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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
Journal Basic Information
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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A Learning Algorithm for Optimal Fuzzy Control Rules
Chung, Byeong-Mook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 399~407
DOI : 10.22634/KSME-A.19184.108.40.2069
A fuzzy learning algorithm to get the optimal fuzzy rules is presented in this paper. The algorithm introduces a reference model to generate a desired output and a performance index funtion instead of the performance index table. The performance index funtion is a cost function based on the error and error-rate between the reference and plant output. The cost function is minimized by a gradient method and the control input is also updated. In this case, the control rules which generate the desired response can be obtained by changing the portion of the error-rate in the cost funtion. In SISO(Single-Input Single- Output)plant, only by the learning delay, it is possible to experss the plant model and to get the desired control rules. In the long run, this algorithm gives us the good control rules with a minimal amount of prior informaiton about the environment.
Design, Fabricaiton and Testing of a Piezoresistive Cantilever-Beam Microaccelerometer for Automotive Airbag Applications
Ko, Jong-Soo ; Cho, Young-Ho ; Kwak, Byung-Man ; Park, Kwan-Hum ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 408~413
DOI : 10.22634/KSME-A.19220.127.116.118
A self-diagnostic, air-damped, piezoresitive, cantilever-beam microaccelerometer has been designed, fabricated and tested for applications to automotive electronic airbag systems. A skew-symmetric proof-mass has been designed for self-diagnostic capability and zero transverse sensitivity. Two kinds of multi-step anisotropic etching processes are developed for beam thickness control and fillet-rounding formation, UV-curing paste has been used for sillicon-to-glass bounding. The resonant frequency of 2.07kHz has been measured from the fabricated devices. The sensitivity of 195
/g is obtained with a nonlinearity of 4% over
50g ranges. Flat amplitude response and frequency-proportional phase response have been obserbed, It is shown that the design and fabricaiton methods developed in the present study yield a simple, practical and effective mean for improving the performance, reliability as well as the reproducibility of the accelerometers.
Kinimatic Analysis of a New Clss of 6-DOF Parallel Manipulator
Byun, Yong-Kyu ; Jo, Hyung-Suck ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 414~430
DOI : 10.22634/KSME-A.1918.104.22.1684
In this paper, a new kinematic structure of a parallel manipulator with six Cartesian degrees of freedom is proposed. It consists of a platform which is connected to a fixed base by means of 3-PPSP(parameters P, S denote the prismatic, spherical joints) subchains. Each subchain has a link which is concected to a passive prismatic joint at the one end and a passive spherical joint at the other. The spherical joint is then attached to perpendicularly arranged prismatic actuators which are fixed at the base. The spherical joint is then attached to perpendicularly arranged prismatic actuators which are fixed at the base. This arrangement provides a basis to control all six Cartesian degrees of motion of the platform in space. Due to its efficient architecture, the colsed-form solutions of the inverse and forward kinematics can be obtained. As a consequence, this new kinematic structure can be servo controlled using simple inverse kinematics becaese forward kinematics allows for measuring the platform's position and orientation in Cartesian space. Furthermore, the proposed structure provides an effective functional workspace. Series of simulations are performed to verify the results of the kinematics analyses.
A Study on the Design Theory of a Mechanical System : Using a Washing Machine Transmission as a Model
Cheon, Gil-Jeong ; Kim, Wan-Du ; Han, Dong-Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 431~439
DOI : 10.22634/KSME-A.1922.214.171.1241
New design principles nad necessary conditions for a mechanical system have been suggested to be kept in the design process using a washing machine transmission as a model. The necessary conditions are funcitnal requirement condition and spatial arrangement condition. The design principles to satisfy the necessary conditions are the principle of sequence and the principle of expansion. Decision sequence for state variables and design varibles of various mechanicla elements have been formulated. New automatic design program for washing machine transmission has been developed observing the necessary conditions and design principles investigated in this study. It was verified to be very effective to follow the design conditions, principles nad formulated decision sequence in mechanical system design process.
Finite Element Analysis of Punch Forming of Superplastic Materials
Huh, Hoon ; Lee, Ki-Seok ; Choi, Yeong-Jun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 440~449
DOI : 10.22634/KSME-A.19126.96.36.1990
Superplastic punch forming of sheets is simulated by a finite element method to obtain the optimal punch speed and the related deformed shapes. The punch forming has an advantage of guaranteeing the desired accuracy inside a product and controlling the thichness of a deformed sheet more accurately than blow forming. The finit element code developed is associated with the contact algorithm and the control algorithm of punch speed for the optimum forming. The simulation demonstrates that the variation of the thichness in a blank sheet affects the punch speed and the final distribution of the thichness in a product. The analysis proposes that a ring-typed thichness controller is very effective in controlling the thichness of a deformed sheet appropriately.
