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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
Analytical and Numerical Investigation of Horizontal Force and Stable Position of Work Roll in Backup-Roll-Drive 4-High Cold-Rolling Mill
Byon, Sang-Min ; Lee, Jae-Hyeon ; Park, Heung-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 977~982
DOI : 10.3795/KSME-A.2011.35.9.977
The horizontal force acting on a work roll was examined. This force results from the contact force between the work roll and backup roll in a backup-roll-drive 4-high cold-rolling mill. This horizontal force bends the work roll horizontally and therefore exerts reciprocal action on the roll-gap contour. An analytical model for predicting the horizontal force acting on a work roll, which generates a mean value in the steady state, was presented. The material used for the analysis was high-silicon steel (about 3% Si). A three-dimensional finite element (FE) model was also employed to investigate the non-steady-state behavior of the horizontal force. Results showed that the horizontal force varied with the off-center distance between the work roll and backup roll. In addition, the optimal off-center distance was determined to minimize the horizontal force.
Development of Algorithm for Predicting Fretting Wear
Cho, Yong-Joo ; Kim, Tae-Wan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 983~989
DOI : 10.3795/KSME-A.2011.35.9.983
A numerical algorithm for predicting fretting wear was developed using the boundary element method (BEM). A contact analysis was performed numerically using the relation between the elastic displacement and uniformly distributed loading of a rectangular patch on a semi-infinite solid. Geometrical updating based on nodal wear depths was performed. The wear depths were computed using the Archard's equation for sliding wear. In order to investigate the efficiency of BEM for predicting fretting wear, a problem involving a two-dimensional cylinder on a flat contact was analyzed, comparing it with the simulation model proposed by McColl et al. that was based on the finite element method. The developed method was then applied to the analysis of a spherical contact and it was shown that the developed simulation technique could efficiently predict fretting wear. Moreover, the effect of a step cycle on the solution obtained by the developed method was investigated.
Study on Properties of EPP Bead Foam
Jung, Dong-Won ; Lee, Eung-Kee ; Park, Chul-B. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 991~997
DOI : 10.3795/KSME-A.2011.35.9.991
This paper deals with the basic principles and procedures involved in the steam-chest molding process used for manufacturing expanded polypropylene (EPP) bead foam. Steam-chest molding is an integral process for EPP technology. However, little research has been carried out on the processing conditions for steam-chest molding this process. The characteristics of EPP foam are energy absorption, multiple-impact protection, low weight, structural strength, and durability. In this study, the steam pressure in steam-chest molding was varied to determine the optimum conditions for manufacturing EPP foam. Moreover, annealing was performed after EPP-foam molding to prevent the shrinkage of the steam-molded product. It was possible to verify the mechanism of foam shrinkage by observing the change in weight with time at different annealing temperatures. Moreover, a tensile test and scanning electron microscopy (SEM) analysis were performed to support these experimental results. The dimensional stability of each molded product was investigated at different steam pressures.
Effects of Strain-Induced Crystallization on Mechanical Properties of Elastomeric Composites Containing Carbon Nanotubes and Carbon Black
Sung, Jong-Hwan ; Ryu, Sang-Ryeoul ; Lee, Dong-Joo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 999~1005
DOI : 10.3795/KSME-A.2011.35.9.999
The effects of strain-induced crystallization (SIC) on the mechanical properties of elastomeric composites as functions of extension ratio (
), multiwalled carbon nanotube (CNT) content, and carbon black (CB) content are investigated. The differential scanning calorimetry (DSC) analysis shows that the degree of crystallinity increases with the increase in the CB and CNT content. As
increases, the glass transition temperature (Tg) of the composites increases, and the latent heat of crystallization (LHc) of the composites is maximum at
=1.5. It is found that the mechanical properties have a linear relation with LHc, depending on the CNT content. According to the TGA (thermogravimetric analysis), the weight loss of the composite matrix is 94.3% and the weight of the composites decreases with the filler content. The ratio of tensile modulus (
) is higher than that of tensile strength (
) because of the CNT orientation inside the elastomeric composites.
