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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 30, Issue 12 - Dec 2006
Volume 30, Issue 11 - Nov 2006
Volume 30, Issue 10 - Oct 2006
Volume 30, Issue 9 - Sep 2006
Volume 30, Issue 8 - Aug 2006
Volume 30, Issue 7 - Jul 2006
Volume 30, Issue 6 - Jun 2006
Volume 30, Issue 5 - May 2006
Volume 30, Issue 4 - Apr 2006
Volume 30, Issue 3 - Mar 2006
Volume 30, Issue 2 - Feb 2006
Volume 30, Issue 1 - Jan 2006
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Real-time Static Deflection Compensation of an LCD Glass-Handling Robot
Cho Phil-Joo ; Kim Dong-Il ; Kim Hyo-Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 741~749
DOI : 10.3795/KSME-A.2006.30.7.741
For last couple of decades, uses of TFI-LCDs have been expanded to many FPD(Flat Panel Display) applications including mobile displays, desktop monitors and TVs. Furthermore, there has been growing demand for increasingly larger LCD TVs. In order to meet this demand as well as to improve productivity, LCD manufactures have continued to install larger-generation display fabrication facilities which are capable of producing more panels and larger displays per mother glass(substrate). As the size of mother glass becomes larger, a robot required to handle the glass becomes bigger accordingly, and its end effectors(arms) are extended to match the glass size. With this configuration, a considerable static deflection occurs at the end of the robot arms. In order to stack maximum number of mother glasses on a given footprint, the static deflection should be compensated. This paper presents a novel static deflection compensation algorithm. This algorithm requires neither measurement instrument nor additional vertical axis on the robot. It is realized by robot controller software. The forward and inverse kinematics considering compensation always guarantees a unique solution, so the proposed algorithm can be applied to an arbitrary robot position. The algorithm reduced static deflection by 40% in stationary robot state experiment. It also improved vertical path accuracy up to 60% when the arm was running at its maximum speed. This algorithm has been commercialized and successfully applied to a seventh-generation LCD glass-handling robot.
Analysis of Eigenderivative for the Non-Proportional Damped Structure Using the Iterative Method of the Sensitivity Coefficient
Lee Jung-Youn ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 750~756
DOI : 10.3795/KSME-A.2006.30.7.750
This study predicts the modified eigenvectors and eigenvalues of the non-proportional damped structure due to the change in the mass, damping and stiffness of structure by iterative method of the sensitivity coefficient using the original dynamic characteristic. The method is applied to the non-proportional damped 3 degree of freedom system by modifying the mass, damping and stiffness. The predicted dynamic characteristics are showed a good agreement with these from the structural reanalysis using the modified mass, damping and stiffness.
A Description of Thermomechanical Behavior Using a Rheological Model
Lee Keum-Oh ; Hong Seong-Gu ; Lee Soon-Bok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 757~764
DOI : 10.3795/KSME-A.2006.30.7.757
Isothermal cyclic stress-strain deformation and thermomechanical deformation (TMD) of 429EM stainless steel were analyzed using a rheological model employing a bi-linear model. The proposed model was composed of three parameters: elastic modulus, yield stress and tangent modulus. Monotonic stress-strain curves at various temperatures were used to construct the model. The yield stress in the model was nearly same as 0.2% offset yield stress. Hardening relation factor, m, was proposed to relate cyclic hardening to kinematic hardening. Isothermal cyclic stress-strain deformation could be described well by the proposed model. The model was extended to describe TMD. The results revealed that the hi-linear thermomechanical model overestimates the experimental data under both in-phase and out-of-phase conditions in the temperature range of
and it was due to the enhanced dynamic recovery effect.
Effects of Sectional Shape of Die During ECAP Process
Ko Sung-Kwang ; Kim Seong-Yong ; Kwun Sook-In ; Kim Myung-Ho ; Hwang Sun-Keun ; Chae Soo-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 765~772
DOI : 10.3795/KSME-A.2006.30.7.765
Much research efforts have been made on the equal channel angular pressing (ECAP) which produces ultra-fine grains. Along with the experiments, the finite element method has been widely employed to investigate the deformation behavior of specimen during ECAP and the effect of process parameters of ECAP. In this paper, sectional shape change has been investigated during ECAP with the pure-Zr, Zr-702 by using three-dimensional finite element analysis. The results have been compared with experimental results.
