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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
Editor in Chief :
Volume & Issues
Volume 20, Issue 12 - Dec 1996
Volume 20, Issue 11 - Nov 1996
Volume 20, Issue 10 - Oct 1996
Volume 20, Issue 9 - Sep 1996
Volume 20, Issue 8 - Aug 1996
Volume 20, Issue 7 - Jul 1996
Volume 20, Issue 6 - Jun 1996
Volume 20, Issue 5 - May 1996
Volume 20, Issue 4 - Apr 1996
Volume 20, Issue 3 - Mar 1996
Volume 20, Issue 2 - Feb 1996
Volume 20, Issue 1 - Jan 1996
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A Study on Stress Corrosion Cracking Evaluation with Material Degradation of High Temperature Components
Park, Jong-Jin ; Yu, Ho-Seon ; Jeong, Se-Hui ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1123~1132
DOI : 10.22634/KSME-A.19220.127.116.113
It has been reported that high temperature structural components represent the phenomenon of material degradation according to a long term service under high temperature and pressure. Especially, fossile power plant components using the fossil fuel and heavy oil are affected by dewpoint corrosion of
produced during a combustion. Therefore, the service materials subjected to high temperature and pressure may occur the stress corrosion cracking. The object of this paper is to investigate SCC susceptibility according to the material degradation of the high temperature structural materials in dewpoint corrosive environment-
.The obtained results are summarized as follows : 1) In case of secondary superheater tube, the fractograph of dimple is observed at the concentration of
-5%. When the concentration of
is above 10%, the fracture mode is shifted from a transgranular fracture to an quasi-intergranular fracture according to the increment of concentration. 2) In the relationship between [
and SCC susceptibility, it is confirmed that the greater material degradation degree is, the higher SCC susceptibility is. In addition, it can be known that SP test is useful test method to evaluate SCC susceptibility for high temperature structural components. 3) When [
is above 17
the SCC fracture behavior is definitely observed with SCC susceptibility of above 0.4.
Shape Estimation for the Control of Composite Smart Sstructure Using Piezoceramics
Ha, Seong-Gyu ; Jo, Yeong-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1133~1145
DOI : 10.22634/KSME-A.1918.104.22.1683
A method is proposed to predict the deformed shape of the structure subjected to the unknown external loads using the signal from the piezoceramic sensors. Such a shape estimation is based on the linear relationship between the deformation of structure and the signal from sensor, which is calculated using finite element method. The deformed shape is, then calculated using the linear matrix and the signals from the piezoceramic sensors attached to the structures. For the purpose, a structural analysis program is developed using a multi-layerd finite element of 8 nodes with 3 displacement and one voltage degrees of freedom at each node. The multiple layers with the different material properties can be layered within the element. The incompatible mode with the element is found to be crucial to catch the bending behavior accurately. The accuracy of the program is, then, verified by being compared with the experimental results performed by Crawley. The proposed shape estimation method is also verified for the different loads and sensor size. It is shown that the results of shape estimation method using the linear matrix well predicts the deflections compared with those of finite element method.
A Study on Mean Coefficient of Separation during Compression Molding of Fiber-Reinforced Thermoplastics
Kang, Geon ; Jo, Seon-Hyeong ; Lee, Dong-Gi ; Kim, Lee-Gon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1146~1153
DOI : 10.22634/KSME-A.1922.214.171.1246
The properties of FRP(fiber-reinforced plastics) depend not only on the characteristics of the matrix but also on the structure of fiber mat and the fiber type of reinforcement. Therefore it is very important to study the characteristics of reinforcement and matrix. In this paper, a method is proposed which can be used to measure the mean coeffcient of separation for the press molding of FRP, and the mean equivalent coefficient of separation is obtained from the separation coefficient. And the relationship between the mean equivalent coefficient of separation and the structure of fiber mat is discussed. The effects of corrlelation coefficient between separation and orientation on the mean equivalent coefficient are also presented.
Evaluation of Joint Reaction Forces for a Hydraulic Excavator Subjected to a Critical Load
Kim, Oe-Jo ; Yu, Wan-Seok ; Yun, Kyeong-Hwa ; Gang, Ha-Geun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1154~1163
DOI : 10.22634/KSME-A.19126.96.36.1994
This paper presents a three dimensional modeling and dynamic anlaysis of a hydraulic excavator. An excavator is composed of a ground, an under-frame, two idlers, two spockets, an upper-frame, a boom, an arm, a bucket two yokes, two connecting rods, two boom cylinders, an arm cylinder, and a bucket cylinder. Each cylinder is modeled with two separate bodies which are linked to each other by a translational joint. The three dimensioanl model of the excavator consists of 22 bodies and each body is assumed as rigid. This paper suggested the maximum lifting capability, a critical load and reaction forces at joints form the DADS simulation. It was presumed that the reaction forces due to a critical load are three times bigger than those due to the maximum lifting capacity.