Shape Optimization of Multilayer Bellows by Using Sequential Experimental Design
Oh, Sang-Kyun ; Lee, Kwang-Ki ; Suh, Chang-Hee ; Jung, Yun-Chul ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1007~1013
DOI : 10.3795/KSME-A.2011.35.9.1007
Because of their high flexibility and durability, multilayer bellows are manufactured for use in commercial vehicles, while single-layer bellows are manufactured for use in passenger vehicles. A study based on the finite element method (FEM) and shape optimization for the single-layer bellows has been actively performed; however, until now, a study based on the FEM has rarely been performed for the multilayer bellows with gaps between the layers. This paper presents a finite-element modeling scheme for the multilayer bellows to improve simulation reliability during the evaluation of stress and flexibility. For performing shape optimization for the multilayer bellows, DOE (design of experiment) and the Kriging metamodel followed by the D-optimal method are used.
Study on Basic Characteristics of Hollow Piezoelectric Actuator for Driving Nanoscale Stamp
Park, Jung-Ho ; Lee, Hu-Seung ; Lee, Jae-Jong ; Yun, So-Nam ; Ham, Young-Bog ; Jang, Sung-Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1015~1020
DOI : 10.3795/KSME-A.2011.35.9.1015
Nanoimprint lithography has been actively investigated. This method can replicate a nanopatterned master stamp onto a thin polymer film on a silicon substrate and so on. In this study, a square-shaped hollow piezoelectric actuator is presented, which is newly developed. This actuator is used for driving a nanoscale stamp in nanoimprint lithography instead of a conventional electric motor. The fabricated prototype actuator has 95 layers and side lengths of 23 mm and 18 mm for the outer and inner squares, respectively. By adopting a novel process instead of the conventional forming process for fabricating a one-layer actuator, the one-layer is composed of four rectangular segments produced by sawing a ceramic film with a thickness of 0.3 mm. The basic characteristics on displacement and generation force of the fabricated prototype actuator are experimentally investigated. Furthermore, the displacement characteristics obtained by using a PI controller are tested and discussed.
Influence Factor Analysis of Projectile on the Fracture Behavior of Aluminum Alloys Under High Velocity Impact with Latin Square Method
Kim, Jong-Tak ; Cho, Chang-Hee ; Kim, Jin-Young ; Kim, Tae-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1021~1026
DOI : 10.3795/KSME-A.2011.35.9.1021
Structural impact problems are becoming increasingly important for a modern defense industry, high-speed transportation, and other applications because of the weight reduction with high strength. In this study, a numerical investigation on the impact fracture behavior of aluminum plates was performed under various projectile conditions such as nose shapes, velocities, and incidence angles. In order to reduce the iterative numerical analysis, the Latin Square Method was employed. The influence factor was then determined by an FE analysis according to the conditions. The results were evaluated by means of a statistical significance interpretation using variance assessment. It was shown that the velocity and incidence angle can be the most important influence factors representing the impact absorption energy and plastic deformation, respectively.
Methods for Suppressing Tearing of PET Coating During Forming of VCM Steel Sheet for Fabricating Washer
Son, Young-Ki ; Lee, Chan-Joo ; Byeon, Sang-Doek ; Kim, Myong-Dok ; Kim, Byung-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1027~1033
DOI : 10.3795/KSME-A.2011.35.9.1027
A VCM sheet is a metal sheet on which PET/PVC is coated for outer panels of home appliances. The purpose of this study is to obtain methods for suppressing PET tearing that occurs during the press forming of the VCM sheet. In order to identity the factors that minimize PET tearing, an FE analysis was performed. The occurrence of PET tearing cannot be predicted using the conventional forming limit diagram. PET is torn by friction between a die and sheet, which is caused by the thickening of material at a die corner. To reduce the thickening of material, the blank shape was re-designed and the thickened material at a flange was removed by a trimming process. The results of the FE-analysis involving modified process parameters showed that the thickness of the product at a die corner is distributed within the clearance of drawing and flangeforming process. A forming experiment was conducted to verify the proposed process parameters. A good final product was obtained without PET tearing of the VCM sheet.
