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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 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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Experimental Investigation on the Mechanial Behavior of Graphite/Epoxy Composites Under Hydrostatic Pressure
Rhee, K.Y. ; Pae, K.D. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2431~2435
DOI : 10.22634/KSME-A.1922.214.171.1241
In order to determine the effects of hydrostatic pressure on the mechanical behavior of graphite fiber reinforced composites, the modulus, fracture stress(maximum stress), and fracture strain of graphite/epoxy composites have been determined as a function of pressure. Composite specimens used in this study were 90-deg unidirectional and had a 60% fiber volume fraction. Compressive tests under five different pressure levels were conducted. The result showed the modulus measured from as initial slope of stress-strain curve increased bilinearly with pressure with a break at 200 MPa. It was also found that fracture stress and fracture strain increased in a linear fashion with pressure.
Development of Fuzzy Network Performance Manager for Token Bus Networks in Automated Factories
Lee, Sang-Ho ; Son, Joon-Woo ; Lee, Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2436~2448
DOI : 10.22634/KSME-A.19126.96.36.1996
This paper presents the development of three types of network performance manager for IEEE 802.4 token bus networks that are a part of Manufacturing Automation Protocol(MAP). The performance managers attempt to keep the average data latency below a certain level specified for each priority class. All of the three performance managers are based on a set of fuzzy rules incorporating the knowledge on the relationship between data latency and parameters of the priority mechanism. These Fuzzy Network Performance Managers(FNPMs) have been evaluated via discrete event simulation to demonstrate their efficacy.
Experimental Study on Control of Autopilot System(I)
Han, Bong-Ju ; Bae, Gyeong-Su ; Kim, Hwan-Seong ; Kim, Sang-Bong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2449~2457
DOI : 10.22634/KSME-A.19188.8.131.529
This paper presents a design method for autopilot control system in course change to the specified direction based on a robust digital servo controlmelthod incorporating the concept of the annihilator polynormial. The mathematicalmodel of ship turning motion is very complex in the view of practical control because it has time varying parameters, nonlinear and dead time terms. To apply the digital servo control method based on computer control, the model is linearized at an equilibrium point and discretized with appropriate sampling time. The control algorithm was evaluated on the basis of computer simulation for a model ship and the practical experiment was carried out with an image processing method for measurement of ship position in a water tank. The results of overall experiments show that the proposed control method will be one of good way to keep a track plotted in the map.
FEM Analysis of Closed-Die Forging of a Bevel Gear
Park, Jong-Jin ; Lee, Jung-Hwan ; Lee, Young-Sun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2458~2467
DOI : 10.22634/KSME-A.19184.108.40.2068
The rigid-plastic finite element analysis was performed for analysis of ofhot forging and cold sizing of a bevel gear. Two dimensional analysis was carried out to investigate the defect occurrence on vertical symmetric planes during hot forging and three dimensional analysis was to understand the filling behavior on horizontal planes during cold sizing. The involute curve of a tooth was approximated by a circle for convenience in the present analysis. In order to estimate the elastic deformation of the gear and dies during cold sizing, linear elastic finite element analysis was performed. Results of the analysis can be used to predict grain flows and strength distributions in the forged gear, and to design dies and an appropriate preform for the cold sizing.
Upper Bound Analysis of Plane Strain Hot Strip Rolling Process
Moon, Young-Hoon ; Chun, Myeong-Sik ; Yi, Joon-Jeong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2468~2479
DOI : 10.22634/KSME-A.19220.127.116.118
An upper bound solution is obtained to perform the process analysis of hot strip rolling process. The material flows within the roll bite at various geometries and frictional conditions are obtained from finite element analysis and the typical flow pattern which is necessary to determine the kinematically admissible velocity field is assumed. From the kinematically admissible velocity field, the upper bound energy is calculated and the rolling load, angle of neutral point and forward slip ratio at various operational conditions are obtained from upper bound energy. The process analysis of above mentioned parameters at various operational conditions have provided valuable information which is hard to obtain during rolling operation and the predicted ranges of quantitive values from these analyses lie whthin the bound of actual operational data.