Development of a Noncontacting 6 DOF Micro-Postioner Driven by Magnetic Force-Design, Modeling and Control-
Choi, Kee-Bong ; Park, Kyi-Hwan ; Kim, Soo-Hyun ; Kwak, Yoon-Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1164~1176
DOI : 10.22634/KSME-A.19188.8.131.524
A magnetically levitated micro-positioner is implemented to avoid mechanical friction and increase precision. Since magnetic levitation system is inherently unstable, most concern is focused on a magnetic circuit design to increase the system dynamic stability. For this, the proposed levitation system is constructed by using an antagonistic structure which permits a simple design and robust stability. From the dynamic equations of motion, it is verified that the proposed magnetically levitated system is decoupled in 6 degree-of-freedom motion. Experimental results are presented in terms of time response and accuracy.
Analysis of Creep Crack Growth at High-Temperature Components by Diffusive Growth Model of Grain Boundary Cavities (I)-Effect of Grain Boundary Cavitation on Stress Field and Crack Growth Rate-
Jeon, Jae-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1177~1185
DOI : 10.22634/KSME-A.19184.108.40.2067
The crack growth under creep condition is one of the major damage mechanisms which determines remaining life of the component operating at high temperatures. In this paper, the creep crack growth by grain boundary cavitation is studied, which is frequently observed failure mechanism for creep brittle materials. As a result of diffusive growth of creep cavities, it is shown that the crack-tip stress field is modified from the original stress distribution by the amount of singularity attenuation parameter which is function of crack growth rate and material properties. Also, the stress relaxation at crack-tip results in the extension of cavitating area by the load dump effect to meet the macroscopic force equilibrium conditdion.
입계기공의 확산성장 모델을 이용한 고온 기기의 크립균열전파 해석 (2)
Jeon, Jae-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1186~1193
DOI : 10.22634/KSME-A.19220.127.116.116
The analytic solution of the stress field at creep crack in the presence of grain boundary caviation is to be obtained by solving the governing equation which was derived through the previous paper. The complex integral technique is used to slove the singular integral equation. under the help of the information about stress behaviors at the ends of integral region know by numerical solution. The resultant stress disstribution obtained shows the relaxed crack-tip singularity of
due to the intervention of cavitation effect, otherwise, it should assumed to be
singularity of linear elastic fracture mechanics with no cavitation.
입계기공의 확산성장 모델을 이용한 고온 기기의 크립균열전파해석(3)
Jeon, Jae-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1194~1201
DOI : 10.22634/KSME-A.1918.104.22.1684
For the case of creep-fatigue interaction, the damage zone developed in front of the growing crack-tip during creep regime is important because it can affect the damage mechanism to be occured by the following fatigue load. These are studied in theis paper through proper consideration of the cavitiy-size dependent sintering stress which is approximated by polynomials. It is shown that the inclination of reversed damage zone size with respect to the applied load parameter can be explained by considering realistic sintering stress distribution. However, the resultant stress field has
singularity, regardliss of the profile of variable sintering stress, which is the same to that case solved for constant sintering stress.
Development of Control System for Transversal Temperature of Strips in Hot Strip Mills
Choi, Jae-Chan ; Lee, Sung-Jin ; Park, Bong-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1202~1215
DOI : 10.22634/KSME-A.1922.214.171.1242
In this study, in order to achieve the uniformity of mechanical properties and microstructures of a hot-rolled coil in the transversal direction, the edge mask device is newly device is newly developed and installed at the upper laminar-flow cooling head in the run out table, which controls the transversal temperature of strip with enco panel and bar edge heater. The device that is transversally movable prevents the temperature drop of strip edge by blocking the cooling water into the strip edge. So, the pattern of edge mask set-up condition of the device was derived by analyzing the characteristics of strip temperature and mechanical properties according to the on-line application of edge mask.
