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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 21, Issue 12 - Dec 1997
Volume 21, Issue 11 - Nov 1997
Volume 21, Issue 10 - Oct 1997
Volume 21, Issue 9 - Sep 1997
Volume 21, Issue 8 - Aug 1997
Volume 21, Issue 7 - Jul 1997
Volume 21, Issue 6 - Jun 1997
Volume 21, Issue 4 - Apr 1997
Volume 21, Issue 5 - Jan 1997
Volume 21, Issue 3 - Jan 1997
Volume 21, Issue 2 - Jan 1997
Volume 21, Issue 1 - Jan 1997
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Analysis of stress and stress intensity factor in bonded dissimilar materials by boundary element method
Yi, W ; Chung, N.Y ; Yu, Y.C ; Jeong, E.S ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1357~1363
DOI : 10.22634/KSME-A.19220.127.116.117
Currently it is increasing to use th bonded dissimilar materials in the various field of advanced engineering such as the highly rigid and lighter vehicle, plastic molding LSI package and metal/ceramic bonded joint. In spite of such a wide application of the bonded dissimilar materials, the evaluation method of the bonding strength has not been established yet. Therefore in this paper we analyze the interface crack problem by introducing fracture mechanics parameters as the basic research about estimating of the strength of adhesive joints. The variation of stress intensity factor according to the elastic modulus of adherend and thickness of bonded layer are investigated. Numerical results are based on the results of boundary element analysis of four different type butt joints subjected to uniaxial tension loading.
An upper-bound analysis for the guiding type forging of helical gears
Choi, Jae-Chan ; Choi, Yeong ; Tak, Seong-Jun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1364~1372
DOI : 10.22634/KSME-A.1918.104.22.1684
In this paper, the forging of helical gears has been investigated. Punch is tooth-shaped as is the die insert. The punch compresses a cylindrical billet placed in a die insert. As a consequence the material of billet flows into the tooth region. The forging has been analysed by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, an involute curve has been introduced to represent tooth profile of the gear. Numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth, helix angle and friction factor on the forging of helical gears. Some forging experimentswere carried out with aluminum alloy to show the validity of the analysis. Good agreement was found between the predicted values of the forging load and obtained from the experimental results.
development of design support system for gear drives
Chong, Tae-Hyong ; Bae, In-Ho ; Kim, Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1373~1384
DOI : 10.22634/KSME-A.1922.214.171.1243
There have been a number of expert systems which are concerned with the design of machine elements such as gear, shaft, bearing and so on. However the design of more complicated systems such as gear dreives are still difficult. Thus, in consideration of the integrative nature of the system, we develop a design support system for gear drives which is composed of various machine elements-gear, shaft, bearing, key and so on. Design systems for each machine element are developed and integrated through object-oriented approach. Databases essential for data reference and/or data control in the design process are built up independently and interface to the main program. Expert systems are also developed and integrated for intelligent support to the designer, in those of the determination of gear specification and the selection of bearing types. Through the integration of design environment for each machine element, it is expected to increase the convenience in the design process and the stability of the design solution. And also the system management, including addition of various design/analysis modules and expansion to the gear drives of other types, can be conveniently achieved since the system has developed under due consideration of its efficiency and expandability through object-oriented programming approach.
Stability of beck's column with a rotatory spring restraining its free end
Yun, Han-Ik ; Im, Sun-Hong ; Yu, Jin-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1385~1391
DOI : 10.22634/KSME-A.19126.96.36.1995
An analysis is presented on the stability of an elastic cantilever column subjected to a concentrated follower force as to the influence of the elastic restraint and a tip mass at the free end. The elastic restraint is formed by the rotatory springs. For this purpose, the governing equations and boundary conditions are derived by using Hamilton's principle, and the critical flutter loads and frequencies are obtained from the numerical evaluation of the eigenvalue functions of the considered system.
Determination of stress intensity factor by means of ACPD technique for ferromagnetic materials
Lee, Jeong-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1392~1399
DOI : 10.22634/KSME-A.19188.8.131.522
In order to determine the Mode I stress intensity factor (
) experimentally by means of the alternating current potential drop(ACPD) technique, the change in potential drop due to load for a ferromagnetic material containing a two-dimensional surface crack was examined. The cause of the change in potential drop and the effect of the magnetic flux on the change in potential drop were clarified by using the measuring systems with and without removing the magnetic flux from the circumference of the specimen. To remove the magnetic flux, a new measuring system was made by utilizing the characteristic of coaxial transmission line. The change in potential drop in the case without magnetic flux in the air was caused by the change in electromagnetic properties near the crack tip due to magnetization. The relationship between the change in potential drop and the change in
was linealized by demagnetization and was found to be independent of the crack length.
