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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 37, Issue 12 - Dec 2013
Volume 37, Issue 11 - Nov 2013
Volume 37, Issue 10 - Oct 2013
Volume 37, Issue 9 - Sep 2013
Volume 37, Issue 8 - Aug 2013
Volume 37, Issue 7 - Jul 2013
Volume 37, Issue 6 - Jun 2013
Volume 37, Issue 5 - May 2013
Volume 37, Issue 4 - Apr 2013
Volume 37, Issue 3 - Mar 2013
Volume 37, Issue 2 - Feb 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Combination of Feature-Based Extraction Process and Manufacturing Resource for Distributed Process Planning
Oh, Ick Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 141~151
DOI : 10.3795/KSME-A.2013.37.2.141
Process planning can be defined as determining detailed methods by which parts can be manufactured from the initial to the finished stage. Process planning starts with determining the manufacturing process based on the geometric shape of the part and the machines and tools required for performing this process. Distributed process planning enables production planning to be performed easily by combining the extracted process and various manufacturing resources such as operations and tools. This study proposes an algorithm to determine the process for a feature-based model and to combine manufacturing resources for the process and implements a distributed process planning system.
Effect of Magnetic Force on Rheological and Compressive Properties of Magneto-Rheological Rubber Composites with Iron Particle and Carbon Nanotubes
Ryu, Sang Ryeoul ; Lee, Dong Joo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 153~160
DOI : 10.3795/KSME-A.2013.37.2.153
An orthotropic magneto-rheological rubber composite (MRRC) based on a general-purpose rubber can be manufactured by using an electromagnetic device during the curing processes of rubber mixtures. The magnetic transmissivity of MRRCs increases with the iron particle (IP) content, and that of aligned MRRCs with a 2-T magnetic field is 1.8 to 2 times higher as compared to that of randomly dispersed MRRCs. The effect of a 2-T magnetic field on carbon nanotube (CNT) reinforced MRRC has been identified clearly, and the magnetic transmissivity is found to be 3.7%. The compressive stress of MRRC (IP 90 + CNT 5, 2 T alignment) under a magnetic field of 0.49 T is 2.1 times higher as compared to that of the matrix. The MR effect of MRRC increases with the IP content, and that of aligned MRRC with the IP 90 and 2 T magnetic field is 20.4%. It is confirmed that the magnetic field when making the specimen and when performing the compression test greatly impacts the compression characteristics.
Development of Hole Expansion Test for Sheet Materials Using Pattern-Recognition Technique
Jang, Seung Hyun ; Kim, Chan Il ; Yang, Seung Han ; Kim, Young Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 161~168
DOI : 10.3795/KSME-A.2013.37.2.161
Nowadays, one of the most interested area of automobile industry is the production of vehicle which has collision safety and ability to produce less amount of
. The achievement of such a dual performance is done by choosing the materials like dual phase steel, ferrite bainite steel, etc. These steels have been used in automotive chassis and body parts, and also used to be formed by hole flanging to meet the goal of strength and design requirement. The formability of sheet material was experimented by hole expansion test and the judgement relies on human eye and his experience. This manual judgement involves many errors and large deviation. This paper develops the automatic crack recognition system which finds a crack based on CCD image to complement the problem of the current method depending on human`s sense.
Classification of Obstacle Shape for Generating Walking Path of Humanoid Robot
Park, Chan-Soo ; Kim, Doik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 169~176
DOI : 10.3795/KSME-A.2013.37.2.169
To generate the walking path of a humanoid robot in an unknown environment, the shapes of obstacles around the robot should be detected accurately. However, doing so incurs a very large computational cost. Therefore this study proposes a method to classify the obstacle shape into three types: a shape small enough for the robot to go over, a shape planar enough for the robot foot to make contact with, and an uncertain shape that must be avoided by the robot. To classify the obstacle shape, first, the range and the number of the obstacles is detected. If an obstacle can make contact with the robot foot, the shape of an obstacle is accurately derived. If an obstacle has uncertain shape or small size, the shape of an obstacle is not detected to minimize the computational load. Experimental results show that the proposed algorithm efficiently classifies the shapes of obstacles around the robot in real time with low computational load.