A Study on the Cutting Characteristics of Glass Fiber Reinforced Plastics by Tool Materials and Type
An, Sang-Ook ; Noh, Sang-Lai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1216~1224
DOI : 10.22634/KSME-A.19126.96.36.1996
In the use of glass fiber reinforced plastics it is often necessary to cutting the components, but the cutting GFRP is often made difficult by the delamination of composites and the short tool life. In this paper, the machinability of GFRP by mean of tool materials and type was experimentally investigated. By proper selection of cutting tool material and type excellent machining of this workpiece is achieved. The surface quality relate closely with the feed rate and cutting tools.
Vibraiton and Power Flow Analysis for the Branched Piping System by Wave Approach
Koo, Gyeong-Hoe ; Park, Yun-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1225~1232
DOI : 10.22634/KSME-A.19188.8.131.525
In this paper the vibration and power flow analysis for the branched piping system conveying fluid are performed by wave approach. The uniform straight pipe element conveying fluid is formulated using the dynamic stiffness matrix by wave approach. The branched piping system conveying fluid can be easily formulated with considering of simple assumptions of displacements at the junction and continuity conditions of the pipe internal flow. The dynamic stiffness matrix for each uniform straight pipe element can be assembled by using the global assembly technique using in conventional finite element method. The computational method proposed in this paper can easily calculate the forced responses and power flow of the branched piping system conveying fluid regardless of finite element size and modal properties.
A Measurement Method of Internal Defects of Pressure Vessles by Using Real-Time Holographic Interferometry
Moon, Sang-Joon ; Kang, Young-June ; Baik, Sung-Hoon ; Kim, Cheol-Jung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1233~1240
DOI : 10.22634/KSME-A.19184.108.40.2063
Conventional measurement methods using ultrasonic wave or x-ray, eddy current for non-destructive testing(NDT) in nuclear power plants and other industrial plants have been utilized as the method of contact with objects to be inspected. For this reason these methods require relatively much time and inspection area is limited by the location of probe or film. But holograpic interferometry which is a non-contact optical measurement method using a coherent light source has an advantage that quantative measurement can be performed at a time. In this paper a new method using realtime holographic interfreometry and image processing for detecting internal flaws of pressure vessels is presented.
The Probabilistic Analysis of Fatigue Damage Accumulation Behavior Using Markov Chain Model in CFRP Composites
Kim, Do-Sik ; Kim, In-Bai ; Kim, Jung-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1241~1250
DOI : 10.22634/KSME-A.19220.127.116.111
The characteristics of fatigue cumulative damage and fatigue life of 8-harness satin woven CFRP composites with a circular hole under constant amplitude and 2-level block loading are estimated by Stochastic Makov chain model. It is found in this study that the fatigue damage accumulation behavior is very random and the fatigue damage is accumulated as two regions under constant amplitude fatigue loading. In constant amplitude fatigue loading the predicted mean number of cycles to a specified damage state by Markov chain model shows a good agreement with the test result. The predicted distribution of the fatigue cumulative damage by Markov chain model is similar to the test result. The fatigue life predictions under 2-level block loading by Markov chain model revised are good fitted to the test result more than by 2-parameter Weibull distribution function using percent failure rule.
Analysis on the Nonlinear Vibration Characteristics of a Belt Driven System
Kim, Seong-Geol ; Lee, Sin-Yeong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1251~1262
DOI : 10.22634/KSME-A.1918.104.22.1681
In this paper, a mathematical model for a belt driven system is proposed to analyse the vibration characteristics of the driving units with belts and the free and forced vibraiton anlyses are carried out. The mathematical model for a belt-driven system includes belts, pulleys, spindle and bearings. By using Hamilton's principle, four nonlinear governing equations and twelve nonlinear boundary conditions are derived. To linearize and discretize the nonlinear governing equations and boundary conditions, the perturbation method and Galerkin method are used. Also, the free vibration analyses for various parameters of a belt driven system, which are the tension of a belt, the length of a belt, the material properties of belts, the velocity of a velt and the mass of pulley are made. The forced vibration analyses of the system are performed and the dynamic responses for main parameters are anlysed with a belt driven system.