Study on Metal Microfilter Coated with Ceramics by Using Plasma Thermal Spray Method
Song, In-Gyu ; Lee, Young-Min ; Shin, Hyun-Myung ; Choi, Hae-Woon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1035~1040
DOI : 10.3795/KSME-A.2011.35.9.1035
This research was performed on a microfilter made of a hybrid material (ceramic + metal) that was coated with ceramics on the metal-filter surface by using the thermal spray method. The ceramic powders used were
powder with a particle size of
(98%+)powder with a particle size of
. The metal filters were filter-grade
sintered metal powder filters (SIKA-R 20 IS, 30 IS, 50 IS; Sinter Metals Filters) and filter-grade
sintered mesh filter with five layers. Ceramic-coated filters that were coated using the thermal spray method had a great influence on powder material, particle size, and coating thickness. However, these filters showed a fine performance when used as micro-filters.
Modeling and Analysis of Size-Dependent Structural Problems by Using Low-Order Finite Elements with Strain Gradient Plasticity
Park, Moon-Shik ; Suh, Yeong-Sung ; Song, Seung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1041~1050
DOI : 10.3795/KSME-A.2011.35.9.1041
An elasto-plastic finite element method using the theory of strain gradient plasticity is proposed to evaluate the size dependency of structural plasticity that occurs when the configuration size decreases to micron scale. For this method, we suggest a low-order plane and three-dimensional displacement-based elements, eliminating the need for a high order, many degrees of freedom, a mixed element, or super elements, which have been considered necessary in previous researches. The proposed method can be performed in the framework of nonlinear incremental analysis in which plastic strains are calculated and averaged at nodes. These strains are then interpolated and differentiated for gradient calculation. We adopted a strain-gradient-hardening constitutive equation from the Taylor dislocation model, which requires the plastic strain gradient. The developed finite elements are tested numerically on the basis of typical size-effect problems such as micro-bending, micro-torsion, and micro-voids. With respect to the strain gradient plasticity, i.e., the size effects, the results obtained by using the proposed method, which are simple in their calculation, are in good agreement with the experimental results cited in previously published papers.
Influence of Density Variation on Stress and Displacement Fields at a Propagating Mode-III Crack Tip in Orthotropic Functionally Graded Materials
Lee, Kwang-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1051~1061
DOI : 10.3795/KSME-A.2011.35.9.1051
The influences of density variation on stress and displacement fields at a propagating Mode-III crack tip in orthotropic functionally graded materials (OFGMs) are studied. The crack propagates dynamically at a right angle to the gradient of physical properties. Three kinds of elasticity and density gradients are analyzed in this study. They are as follows: (1) the density varies without elasticity variation, (2) the directions of the density and elasticity gradients are opposite to each other, and (3) same. For these cases, the stress and displacement fields at the crack tip are developed and the dynamic stress intensity factors for propagating cracks are also studied. When the crack speed is low, the influence of density variation on the stresses and displacement is low. However, when the crack speed is high, this influence is very high.
Application of Data Acquisition System for MES
Lee, Seung-Woo ; Lee, Jai-Kyung ; Nam, So-Jung ; Park, Jong-Kweon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1063~1070
DOI : 10.3795/KSME-A.2011.35.9.1063
The manufacturing execution system (MES) for product production handles different production processes according to the product characteristics and different types of data according to the process being considered. For efficiently providing the data pertaining to production equipment to production systems such as the MES, data collection through the equipment interface is required for obtaining the production data pertaining to field equipment. In this paper, a method is proposed for collecting the production data through the equipment interface in order to collect the various types of production-equipment data from the field. The proposed method is applied to a real manufacturing system to verify its efficiency. A more powerful MES can be constructed with a data acquisition system that acquires the status data at the shop-floor level.
Study on Three-Dimensional Curved-Surface Machining Using Industrial Articulated Robot
Jung, Chang-Wook ; Noh, Tae-Yang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1071~1076
DOI : 10.3795/KSME-A.2011.35.9.1071
NC machines are generally used for machining operations because of their position accuracy, path accuracy, and machining reaction force. However, some NC machines require a very large space and are expensive. Recently, industrial articulated robot arms with large handling capability and wrist torque have been developed and the corresponding sensor technology has been improved. A machining robot for three-dimensional large curved objects was developed on the basis of an automatic-path-generation method. A self-position-compensation method with a laser displacement sensor was adopted for the six-axis robot developed, because the large articulated robot arms had poor position accuracy. An automatic-path-generation method using specific points was adopted to reduce the number of teaching points and time. In order to determine the proper machining conditions, various machining conditions such as tool rotation speed, cutting angle, cutting depth, and tool moving speed, were evaluated.
