement controls must be used. The results indicate that displacement control can reduce the instability.
Mechanical Properties of Stabilizer Link Using Composite Material and Metal
Woo, Young-Man ; Nam, Ki-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 877~882
DOI : 10.3795/KSME-A.2011.35.8.877
Stabilizers are balancing equipment that can reduce the severe rolling of ships, vehicles, and aircraft. We manufactured a stabilizer link using a metal and a composite material with 25% POM-GF. We evaluated the strength of the stabilizer link via tensile, compressive, and ball-stud separation. The standard criteria were satisfied. Of four types of rod, knurled rod has the greatest strength. We improved the shape of the stabilizer-link body by a reanalysis of the injection molding.
Approximate Friction and Gravity Compensation in Haptic Laparoscopic Surgery Simulator
Kim, Sang-Hyun ; Lee, Chang-Gyu ; Kim, Ji-Suk ; Ryu, Je-Ha ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 883~888
DOI : 10.3795/KSME-A.2011.35.8.883
Laparoscopic surgery is being used in various surgical fields because it minimizes scarring. Laparoscopic operations require practical hand skills, so surgeons train on animals and via surgery training tool sets. However, these tool sets do not give the surgeon the sensation of touching real organs. A recently developed laparoscope simulator has a high friction force along the translational axis and a high gravity force along the pitch axis, and therefore it does not permit the operator to control his or her hands delecately. In the paper, the friction force along the axes is auumed to depend on the veolcity, and the gravity force on the angle and distance. We develop a compensation model that combines the gravity and friction force models.
Forming Limit Diagrams of Zircaloy-4 and Zirlo Sheets for Stamping of Spacer Grids of Nuclear Fuel Rods
Seo, Yun-Mi ; Hyun, Hong-Chul ; Lee, Hyung-Yil ; Kim, Nak-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 889~897
DOI : 10.3795/KSME-A.2011.35.8.889
In this work, we investigated the theoretical forming limit models for Zircaloy-4 and Zirlo used for spacer grid of nuclear fuel rods. Tensile and anisotropy tests were performed to obtain stress-strain curves and anisotropic coefficients. The experimental forming limit diagrams (FLD) for two materials were obtained by dome stretching tests following NUMISHEET 96. Theoretical FLD depends on FL models and yield criteria. To obtain the right hand side (RHS) of FLD, we applied the FL models (Swift`s diffuse necking, M-K theory, S-R vertex theory) to Zircaloy-4 and Zirlo sheets. Hill`s local necking theory was adopted for the left hand side (LHS) of FLD. To consider the anisotropy of sheets, the yield criteria of Hill and Hosford were applied. Comparing the predicted curves with the experimental data, we found that the RHS of FLD for Zircaloy-4 can be described by the Swift model (with the Hill`s criterion), while the LHS of the FLD can be explained by Hill model. The FLD for Zirlo can be explained by the S-R model and the Hosford`s criterion (a
A Study of Micro-Channel Fabrication by Micro-Milling and Magnetic Abrasive Deburring
Kwak, Tae-Kyung ; Kwak, Jae-Seob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 899~904
DOI : 10.3795/KSME-A.2011.35.8.899
This This study aims to verify burr formation and to remove the burrs in micro-channel fabrication using micro-machining tools. The machining processes are combined with micro-milling and magnetic abrasive deburring for AISI316 stainless steel. Depending on the micro-milling conditions that are applied, burrs are formed around the side walls. Magnetic abrasive deburring is used to remove these burrs. AISI316 stainless steel is a nonferrous material and its magnetic flux density, which is an important parameter for efficient magnetic abrasive deburring, is low. To enhance this magnetic flux density, we design and build a magnetic array table. The effect of removing burrs is evaluated via SEM and a surface tester.
Study on Improving Stability of 6×6 Skid-Steering Vehicle by Employing Skyhook Control Method
Jeon, Su-Hee ; Lee, Jeong-Han ; Yoo, Wan-Suk ; Kim, Jae-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 905~912
DOI : 10.3795/KSME-A.2011.35.8.905
In order to protect equipment such as controllers, it is important to improve the driving stability of
skidsteering vehicles driven on rough roads. The estimation and improvement of the driving stability should be based on the vertical acceleration, roll acceleration, and pitch acceleration. These variables will be used to achieve multivariable control and increase the vehicle driving stability. In this study, to improve vehicle stability by reducing the vertical acceleration, roll angular acceleration, and pitch angular acceleration, the skyhook control method is employed to control MR(Magnetorheological) dampers equipped with the vehicle. The proposed control system is tested in multibody dynamic simulation.
An Evaluation of Fatigue Life and Strength of Lightweight Bogie Frame Made of Laminate Composites
Jeon, Kwang-Woo ; Shin, Kwang-Bok ; Kim, Jung-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 913~920
DOI : 10.3795/KSME-A.2011.35.8.913
We describe the evaluation of the fatigue life and strength of a lightweight railway bogie frame made of glass fiber/epoxy 4-harness satin-woven composites. To obtain the S-N curve for the evaluation of the fatigue characteristics of the composite bogie frame, we performed a tension-compression fatigue test for composite specimens with different stacking sequences of the warp direction, fill direction, and
direction. We used a stress ratio (R) of -1, a frequency of 5 Hz, and an endurance limit of
. The fatigue strength of the composite bogie frame was evaluated by a Goodman diagram according to JIS E 4207. The results show that the fatigue life and strength of the lightweight composite bogie satisfy the requirements of JIS E 4207. Given its weight, its performance was better than that of a conventional metal bogie frame based on an SM490A steel material.