An Experimental Study on the Evaluaiton of Elastic-Plastic Fracture Toughness under Mixed Mode I-II-III Loading Using the Optical PSD
Kim, Hei-Song ; Lee, Choon-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1263~1274
DOI : 10.22634/KSME-A.1922.214.171.1243
In this paper, as elastic-plastic fracture toughness test under mixed mode loading was proposed using a single edge-cracked specimen subjected to bending moment(M), shearing force(F), and twisting moment(T). The J-integral of a crack in the specimen is expressed in the form J=
+ $J_II$, where
are the components of mode I, mode II and mode III deformation, respectively.
can be estimated from M-
;crack opening angle), F-U(U; crack shear displacement) and T-
;crack twisting angle). In order to obtain the the M<-TEX>$\theta$, F-U and T-
diagram inreal time, a new deformaiton gage for mixed mode loading was proposed using the optical position sensing device(PSD). The elastic-plastic fracture toughness test was carried out with an aluminum alloy. The loading apparatus was designed and manufactured for this experiment. For the loading condition of the crack initatio in the mixed mode, the MMT -3(mode I+ mode II+ mode III) has the lowest values out of the all specimens. This implies that MMT-3 is possible of the crackinitation at lower load, if the specimen acts on together with the torque under the same loading condition. An elastic-plastic fracture toughness test using the PSD brings a successful experimentation in measuring the crack deformation(mode I+ mode II+ mode III).
The Problem of Collinear Cracks in a Layered Half-Plane with a Functionally Graded Nonhomogeneous Interfacial Zone
Jin, Tae-Eun ; Choe, Hyung-Jip ; Lee, Kang-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1275~1289
DOI : 10.22634/KSME-A.19126.96.36.1995
The plane elasticity problem of collinear cracks in a layered medium is investigated. The medium is modeled as bonded structure constituted from a surface layer and a semi-infinite substrate. Along the bond line between the two dissimilar homegeneous constituents, it is assumed that as interfacial zone having the functionally graded, nonhomogeneous elastic modulus exists. The layered medium contains three collinear cracks, one in each constituent material oriented perpendicular to the nominal interfaces. The stiffness matrix formulation is utilized and a set of homogeneous conditions relevant to the given problem is readily satisfied. The proposed mixed boundary value problem is then represented in the form of a system of integral equations with Cauchy-type singular kernels. The stress intensity factors are defined from the crack-tip stress fields possessing the standard square-root singular behavior. The resulting values of stress intensity factors mainly address the interactions among the cracks for various crack sizes and material combinations.
Hourglass Control in Rigid-Plastic Finite Element Analysis
Gang, Jeong-Jin ; O, Su-Ik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1290~1300
DOI : 10.22634/KSME-A.19188.8.131.520
The finite element method, based on rigid-plastic formulation, is widely used to simulate metal forming processes. In order to improve the computational efficiency of the rigid-plastic FEM, one-point integration is used to evaluate the stiffness matrix with four-node rectangular elements and eight-node brick elements. In order to control the hourglass modes, hourglass strain rate components were introduced and included in the effective strain rate definition, Numerical tests have shown that the proposed one-point integration scheme reduces the stiffness matrix evaluation time without deteriorating the convergence behavior of Newton-Raphson method. Simulations of a ring compression, a plane-strain closed-die forging and the three-dimensional spike forging processes were carried out by using the proposed integration method. The simulation results are compared to those obtained by applying the conventional integraiton method in terms of the solution accuracy and computational efficiency.
Effect of Volume Fraction on Mechanical and Fatigue Crack Growth Properties of SiC Particle Reinforced AL Alloy Composites
Gwon, Jae-Do ; An, Jeong-Ju ; Mun, Yun-Bae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1301~1308
DOI : 10.22634/KSME-A.19184.108.40.2061
In order to save the energy and protect the environment, it were studied about ecomaterials with the developed countries as central figure. In the Metal Matrix Composites(MMCs), this trends appeared the development of the MMCs which had excellent mechanical properties in spite of the low volume fraction of reinforcement. Therefore, in this study, fatigue crack growth test, tensile and hardness test were conducted in order to investigate the mechanical and fatigue properties of 5 %, and 10 %
/Al composites. As the results, in the tensile and hardness test, tensile strength and hardness increased but fatigue crack growth rate decreased with
/Al volume fraction. And in the view of fatigue failured surface through the SEM, fatigue crack initiated around the SiC particle and in low
regions, fatigue creck detoured the SiC particle but crack propagated through the SiC particle in the high
Classification of Welding Defects in Austenitic Stainless Steel by Neural Pattern Recognition of Ultrasonic Signal
Lee, Gang-Yong ; Kim, Jun-Seop ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1309~1319
DOI : 10.22634/KSME-A.19220.127.116.119
The research for the classification of the natural defects in welding zone is performd using the neuro-pattern recognition technology. The signal pattern recognition package including the user's defined function is developed to perform the digital signal processing, feature extraction, feature selection and classifier selection, The neural network classifier and the statistical classifiers such as the linear discriminant function classifier and the empirical Bayesian calssifier are compared and discussed. The neuro-pattern recognition technique is applied to the classificaiton of such natural defects as root crack, incomplete penetration, lack of fusion, slag inclusion, porosity, etc. If appropriately learned, the neural network classifier is concluded to be better than the statistical classifiers in the classification of the natural welding defects.