Manufacture of High-Aspect-Ratio Polymer Nano-Hair Arrays by UV Nano Embossing Process
Kim Dong-Sung ; Lee Hyun-Sup ; Lee Jung-Hyun ; Lee Kun-Hong ; Kwon Tai-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 773~778
DOI : 10.3795/KSME-A.2006.30.7.773
High-aspect-ratio nano-hair or nano-pillar arrays have great potential in a variety of applications. In this study, we present a simple and cost-effective replication method of high-aspect-ratio polymer nano-hair arrays. Highly ordered nano-porous AAO (anodic aluminum oxide) template was utilized as a reusable nano-mold insert. The AAO nano-mold insert fabricated by the two-step anodization process in this study had close- packed straight nano-pores, which enabled us to replicate densely arranged nano-hairs. The diameter, depth and pore spacing of the nano-pores in the fabricated AAO nano-mold insert were about 200nm,
and 450nm, respectively. For the replication of polymer nano-hair arrays, a UV nano embossing process was applied as a mass production method. The UV nano embossing machine was developed by our group for the purpose of replicating nano-structures by means of non-transparent nano-mold inserts. Densely arranged high-aspect-ratio nano-hair arrays have been successfully manufactured by means of the UV nano embossing process with the AAO nano-mold insert under the optimum processing condition.
Effects of Water Absorption and Surface Treatment on Mechanical Properties of Sisal Textile Reinforced Composites
Kim Hyo-Jin ; Seo Do-Won ; Pak Han-Ju ; Jeon Yang-Bae ; Lim Jae-Kyoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 779~786
DOI : 10.3795/KSME-A.2006.30.7.779
Woven sisal textile reinforced composites were manufactured to evaluate fracture toughness, and tensile test. All specimens were immersed in water five times. All specimens are immersed in pure water during 9 days at room temperature, and dried in 1 day at
. Two kinds of polymer matrices such as epoxy and vinyl-ester were used. Fractured surface were investigated to study the failure mechanism and fiber/matrix interfacial adhesion. It is shows that it can be enhanced to improve their mechanical performance to reveal the relationship between fracture toughness and water absorption fatigue according to different polymer matrices. Water uptake of the epoxy composites was found to increase with cycle times. Mechanical properties are dramatically affected by the water absorption cycles. Water-absorbed samples observed poor mechanical properties such as lower values of maximum strength and extreme elongation. The
values demonstrate a decrease in inclination with increasing cyclic times of wetting and drying fur the epoxy and vinyl-ester.
Influence of Correlation Functions on Maximum Entropy Experimental Design
Lee Tae-Hee ; Kim Seung-Won ; Jung Jae-Jun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 787~793
DOI : 10.3795/KSME-A.2006.30.7.787
Recently kriging model has been widely used in the DACE (Design and Analysis of Computer Experiment) because of prominent predictability of nonlinear response. Since DACE has no random or measurement errors contrast to physical experiment, space filling experimental design that distributes uniformly design points over whole design space should be employed as a sampling method. In this paper, we examine the maximum entropy experimental design that reveals the space filling strategy in which defines the maximum entropy based on Gaussian or exponential. The influence of these two correlation functions on space filling design and their model parameters are investigated. Based on the exploration of numerous numerical tests, enhanced maximum entropy design based on exponential correlation function is suggested.
Effect of Manufacturing Factors on Mechanical Properties of the Rice-husk Powder Composites
Choi J.Y. ; Wang Renliang ; Yoon H.C. ; Lim J.K. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 794~799
DOI : 10.3795/KSME-A.2006.30.7.794
In recent years, the use of natural fiber as reinforcement in polymer composites to replace synthetic fiber such as glass fiber is receiving increasing attention. Because of increasing usage according to the high demand, the cost of thermoplastic has increased rapidly over the past decades. We used a thermoplastic polymer(polypropylene) as the matrix and a lignocellulosic material(rice-husk flour) as the reinforcement filler to prepare a particle-reinforced composite to examine the possibility of using lignocellulosic material as reinforcement filler and to determine data of test results for physical, mechanical and morphological properties of the composite according to the reinforcement filler content in respect to thermoplastic polymer, In this study, PLA/PP rice-husk fiber-reinforced thermoplastic composites that made by the hot press molding method according to appropriate manufacturing process was evaluated as mechanical properties.