The effect of forging process conditions of semi-solid aluminum material on mechanical properties
Gang, Chung-Gil ; Gang, Dong-U ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1400~1413
DOI : 10.22634/KSME-A.19184.108.40.2060
Semi-solid forging(SSF) process of A356 aluminium alloy has been studied to assess the effect of process variables on the component integrity. Semi-solid material(SSM) was fabricated by mechanical and electro-magnetic stirring process. The fabricated SSM by using mechanical stirring process has been carried out on cooling rate of 0.022.deg. C/sec 0.0094.deg. C/sec and stirring speed n=600, 1000 rpm, respectively. The fabricated SSM by using electro-magnetic stirring process is supplied by Pechiney. The holding time and temperature in the semi-solid state before forging also affects the globular microstructure of alloy. Therefore, the influence of these two parameters is discussed in terms of the microstructure of alloy. The SSF process has been conducted with three different die temperatures(
=250.deg. C, 300.deg. C, 350.deg. C) and two kinds of gate types(straight gate and orifice gate). This paper is to investigate the influence of gate shapes of die on filling phenomena in SSF process more deeply. The mechanical properties of forged components were also investigated for variation of process conditions such as die temperature, gate shape and SSM.
Bond Gragh Prototypes: A General Model for Dynamic Systems in Terms of Bond Graphs
Park, Jeon-Soo ; Kim, Jong-Shik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1414~1421
DOI : 10.22634/KSME-A.19220.127.116.114
This paper examines the physics and mechanics governing the dynamic interaction between physical systems and suggests the four structures of bond graph prototypes, considered as a general model that can promise their dynamic behavior physically resonable. The bond graph prototypes originating from the paper are more realistic junction structures than those used to model dynamic systems conventionally by bond graph standards in whether physical constraints are involved or not when the energy exchange between two dynamic components arises. It is shown that the bond graph prototypes are dynamic or energetic in their describing equations compared to the bond graph standards, and connectivity and causality are properties of dynamic systems upon which the steps developed in this paper for the bond graph prototypes are wholly based and their definitions an concepts are highly emphasized all through the paper.
Evaluation of corrosion resistance by electrochemical method for Ni-Cr-Mo-V steel
Kwon, Jae-Do ; Moon, Yun-Bae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1422~1431
DOI : 10.22634/KSME-A.1918.104.22.1682
When the structures are exposed to their own an application for a long period, a number of variables such as strength properties and corrosion resistance, so on are expected to change. In the present investigation the corrosion behavior and resistance for the original and degraded materials of Ni-Cr-Mo-V steel were evaluated under the conditions of pH 3, 6, 9 and 12 in a distilled water environment. The electrochemical polarization technique was employed in this investigation. Based upon the experimental results obtained, the following conclusions were drawn. A severe and uniform corrosion was observed for both original and degraded materials under the condition of pH 3. At pH 6 and pH 9, these materials showed the degradation by a pitting corrosion. The materials under pH 12 environment were degraded by a uniform corrosion. The corrosion rate per year were the highest in the pH 3 environment, followed by pH 12, pH 6 and pH 9 environment in order. The corrosion resistance was decreased from the original material, slow cooled material (10.deg. C/hr) and step cooled material in order.
유연성과 강성을 고려한 최적구조설계
Min, Seungjae ; Nishiwaki, Shinji ; Kikuchi, Noboru ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1432~1440
DOI : 10.22634/KSME-A.1922.214.171.1242
The flexibility as well as the stiffness is required to perform mechanical function of a structure such as compliant mechanisms, which can be applied to MEMS(Micro-Electro-Mechanical Systems), flexible manufacturing devices, and design for no assembly. In this paper, the optimal design problem to achieve both structural flexibility and stiffness is formulated using multi-objective function, and the optimization problem is resolved by using Finite Element Method(FEM) and Sequential Linear Programming(SLP). Design examples of compliant mechanisms are presented to validate the design method.