Study of Influence of Wheel Unloading on Derailment Coefficient of Rolling Stock
Koo, Jeong Seo ; Oh, Hyun Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 177~185
DOI : 10.3795/KSME-A.2013.37.2.177
A new theoretical derailment coefficient model of wheel-climb derailment is proposed to consider the influence of wheel unloading. The derailment coefficient model is based on the theoretical derailment model of a wheelset that was developed to predict the derailment induced by train collisions. Presently, in domestic derailment regulations, a derailment coefficient of 0.8 is allowable using Nadal`s formula, which is for a flange angle of
and a friction coefficient of 0.3. However, theoretical studies focusing on different flange angles to justify the derailment coefficient of 0.8 have not been conducted. Therefore, this study theoretically explains a derailment coefficient of 0.8 using the proposed derailment coefficient model. Furthermore, wheel unloading of up to 50% is accepted without a clear basis. Accordingly, the correlation between a wheel unloading of 50% and a derailment coefficient of 0.8 is confirmed by using the proposed derailment coefficient model. Finally, the validity of the proposed derailment coefficient model is demonstrated through dynamic simulations.
Imperfection Mode of Thin Metallic Sandwich Plate with Pyramidal Metallic Inner Structures
Ahn, Dong-Gyu ; Sun, Hyang-Sun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 187~192
DOI : 10.3795/KSME-A.2013.37.2.187
Thin metallic sandwich plate with pyramidal metallic inner structures is manufactured from a continuous projection welding between face sheets and inner structures. Due to the welding pressure, imperfections of inner structures induced by the deformation of the inner structures occur. The imperfections affect the response of the thin metallic sandwich plate subjected to low-velocity impact loading. The goal of this paper is to obtain a proper dominant imperfection mode of the thin metallic sandwich plate with pyramidal metallic inner structures. The variation of impact responses of the thin metallic sandwich plate for different imperfection modes are investigated by finite element analysis. The results of the FE analysis are compared to those of drop impact experiments. From the results of the comparison, it has been shown that the dominant imperfection mode of the thin metallic sandwich plate with pyramidal metallic inner structures is all type of symmetric imperfection mode with symmetrical imperfections of four struts.
Study of Parts Integration in Product Including Parts having Same Function
Choi, Jun Ho ; Lee, Kun Sang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 193~198
DOI : 10.3795/KSME-A.2013.37.2.193
In general, a product consists of one or more parts. Different parts of a product can perform the same function. According to "the design hypothesis of an integrated part", parts having the same function may be integrated into one part. A part can also perform more than one function. The form or material characteristic of a part may perform its function. In this study, we develop a method for defining the functions of components and for integrating parts having the same functions. We have successfully integrated some parts of a three-hole punch using the proposed method. The results satisfy axiomatic design.
Change of Mechanical Properties of Injection-Molded Glass-Fiber-Reinforced Plastic (GFRP) According to Temperature and Water Absorption for Vehicle Weight Reduction
Chun, Doo-Man ; Ahn, Sung-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 199~204
DOI : 10.3795/KSME-A.2013.37.2.199
Owing to the global energy crisis, studies have strongly focused on realizing energy savings through vehicle weight reduction using light metal alloys or polymer composites. Polymer composites afford many advantages including enabling the fabrication of complex shapes by injection molding, and glass and carbon fibers offer improved mechanical properties. However, the high temperature in an engine room and the high humidity during the rainy season can degrade the mechanical properties of the polymer. In this study, the mechanical properties of injection-molded glass-fiber-reinforced polymer were assessed at a temperature of
and the maximum moisture absorption conditions. The result showed a 23% reduction in the maximum tensile strength under high temperature, 30% reduction under maximum moisture absorption, and 70% reduction under both heat and moisture conditions. For material selection during the design process, the effects of high temperature and high humidity should be considered.
Study of Side Guide to Reduce Top and Tail Camber in Hot Roughing Rolling
Byon, Sang Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 205~212
DOI : 10.3795/KSME-A.2013.37.2.205
This paper presents the results of a numerical study on the effects of a side guide on the top and tail camber. The temperature distribution on the surface of an actual hot-rolled bar was measured using a thermal imager. The measured temperatures were incorporated with finite element analysis, and the thermomechanical behavior of the hot bar was examined. The installation location of the side guide, length of the side guide, and gap between the bar and the insides of the side guide were selected as the parameters to be investigated. The results show that it is more effective to install the side guide at the position where the magnitude of the camber is larger. It is noted that a longer side guide is more effective than a shorter one in reducing the camber. It is also found that the camber decreases in proportion with the guiding gap.