Numerical Analysis of Stress Field around Crack Tip under Impact Load
Hwang, Gap-Woon ; Cho, Kyu-Zong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 450~460
DOI : 10.22634/KSME-A.19188.8.131.520
To investigate the effect of stress wave propagation for crack tip, impact responses of two-dimensional plates with oblique cracks are investigated by a numerical method. In the numerical analysis, the finite element method is used in space domain discretization and the Newmark constant acceleration algorithm is used in time integration. According to the numerical results from the impact response analysis. it is found that the stress fields are bisected at the crack surface and the parts of stress intensity are moved along the crack face. The crack tip stress fields are yaried rapidly. The magnitude of crack tip stress fields are converted to dynamic stress intensity factor. Dynamic sress intensity factor appears when the stress wave has reached at the crack tip and the aspect of change of dynamic stress intensity factor is shown to be the same as the part of the flow of stress intensity.
Study on the Relationship between Plastic Deformation and Crystal Grain Change in Warm Forging
Je, Jin-Su ; Kim, Jae-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 461~472
DOI : 10.22634/KSME-A.19184.108.40.2061
The relationship between plastic deformation and crystal grain change in warm forging processes of SM10C carbon steel is studied. If the carbon steel is deformed at warm forging temperature(about recrystallization range), material properties are changed due to microstructural chanre of the crystal grain and cementite of the internal part. Some experimental values are investigated in terms of the elliptic degree of cementite, the grain size of cementite and ferrite grain size. When plastic deformation proceeds, the elliptic degree of cementite becomes larger and the grain size of cementite particle becomes small. In addition, the size of ferrite grain becomes fines by recrystallization. The elliptic degree of cementite has a considerable effect on formability. The distribution of effective strain in the forging was calculated by the rigid visco-plastic FEM analysis. The effective strain distribution obtained from the FEM simulation is compared with the experimental result, At the level of effective strain 0.3, dynamic recovery and dynamic recrystallization begin and at the level of over 2.5, the organization of material has better internal structure that is suitable for the following cold forming.
Reliability Engineering Approach to Fatigue Crack Growth Rate Under Random Loading Using DC Eletrical Potential Method
Bae, Sung-In ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 473~480
DOI : 10.22634/KSME-A.19220.127.116.113
Automatic fatigue crack length measuring system using DC electrical potential method and the system control program for automatic fatigue testing under random load condition were made in this study. And using these system and control program, fatigue tests were executed under constant and random load condition. As the result, the propagation of crack in random loading can be represented Paris equaiton and log normal probability function. But constant and random load test show different crack propagation properties.
Design, Fabrication and tTsting of a Microswitch Using Snap-through Buckling Phenomenon
Go, Jeung-Sang ; Cho, Young-Ho ; Kwak, Byung-Man ; Park, Kwan-Hum ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 481~487
DOI : 10.22634/KSME-A.1918.104.22.1681
A snapping-beam microswitch has been designed, fabricated and tested. From a design analysis, necessary and sufficient conditions for a snap-through switching fouction have been derived for a clamped shallow beam. The necessary condition has resulted in a geometric relation, in which the ratio of beam thickness to initial beam deflection plays a key role in the snapping ability. The sufficient condition for the snapping action has been obtained as a function of the inertia force due to applied acceleration, and the electrostatic force, adjustable by an inter-electrode voltage. For experimental investigations, a set of microbeams of silicon dioxide/
silicon bimorphs have been fabricated. Geometric size and mechanical behavior of each material film have been measured from on-chip test structures. Estimated and measured characteristics of the fabricated devices are compared.
Coupled Thermo-Viscoplastic Three Dimensional Finite Element Anaysis of Compression Molding of Sheet Molding Compound
Kim, Soo-Young ; Im, Yong-Taek ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 488~499
DOI : 10.22634/KSME-A.1922.214.171.1248
SMC(Sheet molding compound) is a thermosetting material reinforced with chopped fiberglass. The compression molding of SMC was analyzed based on a rigid thermo-viscoplastic approach using a three dimensional finite element program coupled with temperatures. Only the temperature analysis part was tested in this paper by solving one-dimensional heat transfer problem and comparing with the exact solutions available in the literature. Based on this comparison the program was proved to be valid and was further applied in solving compression molding of SMC between flat dies. To investigate the usefulness of a rigid thermo-viscoplastic approach in the compression molding analysis of SMC charge, compression of rectangular shaped SMC charge at plane strain and three dimensionalde formation condition was analyzed under the same condition as given in the literature. From this comparison it was found out that the rigid thermo-viscoplastic approach was useful in analyzing SMC compression molding between flat dies.