An analytical study on unsteady thermal stresses of functionally graded materials
Choi, Deok-Kee ; Kim, Chang-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1441~1451
DOI : 10.22634/KSME-A.19126.96.36.1991
This paper addresses method which can be used for analyzing thermal stresses of a functionally graded material(FGM) using semi-analytical approach. FGM is a nonhomogeneous material whose composition changes continuously from a metal surface to a ceramic surface. An infinite one dimensional FGM plate is considered. The temperature distribution in the FGM is obtained by approximate Green's function solution. To expedite the convergence of the solutions, alternative Green's function solution is derived and shows good agreement with results from finite difference method. Thermal stresses are calculated using temperature distribution of the plate.
Study on technique development for the solidified body of rock waste and evaluation of fracture toughness
Na, Eui-Gyun ; Yu, Hyosun ; Kim, Jin-Yong ; Lee, Jeong-Gee ; Chung, Se-Hi ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1452~1461
DOI : 10.22634/KSME-A.19188.8.131.522
The hot press apparatus to obtain the solidified rocks with 60mm of diameter against rock waste was developed, and the optimum conditions for solidification were founded out, of which were 300.deg. C of temperature and 1hr of holding time. The solidified rocks reinforced with the fibers (carbon, steel) were made by means of a hydrothermal hot press method. Fracture toughness of those was obtained using the round compact tension(RCT) specimens. Load and displacement behaviours of the solidified rocks reinforced with the fibers were dependent upon the fiber volume fraction and kind of the fibers. Strength and fracture energy of the solidified rocks with steel were much larger than those of the solidified ones with carbon because of the Bridge's effect, multiple cracking and crack branching phenomena.
Optimization of Control Parameters for Hydraulic Systems Using Genetic Algorithms
Hyeon, Jang-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1462~1469
DOI : 10.22634/KSME-A.19184.108.40.2062
This study presents a genetic algorithm-based method for optimizing control parameters in fluid power systems. Genetic algorithms are general-purpose optimization methods based on natural evolution and genetics. A genetic algorithm seeks control parameters maximizing a measure that evaluates system performance. Five control gains of the PID-PD cascade controller fr an electrohydraulic speed control system with a variable displacement hydraulic motor are optimized using a genetic algorithm in the experiment. Optimized gains are confirmed by inspecting the fitness distribution which represents system performance in gain spaces. It is shown that optimization of the five gains by manual tuning should be a task of great difficulty and that a genetic algorithm is an efficient scheme giving economy of time and in labor in optimizing control parameters of fluid power systems.
A study on CIM construction for the plastic fan design manufacturing
Choi, Yang-Ho ; Lee, Yong-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1470~1479
DOI : 10.22634/KSME-A.19220.127.116.110
In this study, the plastic fan with high efficiency and low noise was designed and the capacity of the wind and the wind pressure were analysed and verified by CAE. After designing the metallic mold using the metallic mold design data, and the the metallic mold design was reformed by analysing the process of the material stream and injection filling by CAE. Also the metallic mold cutting data were formed using the metallic mold design data. These cutting data was used to produce the fan electrode by a machining center and then this electrode were used to manufacture the metallic mold by cutting the fan cavity by an electrical spark machine. The purpose of this study is to find out the sub-optimal condition on the productivity and improvement in quality of the plastic fan by integrating a series of this process with a computer.
Characteristics of a direct system parameter estimation method
Ju, Young-Ho ; Jo, Gwang-Hwan ; Lee, Gun-Myung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1480~1490
DOI : 10.22634/KSME-A.1918.104.22.1680
A method by which the system parameter matrices can be estimated from measured time data of excitation force and acceleration has been studied. The acceleration data are integrated numerically to obtain the velocities and displacements, and the systm parameters are estimated from these data by solving equations of motion. The characteristics of the method have been investigated through its application to simulated data of 1 DOF and 2 DOF systems and experimental data measured from a simple structure. It was found that the method is very sensitive to measurement noise and the accuracy of the estimated parameters can be improved by averaging the repeatedly measured data and removing the noise. One of the main advantages of the parameter estimation method is that no a priori information about the system under test is required. The method can be easily extended to non-linear parameter estimation.
The improvement of surface roughness of cast-iron pipe
Park, Seong-Yoo ; Park, Myung-Ho ; Kim, Sung-Joon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1491~1497
DOI : 10.22634/KSME-A.1922.214.171.1241
The purpose of this research is to improve the surface roughness of cast-iron pipe porduced by the centrifugal casting. A twin-fluid atomizer of mold-wash slurry is designed for this project. New atomizer is equipped with the existing manufacturing facility to produce pipes. Cast-iron pipes (.cent.125*L3000mm) are produced and the surface roughnesses of those are analysed by UBM. The average surface roughness of new products is 6.7.mu.m while the old products of sand-resin coating method have 17.0.mu.m of average surface roughness. The surface roughness of cast-iron pipe is improved very much than before.