Study of Optimal Machining Conditions of Ultrasonic Machining By Taguchi`s Method
Liu, Jun Wei ; Jin, Jian ; Ko, Tae Jo ; Baek, Dae Kyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 213~218
DOI : 10.3795/KSME-A.2013.37.2.213
Ultrasonic machining (USM) is a new method used in metal cutting. This process does not involve heating or any electrochemical effects, causes low surface damage, has small residual stress, and does not rely on the conductivity of the workpiece. These characteristics are suitable for the machining of brittle materials such as glass or ceramics. However, the use of USM for brittle materials generates cracks on the workpiece. Therefore, in this study, Taguchi`s method was used to optimize the processing conditions of micro holes drilled in glass and ceramics. This method was used to successfully reduce the number of cracks at the entrance and the exit of the micro holes.
Tribological Characteristics of Silver Electroless-Plating Process According to Thicknesses Variation
Lee, Hyun-Dai ; Kim, Dae-Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 219~225
DOI : 10.3795/KSME-A.2013.37.2.219
In this study, the tribological characteristics of silver films that were deposited on a glass substrate by electroless plating were investigated. The electroless-plating method has many notable advantages. It is easy and economical to obtain solid films using this coating process, and it can be applied to both nonconducting and conducting substrates. In this study, silver was selected as the electroless-plating material because it is one of the most common materials used as a solid lubricant. The mechanical properties of silver electroless-plated specimens were investigated for various coating conditions. The thickness of the coating could be controlled by varying the electroless-plating time. The properties of the coatings were investigated using AFM, SEM, and a tribotester.
Study of Prediction of Reliability of Barrel in Small Arms by Dispersion Anlaysis
Kim, Hyun Jun ; Chae, Je Wook ; Choe, Eui Jung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 227~232
DOI : 10.3795/KSME-A.2013.37.2.227
This study proposes a method for predicting the reliability of the barrel in small arms by analyzing the dispersion. The periodicity with which the barrel needs to be changed can be determined by detecting the inner surface directly or by inspecting scratches inside the barrel using an optical sensor. However, soldiers and directors in the logistics command need a more easy way to check the periodicity of barrel. Therefore, this study focuses on the relation between the firing round and the dispersion. A simple equation can be experimentally derived from pre-tests and analyses. This equation is confirmed through firing tests. In this sense, it can be easily applied to determine the periodicity with which the barrel of small arms needs to be changed in the field army.
Evaluation of Fracture Toughness of Copper Thin Films by Combining Numerical Analyses and Experimental Tests
Kim, Hyun-Gyu ; Oh, Se-Young ; Kim, Kwang-Soo ; Lee, Haeng-Soo ; Kim, Seong-Woong ; Kim, Jae-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 233~239
DOI : 10.3795/KSME-A.2013.37.2.233
In this paper, a method of combining numerical analyses and experimental tests is used to evaluate fracture toughness of copper thin films of
thickness. Far-field loadings of a global-local finite element model are inversely estimated by matching crack opening profiles in experiments with numerical results. The fracture toughness is then evaluated using the J-integral for cracks in thin films under far-field loadings. In experiments, Cu thin films attached to Aluminum sheets are loaded indirectly, and crack opening profiles are observed by microscope camera. Stress versus strain curves of Cu thin films are obtained through micro-tensile tests, and the grain size of Cu thin films is observed by TEM analysis. The results show that the fracture toughness of Cu thin films with
sized grains is
Development of Large Propulsion Motor Bearings Considering Slope Conditions
Oh, Seung Tae ; Choi, Jin Woo ; Kang, Byeng Hi ; Kim, Jin ; Choi, Seong Pil ; Bin, Jae Goo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 241~248
DOI : 10.3795/KSME-A.2013.37.2.241
In this study, bearings were developed for a high-power propulsion motor operating in inclined operation conditions through a simulation and similitude-experimental methods using commercial rotating machinery dynamics analysis software. The developed journal bearing is electrically insulated and has low thermal conductivity because each part is connected with 2-4 -mm-thick epoxy plates. To realize an appropriate oil thickness, an oil lift system is adopted, and a half separated structure is applied to ensure the feasibility of maintaining very heavy components. This study discusses some of the key design aspects of sleeve bearing design for high-torque and low-speed propulsion motor applications. Furthermore, the conditions of variable slope tests are examined to prevent oil leakage from the bearing lip seal on the test rig.