Modeling and Control of an Engine Mount Using ER Fluids and Piezoactuators
Choi, Seung-Hoon ; Choi, Young-Tai ; Choi, Seung-Bok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 500~510
DOI : 10.22634/KSME-A.19126.96.36.1990
This paper presents a new prototype of an engine mount for a passenger vehicle featuring ER(elector-rheological) fluids and piezoactuators. Conventional rubber mounts and various types of passive or semi-active hydraulic engine mounts have their own functional aims on the limited frequency band in the board engine operating frequency range. However, the proposed engine mount covers all frequency range of the engine operation. A mathematical model of the proposed engine mount is derived using the bond graph method which is inherently domain, the ER fluid is activated upon imposing electric field for vibration isolation while the piezoactuator. Computer control electric fluid for the ER fluid H.inf. cotrol technique is adopted for the piezoactuator. Computer simulation is undertaken in order to demonstrate isolation efficiency of the engine mount over wide operating frequency range.
A Study on Statistical Nature of CFRP Strength Data
Kim, Seon-Jin ; Lee, Sang-Guk ; Nam, Ki-Woo ; Oh, Sae-Kyoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 511~519
DOI : 10.22634/KSME-A.19188.8.131.521
An investigation was conducted to study the statistical nature of tensile strength and static fracture toughness of carbon fiber reinforced plastics(CFRP) materials. A good understanding of statistical aspects of strength data is essential for the successful application of such materials because these composites unpossess material uniformity as compared with conventional metallic materials. In this paper, a statistical approach based on Weibull distribution was applied to the test data to evaluate the dispersion in the tensile strength and static fracture toughness by the change of stacking method and test temparature of the CFRP materials.
High Temperature Flexural Strengths of the Ceramic-Metal Brazed Joints
Lee, Su-Jeong ; Jeong, Myung-Yeong ; Lee, Dai-Gil ; Goo, Hyung-Hoi ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 520~528
DOI : 10.22634/KSME-A.19184.108.40.2060
Four point bending tests of the brazed joint composed of sintered silicon nitride and 0.2% carbon steel with Cusil ABA filler which were fabricated at 86
were performed at temperatures, 25, 100, 200, 300, 400, 50
From the experiments, the maximum bending strength was measured at 30
From the 3D FE analysis of the residual stress of the brazed joint, it was revealed that the thermally induced residual stresses were minimized when the environmental temperature was 35
Considering the degradation of the filler material at high temperatures, it was calculated that the maximum bending strength of the brazed joint occured just below the temperature of the minimum thermal residual stress and the thermal residual stress was the dominative parameter of the brazed joint.
Effect of Crack Tip Constraint on the Fracture Resistance Curve in CT Specimen with Same Thickness
Jo, Yeon-Je ; Jang, Yun-Seok ; Seok, Chang-Seong ; Kim, Yeong-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 529~539
DOI : 10.22634/KSME-A.19220.127.116.119
Fracture resistance(J-R) curves, which are used for elastic-plastic fracture mechanics analyses, are known to be dependent on the specimen geometry. The objective of this paper is to investigate the effect of crack tip constraint an the J-R curves in CT specimens. Fracture toughness tests on CT specimens with varying planform size were performed and test results showed that the J-R curves were increased with an increase in the planform size. Finite element analysis were also performed and the numerical results showed that this experimental phenomenon was probably due to the relaxation of crack tip constraint resulting from the stress triaxiality.
Robust Force Control of Pneumatic Manipulator
Park, Jeong-Gyu ; Noritsugu, Toshiro ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 540~552
DOI : 10.22634/KSME-A.1918.104.22.1680
In this paper, a compensation method of disturbance using a disturbance observer is proposed for a force control of a pneumatic robot manipulator. The generated torque by a pneumatic actuator can be estimated based on the pressure signals. The inner torque control system is constructed by feeding back the generated torque to improve the dynamic characteristics of the actuator. In order to reduce the influence of disturbances comprising friction torque, parameter variations of plant and environment and so on, the reaction torque control system is constructed with a disturbance observer which estimates the disturbances based on the reference input to the inner torque control system and the reaction torque sensed with a forced sensor. From some simulations and experiments, it is confirmed that the proposed control system is effective to improve the robustness for the friction torque and the parameter change of object in the force control of a pneumatic robot manupulator.