Development of a Hydraulic Servo Cylinder with an Integrated Feedback Mechamism
Lee, Jae-Gyu ; Kim, Ock-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2480~2490
DOI : 10.22634/KSME-A.1918.104.22.1680
This paper presents a new type of hydraulic servo chllinder which is characterized by its simple construction and an ubtegrated feedback mechanism. Piston position of the cylinder is controlled by eletrical input and mechamical feedback deduced from its own structure. Hydraulic pressure in each cylinder room is controlled by a poppet valve. The poppet is activated by a solenoid and is linked to the piston. Solenoid input current pulls up the poppet, which results in pressure drop and thus piston motion. The piston motion generates pull down force on the poppet by the linkage and the motion stops at equilibrium. In that way the piston position is controlled by an expernal input current. Characteristics of the servo cylinder is verified by stability analysis, tranient vehavior and steady state positing for step input. Design parameter analyses have been executed by derivation of analytical approximate solutions and by computer simulations. A prototype hydraulic servo cylinder is developed and tested. The experimental results show successful function of the servo cylinder and consistency with the theoritical results.
Experimental Study of Buckling Behavior of Composite Laminates with an Embedded Delamination
Kim, Hyo-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2491~2500
DOI : 10.22634/KSME-A.1922.214.171.1241
An experimental and analytical investigation is performed to study the buckling behavior of composite laminates with an embedded delamination. It is of particular interest to veryfy whether delamination growth cddurs with continuming deformation after buckling of composite laminates with an embedded delamination. Experiments are conducted for [0/sub 4///90/sub 8//0/sub 4/]/sub r/ laminates with delamination size in which local buckling mode governs buckling. Results show that delamination growth occurs in hgigher load after buckling and is accompanid by other damage mechanisms such as splitting. Also, it is found that transverse deformation before difurcation buckling is due to initial imperfection and structure such as plate with small bending stiffness is sensitive to that.
A Study on the Active Control of Air Bearing
Lee, Jeong-Bae ; Kim, Kyung-Woong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2501~2507
DOI : 10.22634/KSME-A.19126.96.36.1991
In this paper actively controlled air bearing is investigated to overcome the defects of air bearing such as low stiffness and damping coefficients. The actively controlled air beairng is composed of an air bearing, a gap sensor, a controller, and a piezo actuator. By controlling the position of air bearing with piezo actuator, the position of floating object is controlled. In this study the proportional-Integral-Derivative controller is employed. Active air bearing is investigated numerically and experimentally. There is good agreement between the simulation and the experimental results. It is shown that the stiffness and damping characteristics and positioning experimental results. It is shown that the stiffness and damping characteristics and positioning accuracy of air bearing can be improved by means of adopting actively controlled air bearing.
Determination of the Optimum Feed Rate by a Surface Roughness Model in a Face Milling Operation
Baek, Dae-Kyun ; Ko, Tae-Jo ; Kim, Hee-Sool ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2508~2515
DOI : 10.22634/KSME-A.19188.8.131.528
Determination of an optimal feed rate is valuable in the sense of the precision and efficient machining. In this regard, a new surface roughness model for the face milling operation that considered the radial and axal runouts of the inserts in the cutter body was developed. The validity of the model was proved through the cutting experiments, and the model is able to predict the real machined surface roughness exactly with the information of the insert runouts and the cutting conditions. From the estimated surface roughness value, the maximum feed rate that obtains a maximum naterial removal rate under the given surface roughness constraint can be selected by using a bisection method. Therefore, this mehod for optimizing the feed rate can be well applied to the using a bisection method. Therefore, this method for optimizing the feed rate can be well applied to the using selsction of the cutting condition during the NC data generation in CAM.