Influence of residual stress due to shot peening on fatigue strength and life
Lee, Jong-Gyu ; Kim, Jeong-Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1498~1506
DOI : 10.22634/KSME-A.19126.96.36.1998
Procedures are presented for influence of shot peening on fatigue strength, fatigue life and effects of shot peening are discussed from experiments were taken between shot peened and unpeened SPS5, SM45C specimens. After the residual stress on shot peened specimens was measured by X-ray diffractometer, rotating bending fatigue tests were carried out. In addition, the compressive residual stress profile was obtained by the superposition method of three stresses which is based on Al-Obaid's equation. Predicted fatigue life considering residual stress profile which was obtained by the Al-Obaid's equation and another predicted fatigue life considering residual stress profile which was measured in test were compared. For the purpose of predicting fatigue life, Morrow's equation considering the residual stress and mean stress was used.
Study on grindability of ferrite
Kim, Seong-Cheong ; Lee, Jae-U ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1507~1519
DOI : 10.22634/KSME-A.19188.8.131.527
This paper aims to clarify the effects of grinding conditions on bending strength in surface grinding of various ferrites with the resin bond diamond wheel. The main conclusions obtained were as follows. At a constant material removal rate, the strength improves with increased wheel depth of cut and decreased workpiece speed. It is desirable to grind at higher peripheral wheel speed and under the critical workpiece speed presented in this paper. Grinding the ferrite of higher brittleness, the wheel depth of cut limited to hold 50% of their inherent strength becomes lower. The effect of various grinding conditions on bending strength becomes more larger in the order of Sr, Mn-Zn and Cu-Ni-Zn. When using the diamond grain of the lower toughness, the bending strength becomes higher, and the wheel wear occurs faster. Considering both bending strength and wheel wear rate, the best concentration of wheel is 100. The ground surfaces exhibit that the fracture process during grinding becomes more brittle in the order of Sr, Mn-Zn and Cu-Ni-Zn.
Machinability of ceramic and WC-Co green compacts
Lee, Jae-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1520~1530
DOI : 10.22634/KSME-A.19184.108.40.2060
Machining pressed compacts of ceramic and WC-Co materials can be the most cost effective way of forming the bodies prior to sintering when the required number of pieces is small. In this study, in order to clarify the machinability for turning, the
and the WC-Co green compacts unsintered were machined under different cutting conditions with various tools. Absorbing chips by vacuum hose decreases tool wear. The tool wear becomes larger in the order of the ceramic, CBN and cemented carbide tools in machining the
green compacts. In machining the WC-Co green compacts, the tool wear becomes larger in the order of the ceramic, cemented carbide and CBN tools. The land of cutting edge does not affect tool wear. When machining with cemented carbide tool, the tool wear i equal cutting length is nearly identical in spite of the increase of cutting spee, and the roughness of machined surface was the best in the cutting speed of 90 m/min. The tool wear decreases with the increase of rake angle and relief angle and with the decrease of nose radius. The machined surfaces become worse with the increase of feed rate and depth of cut, and with the decrease of rake angle and relief angle. The tool wear is not affected by the feed and depth of cut.
Measurement of cutting edge ratio using vision system in grinding
Yu, Eun-Lee ; Sa, Seung-Yun ; Ryu, Bong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 21, issue 9, 1997, Pages 1531~1540
DOI : 10.22634/KSME-A.19220.127.116.111
Mordern industrial society pursues unmanned system and automation of manufacturing process. Abreast with this tendensy, production of goods which requires advanced accuracy is increasing as well. According to this, the work sensing time of dressing by monitoring and diagnosing the condition of grinding, which is th representative way in accurate manufacturing, is an important work to prevent serious damages which affect grinding process or products by wearing grinding wheel. Computer vision system was composed, so that grinding wheel surface was acquired by CCD camera and the change of cutting edge ratio was measured. Then we used automatic thresholding technique from histogram as a way of dividing grinding cutting edge from grinding surface. As a result, we are trying to approach unmanned system and automation by deciding more accurate time of dressing and by visualizing behavior of grinding wheel by making use of computer vision.