Static and Natural Vibration Analyses of Bending Problems Using 5-Node Equivalent Element
Gwon, Young-Doo ; Yun, Tae-Hyeok ; Jeong, Seung-Kap ; Park, Hyeon-Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1320~1332
DOI : 10.22634/KSME-A.1918.104.22.1680
In the present study, we consider modified 5-node equivalent solid element which has smallest degree of freedom among 2-dimensional solid elements accounting bending deformation as well as extensional and shear deformations, We shall investigate static and dynamic characteristics of this element, which is very effective in thin beam, thick beam, large displacement problems, beam of variable thickness, and asymmetrically stepped beam, etc., as well as relatively simple problems of beam. The degree of freedom of this element is 10, which is smaller than 18 of 9-node element, 16 of 8-node elemtns, 12 of modified 6-node element and Q6 element. Therefore, this element is expected to broaden the effective range of application of the solid elements in the bending problems further.
Software Development for Glass-Bulb Automatic Design Integrated System Using Design Axiom
Do, Sung-Hee ; Park, Gyung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1333~1346
DOI : 10.22634/KSME-A.1922.214.171.1243
As the automation system in manufacturing field works more efficientely, the automation scheme is applied to many areas. In order to reduce the entire manufacturing, cost the design process must be automated. However, design process is so complicated, it is very difficult to construct the design automation system. The axiomatic approach to design provides a general theoretical framework for all design fields, including mechanical design. The key concepts of axiomatic design are : the existence of domains, the characteristic vectors within the domains that can be decomposed into hierarchies through zigzagging between the domains, and the design axioms. Using this approach, the glass bulb design process was analyzed and the design automation software was developed. Through menu display, a user can select or furnish the design input and generate the drawing with ease.
Hygrothermal Fracture Analysis of Plastic IC Package in Reflow Soldering Process
Lee, Kang-Yong ; Lee, Taek-Sung ; Lee, Kyung-Seob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1347~1355
DOI : 10.22634/KSME-A.19126.96.36.1997
The purpose of this paper is to evaluate the delamination and fracture integrity of the IC plastic package under hygrothermal loading by stress analysis and fracture mechanics approaches. The plastic SOJ package with a dimpled diepad under the reflow slodering process of IR heating type is considered. On the package without a crack, the stress variation according to the change of the design variables such as the material and shape of the package is calculated and the possibility of delamination is considered. For the model fully delaminated between the chip and diepad, J-integrals are calculated for the various design variables and the fracture integrity is discussed. From the results, optimal design values of variables to prevent the delamination and fracture of IC package are obtained. In this study, FDM program to obtain the vapor pressure from the content of moisture absorbed into the package is developed.
A Probabilistic Study on Thickness Effect of Fracture Toughness in Heterogeneous Brittle Materials
Kim, Am-Kee ; Koh, Sung-Wi ; Jung, Gyoo-Dong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 1356~1362
DOI : 10.22634/KSME-A.19188.8.131.526
Fracture toughness of heterogeneous brittle materials such as poly crystalline ceramics used to present the size (thickness) effect as well as statistically distributed results. There is belief that both(size effect and scatter) must be associated with each other. However, no generally accepted theory has been established so far. Using statistical approach, a probabilistic modeling for the fracture toughness which describes the thickness effect was attempted in this paper, Weibull distribution of specific fracture energy(SFE)at local areas and Griffith criterion are applied to the model. In addition, the newly developed model was verified with experimental results of alumina.
A Study on High Temperature Low Cycle Fatigue Crack Growth Modelling by Neural Networks
Ju, Won-Sik ; Jo, Seok-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 4, 1996, Pages 2752~2759
DOI : 10.22634/KSME-A.19184.108.40.20652
This paper presents crack growth analysis approach on the basis of neural networks, a branch of cognitive science to high temperature low cycle fatigue that shows strong nonlinearity in material behavior. As the number of data patterns on crack growth increase, pattern classification occurs well and two point representation scheme with gradient of crack growth curve simulates crack growth rate better than one point representation scheme. Optimal number of learning data exists and excessive number of learning data increases estimated mean error with remarkable learning time J-da/dt relation predicted by neural networks shows that test condition with unlearned data is simulated well within estimated mean error(5%).