New 5-axis Tool Path Generation Algorithm Using CL Surface Transformation
Kim Su-Jin ; Yang Min-Yang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 800~808
DOI : 10.3795/KSME-A.2006.30.7.800
In this paper, the CL surface transformation approach that inversely deforms the 3-axis tool path generated on the deformed CL surface to a 5-axis tool path is introduced. The proposed CL surface transformation approach can be used if the orientation of the cutter is predefined. The CL surface based 3-axis tool path generation algorithms that have been improved well can be applied to the f-axis tool path generation.
Temperature and Loading-Rate Dependence on the Mechanical Behavior of Carbon Nanotubes
Jeong Byeong-Woo ; Lim Jang-Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 809~815
DOI : 10.3795/KSME-A.2006.30.7.809
The temperature and loading-rate dependence on the mechanical behavior of single-walled carbon nanotubes under axial compression and torsion is examined with classical molecular dynamics simulation. The critical buckling is found to depend on the temperature and loading-rate. The yielding under torsion is also found to depend on the temperature and loading-rate. But it is shown that the compression and torsional stiffness are independent of the varied temperatures and loading-rates.
Web-based Interference Verification System for Injection Mold Design
Park Jong-Myoung ; Song In-Ho ; Chung Sung-Chong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 816~825
DOI : 10.3795/KSME-A.2006.30.7.816
This paper describes the development of a web-based interference verification system in the mold design process. Although several commercial CAD systems furnish interference verification functions, those systems are very expensive and inadequate to perform collaborative works over the Internet. In this paper, an efficient and precision hybrid interference verification algorithm for the web-based interference verification system over the distributed environment has been studied. The proposed system uses lightweight CAD files produced from the optimally transformed CAD data through ACIS kernel and InterOp. Collaborators related to the development of a new product are able to verify the interference verification over the Internet without commercial CAD systems. The system reduces production cost, errors and lead-time to the market. Validity of the developed system is confirmed through case studies.
Fatigue Behavior with Respect to Rolling and Residual Stress in Butt-welded Steel Plate
Lee Yong-Bok ; Oh Byung-Duck ; Kim Sung-Yeup ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 826~832
DOI : 10.3795/KSME-A.2006.30.7.826
For the improvement of safety and endurance in welded steel structure, it is needed to consider welding residual stress distribution and rolling directional characteristics of materials. In this study, it was investigated experimentally about characteristics of fatigue crack propagation according to welding residual stress and rolling in FCAW(flux cored arc welding) butt-jointed steel plates. SS400 steel plates of 3mm thickness were selected and tested for this study. When the angles between tensile loading direction and rolling direction in welded materials are increased from
, their fatigue crack propagation rates are increased. These results are same as predicted increments of fatigue crack propagation rate when stress ratio is increased from 0 to 0.5. When the angles of rolling direction and welding direction to tensile loading direction are
respectively, fatigue crack propagation rate in welded material is lowest.
Effect of Thermal Contact Resistance on Transient Thermoelastic Contact for an Elastic Foundation
Jang Yong-Hoon ; Lee Seung-Wook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 833~840
DOI : 10.3795/KSME-A.2006.30.7.833
The paper presents a numerical solution to the problem of a hot rigid indenter sliding over a thermoelastic Winkler foundation with a thermal contact resistance at constant speed. It is shown analytically that no steady-state solution can exist for sufficiently high temperature or sufficiently small normal load or speed, regardless of the thermal contact resistance. However the steady state solution may exist in the same situation if the thermal contact resistance is considered. This means that the effect of the large values of temperature difference and small value of force or velocity which occur at no steady state can be lessened due to the thermal contact resistance. When there is no steady state, the predicted transient behavior involves regions of transient stationary contact interspersed with regions of separation regardless of the thermal contact resistance. Initially, the system typically exhibits a small number of relatively large contact and separation regions, but after the initial transient, the trailing edge of the contact area is only established and the leading edge loses contact, reducing the total extent of contact considerably. As time progresses, larger and larger numbers of small contact areas are established, unlit eventually the accuracy of the algorithm is limited by the discretization used.