On B-spline Approximation for Representing Scattered Multivariate Data
Park, Sang-Kun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 921~931
DOI : 10.3795/KSME-A.2011.35.8.921
This paper presents a data-fitting technique in which a B-spline hypervolume is used to approximate a given data set of scattered data samples. We describe the implementation of the data structure of a B-spline hypervolume, and we measure its memory size to show that the representation is compact. The proposed technique includes two algorithms. One is for the determination of the knot vectors of a B-spline hypervolume. The other is for the control points, which are determined by solving a linear least-squares minimization problem where the solution is independent of the data-set complexity. The proposed approach is demonstrated with various data-set configurations to reveal its performance in terms of approximation accuracy, memory use, and running time. In addition, we compare our approach with existing methods and present unconstrained optimization examples to show the potential for various applications.
Investigation of a Novel Rubber-Forming Process Inducing Uniform Surface Pressure for the Fabrication of a Thin Bent Plate with Corrugated Structure
Kim, Min-Hoon ; Park, Sang-Hu ; Jeong, Ho-Seung ; Cho, Jong-Rae ; Ha, Man-Yeung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 933~940
DOI : 10.3795/KSME-A.2011.35.8.933
Thin sheets with a corrugated structure are generally used for the fabrication of heat exchangers for electronics, airplanes, and vehicles. However, it is difficult to fabricate corrugated structures, especially those with a bent angle, using the conventional stamping process because of its intrinsic formation mechanism. We propose a novel rubber-forming process for the effective pressing of the both tilted sides of a plate under the same pressure to form exact corrugated shapes. We use finite element analysis and experiments to study the rubber-forming process parameters, and we evaluate the maximum allowable bent angle for high-quality formation. We show that the proposed method is effective for the fabrication of bent plates with low cost.
A Study on Derailment Safety Analysis in a Conventional Line (Dongdaegoo-Namsunghyun)
Kim, Yong-Won ; Eom, Beom-Gyu ; Kang, Bu-Byoung ; Lee, Hi-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 941~949
DOI : 10.3795/KSME-A.2011.35.8.941
When a railway vehicle passes through curves & transitions, the running speed must be improved by setting limits on the maximum running speed in each section of the conventional line(Dongdaegoo-Namsunghyun) considering derailment safety. Our goal is to improve the maximum running speed of railway vehicle that passes through curves & transitions where there is a high risk of derailment. We examined the influence on the derailment safety when the railway vehicle passes through curves of actual track conditions (Dongdaegoo-Namsunghyun up and down lines). We performed the derailment safety analysis by increasing the running speed on curve radius by 5%.20% compared to existing speed under actual track conditions.
Evaluation of Fretting Fatigue Behavior for Inconel Alloy at 320℃
Kwon, Jae-Do ; Jeung, Han-Kyu ; Chung, Il-Sup ; Park, Dae-Kyu ; Yoon, Dong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 951~956
DOI : 10.3795/KSME-A.2011.35.8.951
Inconel alloys are generally used as steam generator tubes in nuclear power plants. These alloys are highnickel chromium alloys that exhibit excellent resistance to aqueous corrosion. In this paper, the effects of elevated temperatures such as an operating temperature of
on the fretting fatigue behavior of inconel 600 and 690. We observed that the plain and fretting fatigue limits at
were slightly lower than those at room temperature. The frictional forces varied depending on the number of load cycles. After each test, we studied the fretting fatigue mechanisms via SEM observations. These results can be used for structural integrity evaluations at elevated temperatures and for studying fretting damage in steam generator systems.
Finite Element Modeling for the Analysis of In- and Out-of-plane Bulk Elastic Wave Propagation in Piezoelectric Band Gap Structures
Kim, Jae-Eun ; Kim, Yoon-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 957~964
DOI : 10.3795/KSME-A.2011.35.8.957
This investigation presents a finite element method to obtain the transmission properties of bulk elastic waves in piezoelectric band gap structures(phonon crystals) for varying frequencies and modes. To this end, periodic boundary conditions are imposed on a three-dimensional model while both in-plane and out-of-plane modes are included. In particular, the mode decoupling characteristics between in-plane and out-of-plane modes are identified for each electric poling direction and the results are incorporated in the finite element modeling. Through numerical simulations, the proposed modeling method was found to be a useful, effective one for analyzing the wave characteristics of various types of piezoelectric phononic band gap structures.
Diagnostic System for Crashing and Damping Signals in Engine-Assembly Line
Oh, Se-Do ; Kim, Young-Jin ; Seo, Hae-Yun ; Lee, Tae-Hwi ; Lee, Jae-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 965~970
DOI : 10.3795/KSME-A.2011.35.8.965
We develop a diagnostic system to monitor failures in an engine-assembly line. Existing techniques such as sensory analysis, time domain analysis, frequency analysis, and statistical analysis have limitations in the diagnosis of engine-assembly failure when there are abnormal vibration waveforms (crashing and damping signals) during the assembly. We use a wavelet technique to deal with crashing and damping signals. We also implement a new technique for developing diagnostic rules from sensor data, and we demonstrate its validity.
Protector Design and Shock Analysis for a Launch-Reconnaissance Robot
Kang, Bong-Soo ; Park, Moon-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 8, 2011, Pages 971~976
DOI : 10.3795/KSME-A.2011.35.8.971
This paper presents the design concepts of a protector for a launch-reconnaissance robot that is to be deployed for data-collection in hazardous regions. The protector protects the reconnaissance robot inside from shock induced during the process of launch, flight, and landing. Since the outer shells of the protector are automatically opened wide by the unlocking mechanism during the landing stage, the reconnaissance robot can easily exit the protector and move around to carry out its mission. We carefully simulated a finite-element model of the protector with the robot and compared the results with the actual dynamic behavior of the system. Shock- response tests using a droptable showed that the proposed protector filled with silicon material successfully attenuated external shock.