Vibration Analysis of Rotating Cantilever Beams Considering Concentrated Mass Effect
Yoo, Hong-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2516~2523
DOI : 10.22634/KSME-A.19184.108.40.2066
The equations of motion for rotating contilever beams with a concentrated mass loated in an arbitrary position are derived. For the modeling of the concentrated mass the Dirac delta function is used for the mass density function. Parametric studies are performed with five dimensionless variables ; natural frequencies, angular velocity, hub radius, concentrated mass, and the mass location. The concentrated mass, whereverit may locate, lowers the natural frequencies of a stationaly beam. However, when the beam rotates, the natural frequencies(if they increase or decrease) are dictated by the location of the concentrated mass.
A Study on Structural Analysis for Aircraft Gas Turbine Rotor Disks Using the Axisymmetric Boundary Integral Equation Method
Kong, Chang-Duk ; Chung, Suk-Choo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2524~2539
DOI : 10.22634/KSME-A.19220.127.116.114
A design process and an axisymmetric boundary integral equation method for precise structural analysis of the aircraft gas turbine rotor disk were developed. This axisymmetric boundary integral equation method for stress and steady-state thermal analysis was improved in solution accuracy by appling an implicit technique for Cauchy principal value evaluation, a subelement technique for weak singular integral evaluation and a double exponentical integral technoque for internal point solution near boundary surfaces. Stresses, temperatures, low cycle fatigue lifes and critical speeds for the turbine rotor disk of the thrust 1421 N class turbojet engine were analysed in a pratical calculation model problem.
A 2-Node Strain Based Curved Beam Element
Ryu, Ha-Sang ; Sin, Hyo-Chol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2540~2545
DOI : 10.22634/KSME-A.1918.104.22.1680
It is well known that in typical displacement-based curved beam elements, the stiffness matrix is overestimated and as a result displacement predictions show gross error for the thin beam case. In this paper, a stain based curved beam element with 2 nodes is formulated based on shallow beam geometry. At the element level, the curvature and membrane strain fields are approximated independently and the displacement fields are obtained by integrating the strain fields. Three test problems are given to demonstrate the numerical performance of the element. Analysis results obtained reveal that the element is free for locking and very effectively applicable to deeply as well as shallowly curved beams.
A Free Vibration Analysis of Sound-Structure Interaction Plate
Lee, Dong-Ick ; O, Jae-Eung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2546~2554
DOI : 10.22634/KSME-A.1922.214.171.1246
In order to investigate the characteristics of sound-structure interaction problems, we modeled a rectangular cavity and the flexible wall of the cavity. Because the governing equations of motion are coupled through velocity terms, we could redefine them using the velocity potential. We calculated the natural frequencies of plate using orthogonal polynomial functions which satisfy the boundary conditions in the Rayleigh-Ritz Method. As the result, comparisons of theory and experiment show good agreement. and using orthogonal polynomial functions which satisfy the boundary conditions in the Rayleigh-Ritz method show useful method for sound-structure interaction problems too.
Three Dimension Car Body Measuring System Using Industrial Robots
Kim, Mun-Sang ; Cho, Kyung-Rae ; Park, Kang ; Shin, Hyun-Oh ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 8, 1996, Pages 2555~2560
DOI : 10.22634/KSME-A.19126.96.36.1995
Inspecting the dimensional accuracy of a car-body in assembly line is a very important process to assure high productivity. Now there exist two common inspecting methods in practice. One is to measure a sampled car-body with three dimensional measuring machine, and the other is to measure car-body with three dimensional measuring machine, and the other is to measure car-body in assembly line using many sensors fixed to a large jig frame. The formal method takes too long to inspect a sampled car-body of a same sort, and cannot therefore give an useful error trend for the whole production. On the other hand, the latter lacks flexibility and is very cost-intensive. By using industrial robots and sensors, an in-line Car-Body Measuring(CBM) system which ensured high flexiblity and sufficient accuracy was developed. This CBM cell operates in real production line and measures the check points by the non-contact type using camera and laser displacement sensor(LDS). This system can handle about 15 Measuring points within a cycle time of 40 seconds. A process computer controls whole process such as data acquisition file handling and data analysis. Robot arms changes in length due to ambient temperature fluctuation affecting the measuring accuracy. To compensate this error, a robot arm calibration process was developed.