Automatic Mesh Generation by Delaunay Triangulation and Its Application to Remeshing
Jeong, Hyeon-Seok ; Kim, Yong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 553~563
DOI : 10.22634/KSME-A.1922.214.171.1243
An algorithm for automatic mesh generation of two-dimensional arbitrary planar domain is proposed by using Delaunay triangulation algorithm. An efficient algorithm is proposed for the construction of Delaunay triangulation algorithm over convex planar domain. From the definition of boundary, boundary nodes are first defined and then interior nodes are generated ensuring the Delaunay property. These interior nodes and the boundary nodes are then linked up together to produce a valid triangular mesh for any finite element analysis. Through the various example, it is found that high-quality triangular element meshes are obtained by Delaunay algorithm, showing the robustness of the current method. The proposed mesh generation scheme has been extended to automatic remeshing, which is applicable to FE analysis including large deformation and large distortion of elements.
Measurement Method of the Vibration Mode Shapes Using Electro-Optic Holographic Interferometry
Choi, Jang-Seob ; Kang, Young-June ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 564~574
DOI : 10.22634/KSME-A.19126.96.36.1994
This paper describes as Electronic Speckle Pattern Interferometry system which has been designed for measuring vibration patterns and quantitative measurement of vibration amplitude fields by using the time average method on a object. Visbility of fringe patterns is more improved by using the phase stepping and frame average method to reduce speckle and electric noise. And a bias vibration is introduced into the reference beam to shift the
fringes so that fringe shift algorithms can be used to determine vibration amplitude. The experimental results are compared to those of the FFT analyzer and the FEM model analysis.
Development of Nuclear Piping Integrity Expert System(I) - Evaluation Method RecomMendation and Material Properties Inference -
Kim, Yeong-Jin ; Seok, Chang-Seong ; Choe, Yeong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 575~584
DOI : 10.22634/KSME-A.19188.8.131.525
The objective of this paper is to develop an expert system for nuclear piping integrity. This paper describes the selection methodology of integrity evalution method and the inference of material properties. To select the integrity evaluation method, the weight factor for respective material properties was obtained by the sensitivity analysis of the effect of material properties on integrity evaluation method. Subsequently the possession ratio for respective integrity evaluation method was computed, and the most appropriate integrity evaluation method for given input information is selected. In the material properties inference, stress-strain curves and J-R curves were predicted from tensile properties such as yield strength and tensile strength.
Dynamic Analyis of Long Distance Belt Conveyor During Starting and Stopping
Kim, Won-Jin ; Park, Tae-Geon ; Lee, Shin-Sup ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 585~593
DOI : 10.22634/KSME-A.19184.108.40.2065
According to the considerable increase of the length of belt conveyors, the dynamic analysis of systme becomes necessary to consider the variation of tensions and transient motion of components during starting and stopping of conveyor. The mathematical model of system is derived using the lumped parameter method. The input driving force is represented with two functions of time and pulley speed to count the characteristics of motor and fluid coupling. An example system was studied with 14 km in the distance of carrying. At head, it has two drivers and one gravity take-up and at tail ond driver and one power winch take-up. In the example, the transient tensions and responses, calculated using two cases of driving force, are mutually compared in starting mode. Also, the position of maximum tension and the braking force of take-up are obtained in stopping mode.
A Study on the Manufacturing Cold Forging Dies by Cold Hobbing
Yoo, Heonil ; Kim, Sei-Hwan ; Seo, Hee-Kang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 2, 1996, Pages 594~603
DOI : 10.22634/KSME-A.19220.127.116.114
It has been known that the life time of cold forging dies is shorten by the cracks and wear produced during the operation. Thus it is required to mak the same new one too often, At this time of making new ont the cutting work and electical discharge machining were mormally used. But the precision of product is declined in every times of making the mew dies due to the diffefence in dimensional accuracy arised from the electical discharge machining. Especially it can't meet the delivery date because the production was delayed for making another die. Furthemore it has the problem of increasing the production cost. Therfore inthis study we tried to solve these problems using the hobbing method instead of electical discharge machining.