Caulking and Gap Analysis for a Ball Joint
Hwang, Seok-Cheol ; Kim, Jong-Kyu ; Seo, Sun-Min ; Han, Seung-Ho ; Lee, Kwon-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1077~1082
DOI : 10.3795/KSME-A.2011.35.9.1077
Ball joint is a rotating and swiveling element that is typically the interface between two parts. In an automobile, the ball joint is the component that connects the control arms to the steering knuckles by playing a role of bearing. The ball joint can also be installed in linkage systems for motion control applications. This paper describes the simulation strategy for a ball joint analysis, considering manufacturing process. Its manufacturing process can be divided into plugging and spinning. Then, the interested response is selected as the stress distribution generated between its ball and bearing. In this paper, a commercial code of NX DAFUL 2.0 using an implicit integration method is introduced to calculate the response. In addition, the gap analysis is performed to investigate the fitness. Also, the optimum design is suggested through case studies.
Concept Development and Review of Current Technical Issues for SFR Steam Generator
Nam, Ho-Yun ; Kim, Jong-Bum ; Lee, Jae-Han ; Park, Chang-Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1083~1090
DOI : 10.3795/KSME-A.2011.35.9.1083
A steam generator poses many difficulties during the development of a sodium-cooled fast reactor because of the sodium-water-reaction problems. Until now, several types of steam generators have been developed, but the specifications of these generators differed in each country. Moreover, even if a country had developed a steam generator, it was not used in the subsequent reactor because the current techniques were not stabilized to select the proper steam generator. As a common development, the Benson steam cycle with few welding locations and high economical efficiency may be adopted. Moreover, the design is dwelled on the convenience of inspection, detection, control, and maintenance for the wear caused by sodiumwater reactions. The specifications of the designed steam generators were reviewed and the current technical problems for steam generators were analyzed. Concepts were proposed to overcome the current technical problems for steam generators.
Modeling and Analysis of Arbitrarily Shaped Three-Dimensional Cracks
Park, Jai-Hak ; Nikishkov, G.P. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1091~1097
DOI : 10.3795/KSME-A.2011.35.9.1091
The SGBEM-FEM alternating method has been known to be a very effective method for analyzing threedimensional cracks in a finite body. The accurate values of the stress intensity factor can be obtained for a general planar or nonplanar three-dimensional crack. In the existing method, eight-noded quadrilateral boundary elements are used to model a crack. In some cases, three-node triangle boundary elements are more convenient for the modeling of a crack with a general shape. In this study, a crack is modeled with three-noded triangular and seven-noded quadrilateral elements by using the advancing-front mesh generation method. The stress intensity factors are obtained for cracks with several shapes and the accuracy of results is examined.
Effect of Strut Waviness on Structural Performance of Wire-Woven Bulk Kagome Cores
Lee, Ki-Won ; Kang, Ki-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1099~1103
DOI : 10.3795/KSME-A.2011.35.9.1099
Since the mechanical strength and stiffness of wire-woven bulk Kagome (BK) have been theoretically estimated by assuming that WBK is composed of straight struts, the analytical solutions occasionally give substantial errors as compared with the experimental results. The struts of WBK are helically formed, which results in errors in the estimations In this study, for accurately predicting the mechanical properties of WBK, the effects of waviness and brazed part are taken into account for estimating the strength and stiffness of WBK. The results are compared with the measured experimental results and the results estimated by a finite element analysis performed on a unit cell under periodic boundary conditions (PBC).
Influence of Surface Roughness on Morphology of Aluminum Alloy After Pulsed-Laser Irradiation
Choi, Sung-Ho ; Kim, Chung-Seok ; Jhang, Kyung-Young ; Shin, Wan-Soon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1105~1111
DOI : 10.3795/KSME-A.2011.35.9.1105
The objective of this study is to investigate the influence of surface roughness on the morphology of aluminum 6061-T6 alloy after irradiation with a Nd:YAG pulsed laser. The test specimen was prepared by a polishing process using a diamond paste (
) and emery polishing papers (#100, #220, #600, #2400) to obtain different initial surface roughness. After irradiation with ten pulsed-laser shots, the surface morphology was examined by using scanning electron microscopy (SEM), optical microscopy (OM), and atomic force microscopy (AFM). The diameter of the melted zone increased with the surface roughness because the multiple reflections and absorption of the laser beam occurred on the surface because of the surface roughness, so that the absorptance of the laser beam changed. This result was verified using the relative absorptance calculated from the diameter of the melted zone with the surface roughness and the diameter increased with the average surface roughness.