Prediction of Protein Tertiary Structure Based on Optimization Design
Jeong Min-Joong ; Lee Joon-Seong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 841~848
DOI : 10.3795/KSME-A.2006.30.7.841
Many researchers are developing computational prediction methods for protein tertiary structures to get much more information of protein. These methods are very attractive on the aspects of breaking technologies of computer hardware and simulation software. One of the computational methods for the prediction is a fragment assembly method which shows good ab initio predictions at several cases. There are many barriers, however, in conventional fragment assembly methods. Argues on protein energy functions and global optimization to predict the structures are in progress fer example. In this study, a new prediction method for protein structures is proposed. The proposed method mainly consists of two parts. The first one is a fragment assembly which uses very shot fragments of representative proteins and produces a prototype of a given sequence query of amino acids. The second one is a global optimization which folds the prototype and makes the only protein structure. The goodness of the proposed method is shown through numerical experiments.
Micro-Deformation of Tows According to Foam Density and Shear Angle During Hemisphere Draping Process
Chung Jee-Gyu ; Chang Seung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 849~856
DOI : 10.3795/KSME-A.2006.30.7.849
In this paper, fabric composite draping on hemisphere moulds were studied to find out the deformation behaviour of micro-tow structures of fabrics during draping and thermoforming. Aluminium and PVC foams were used to fabricate the hemisphere moulds for draping tests. In order to observe the local tow deformation pattern during the draping several specimens for microscopic observation were sectioned from the draped hemisphere structures. The effect of forming condition and mould properties on tow deformation was investigated by the microscopic observation of the tow parameters such as crimp angle. Normalization scheme was performed to compare tow parameter variations with different forming conditions. Stress-strain .elations of two different PVC foams (HT70 and HT110) were tested to investigate the effect of foam property on the micro-tow deformation during forming.
The Effect of Bias and Shear Angles on Compressive Characteristics of Carbon/Epoxy Plain Weave Fabrics
Kim Sung-Jip ; Chang Seung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 857~864
DOI : 10.3795/KSME-A.2006.30.7.857
Various compressive specimens were fabricated using autoclave do-gassing moulding to find out the compressive characteristics of the carbon/epoxy plain weave fabric composites with respect to the bias and shear angles. The stacking angles of the bias specimens are
and those of the sheared specimens are
respectively. In order to verify the effect of micro-tow structures on compressive strength and modulus of the composites, compressive test specimens of uni-directional carbon/epoxy composites with the same materials and the same stacking conditions were fabricated. The modulus and strength of both types of composite specimens were compared with the prediction results based on the CLPT and a proposed strength formula. The tow deformation and fracture modes were investigated by microscopic observation.
Three Dimensional Analysis of High Frequency Induction Welding Phenomena
Kim Hyun-Jung ; Youn Sung-Kie ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 7, 2006, Pages 865~872
DOI : 10.3795/KSME-A.2006.30.7.865
High frequency induction welding is widely employed for longitudinal seam welding of small scale tubes and pipes because of its relatively high processing speed and efficiency. This research is aimed at understanding the variables that affect the quality of the high frequency induction welding. The welding variables include the welding frequency, weld speed, V-angle and tube thickness. Temperature distribution of the tube is calculated through three dimensional coupled electromagnetic and thermal FE analysis. The skin and proximity effects are considered in the electromagnetic analysis. The influence of the impeder is also analyzed. The effects of the operating welding variables on the temperature distribution are investigated quantitatively by exhibiting the heat affected zone (HAZ). The results explain the mechanism of significant enhancement of welding efficiency when the impeder is used. The proper welding conditions without the overheated edge are obtained through FE analysis.