Investigation of Mechanism of Frictional Impulse Noise in Closed Cabinet
Lee, Dong Gyu ; Park, Jung-Hyun ; Park, Ki Hong ; Ha, Byung-Kuk ; Kim, Hyeong-Sik ; Park, Sang Hu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 249~255
DOI : 10.3795/KSME-A.2013.37.2.249
A large-sized refrigerator has a complicated inner structure such as a shelf and a rack for product loading. Therefore, when the refrigerator door is opened and closed, the temperature inside the refrigerator varies and vibrations occur due to the physical force applied for opening and closing the door. Owing to these factors, an abnormal sound is generated by the relative distortion between the inner structures. In this study, we aimed to clarify the mechanism that generates this abnormal noise inside the refrigerator using experimental approaches, and we also investigated ways by which to reduce this noise. Toward this end, we developed an experimental setup for measuring the noise, temperature, inner pressure, as well as amount of vibration, and we analyzed the main factors causing the noise based on the experimental results. Furthermore, we suggested a way by which to reduce the noise; this method can be applied in the design stage itself.
Dynamic Analysis of Floating Wave Energy Generation System with Mooring System
Choi, Gyu Seok ; Sohn, Jeong Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 257~263
DOI : 10.3795/KSME-A.2013.37.2.257
In this study, dynamic behaviors of a wave energy generation system (WEGS) that converts wave energy into electric energy are analyzed using multibody dynamics techniques. Many studies have focused on reducing the effects of a mooring system on the motion of a WEGS. Several kinematic constraints and force elements are employed in the modeling stage. Three-dimensional wave load equations are used to implement wave loads. The dynamic behaviors of a WEGS are analyzed under several wave conditions by using MSC/ADAMS, and the rotating speed of the generating shaft is investigated for predicting the electricity capacity. The dynamic behaviors of a WEGS with a mooring system are compared with those of a WEGS without a mooring system. Stability evaluation of a WEGS is carried out through simulation under extreme wave load.
Strength Design of Lightweight Composite Bicycle Frame
Lee, Jin Ah ; Hong, Hyoung Taek ; Chun, Heung Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 265~270
DOI : 10.3795/KSME-A.2013.37.2.265
Strength design for a lightweight bicycle frame made of carbon/epoxy composite laminates was studied using Tsai-Wu`s failure criterion. For the design of bicycle frames, reducing the weight of the frame is of great importance. Furthermore, the frame should satisfy the required strength under specific loading cases. In accordance with the European EN 14764 standard for bicycle frames, three loading cases-pedaling, vertical, and level loadings-were investigated in this study. Because of the anisotropic characteristics of composite materials, it is important to decide the appropriate stacking sequence and the number of layers to be used in the composite bicycle frame. From finite element analysis results, the most suitable stacking sequence of the fiber orientation and the number of layers were determined. The stacking sequences of
Roll Force Prediction of High-Strength Steel Using Foil Rolling Theory in Cold Skin Pass Rolling
Song, Gil Ho ; Jung, Jae Chook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 271~277
DOI : 10.3795/KSME-A.2013.37.2.271
Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high-strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high-strength steel below TS 980 MPa in skin pass rolling.
Evaluation of Composite Mold for Small Composite Propeller
Nhut, Pham Thanh ; Yum, Young Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 2, 2013, Pages 279~285
DOI : 10.3795/KSME-A.2013.37.2.279
The feasibility of substituting a composite mold for an aluminum mold in the fabrication of a small ship propeller was investigated. A small three-blade aluminum propeller was used as a plug for manufacturing the composite mold. A GRPG composite mold and propeller were made from an unsaturated polyester resin, Epovia gelcoat, and woven and mat glass fibers using the compression and vacuum method at room temperature. The hardness and surface roughness and the strength and deformation of the compression and suction molds were experimentally determined. The results were compared with the ISO 484/2 standard and some aluminum alloy materials. The results showed that the deformation of the mold satisfied the tolerance of the thickness of the blade. Some characteristics of the GRPG composite mold were better than those of the aluminum alloy mold (surface smoothness, weight, performance, and cost), and some characteristics were similar (detachment ability and life-cycle). Therefore, the composite mold is considered suitable for the fabrication of a small composite ship propeller.