Reflection and Transmission Characteristics of Oblique-Incidence Ultrasonic Waves at Solid-Solid Contact Interfaces
Nam, Tae-Hyung ; Kim, Chung-Seok ; Lee, Tae-Hun ; Jhang, Kyung-Young ; Kim, Noh-Yu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1113~1118
DOI : 10.3795/KSME-A.2011.35.9.1113
In order to evaluate the characteristics of solid-solid contact interfaces, reflection or transmission techniques involving normal-incidence longitudinal waves are generally used. However, these normal-incidence techniques are of limited use in field applications such as in the inspection of welded parts. The oblique-incidence ultrasonic technique may be an alternative for overcoming these problems. However, in this technique, the mode conversion at the contact interfaces should be taken into account along with the normal and tangential interface stiffness. In this study, we have suggested a theoretical model for obliqueincidence ultrasonic waves at the contact interfaces and analyzed their reflection and transmission characteristics. Experimental results showed that the measured reflection coefficient and second harmonic wave agreed well with the suggested theoretical model. Consequently, the oblique-incidence technique can be a promising method for evaluating the characteristics of the contact interfaces.
High Cyclic Fatigue Life and Fracture Behaviors of Shot-Peened Bearing Steel
Yoon, Sang-Jae ; Choi, Nak-Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1119~1129
DOI : 10.3795/KSME-A.2011.35.9.1119
Shot-peening effects on the fatigue behavior of bearing steel were investigated under the high cyclic loading. Hourglass shape specimens were made of bearing steel(JIS-SUJ2) for rotary bending fatigue tests. Two kinds of treatments were performed : a heat treatment and a shot-peened surface treatment after the heat treatment. The fracture surfaces of specimens were classified into two types of fracture mode : the surface fracture mode induced by a surface defect and the internal fracture mode induced by a nonmetallic inclusion. Inclusion depth and shape affected considerably the fatigue life. Shot-peening treatment improved much the fatigue life of the bearing steel under low and high levels of cyclic loads. Probabilistic-stress-life (P-S-N) curves were suggested for the reliable fatigue life estimation of the improved bearing steel.
Study of Acoustic Emission Parameters Involved in Burst Test for CNG-Vehicle Fuel Tank
Jee, Hyun-Sup ; Lee, Jong-O ; Ju, No-Hoe ; Lee, Jong-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1131~1136
DOI : 10.3795/KSME-A.2011.35.9.1131
This study is performed on the acoustic emission parameters involved in a burst test for a CNG-vehicle fuel tank. A resonant AE sensor with a central frequency of 150 kHz was attached on the composite materials in the center of the fuel tank. The analysis of AE parameters such as hit, amplitude, count, duration, risetime, and signal strength during load holding was performed. The total count and total signal strength are effective tools for the damage evaluation of a CNG fuel tank.
Macroscopic High-Temperature Structural Analysis Model of Small-Scale PCHE Prototype (II)
Song, Kee-Nam ; Lee, Heong-Yeon ; Hong, Sung-Deok ; Park, Hong-Yoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 9, 2011, Pages 1137~1143
DOI : 10.3795/KSME-A.2011.35.9.1137
The IHX (intermediate heat exchanger) of a VHTR (very high-temperature reactor) is a core component that transfers the high heat generated by the VHTR at
to a hydrogen production plant. Korea Atomic Energy Research Institute manufactured a small-scale prototype of a PCHE (printed circuit heat exchanger) that was being considered as a candidate for the IHX. In this study, as a part of high-temperature structural integrity evaluation of the small-scale PCHE prototype, we carried out high-temperature structural analysis modeling and macroscopic thermal and elastic structural analysis for the small-scale PCHE prototype under small-scale gas-loop test conditions. The modeling and analysis were performed as a precedent study prior to the performance test in the small-scale gas loop. The results obtained in this study will be compared with the test results for the small-scale PCHE. Moreover, these results will be used in the design of a medium-scale PCHE prototype.