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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 28, Issue 12 - Dec 2004
Volume 28, Issue 11 - Nov 2004
Volume 28, Issue 10 - Oct 2004
Volume 28, Issue 9 - Sep 2004
Volume 28, Issue 8 - Aug 2004
Volume 28, Issue 7 - Jul 2004
Volume 28, Issue 6 - Jun 2004
Volume 28, Issue 5 - May 2004
Volume 28, Issue 4 - Apr 2004
Volume 28, Issue 3 - Mar 2004
Volume 28, Issue 2 - Feb 2004
Volume 28, Issue 1 - Jan 2004
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A Study on the Measurement System Design for the Resin Flow and Curing in the Vacuum Assisted Resin Transfer Molding(VARTM) Process Using the Long Period Fiber Bragg Grating
Yoon, Young-Ki ; Chung, Seung-Hwan ; Lee, Woo-Il ; Lee, Byoung-Ho ; Byun, Joon-Hyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 489~494
DOI : 10.3795/KSME-A.2004.28.5.489
Long Period Gratings (LPG) is currently receiving considerable attention because of their consistent measuring results fur pressure, temperature, strain and flow. LPG is easier to prepare and has a high sensitivity compared with Fiber Bragg Gratings (FBG). In addition, this kind of optical fiber sensors could be used for implementations in various structures. In this paper, LPG was used to monitor in situ the resin flow and the curing process in VARTM (Vacuum Assisted Resin Transfer. Molding). In order to demonstrate the effectiveness of the method, FBG is inserted into the glass mat to monitor the resin flow using optical spectrum analyzer (OSA). The curing reactions in VARTM are also observed using the same method. From the results, the attenuation wavelength shift and the loss change of attenuation band can be obtained from the status of the RTM (Resin Transfer Molding) sample owing to the internal variations of the .effective index, temperature, and pressure. It is shown that the proposed LPG is more effective in monitoring the curing reaction than FBG.
The 6-DOF Parallel Manipulator Having the Specific Trajectory Based on the Kinematic Isotropy
Yang, Hyun-Ik ; Xu, Yuan-Ge ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 495~502
DOI : 10.3795/KSME-A.2004.28.5.495
In this paper, kinematic structure of parallel manipulator having 6-DOF is determined to follow the specific trajectory represented by several curves expressed by the parametric variable functions. In addition, the parallel manipulator is designed to have a high dexterity by considering a kinematic isotropy which can stabilize the motion of the moving platform in the restricted workspace.
Design of the Well-Conditioned Observer - A Linear Matrix Inequality Approach -
Jung, Jong-Chul ; Huh, Kun-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 503~510
DOI : 10.3795/KSME-A.2004.28.5.503
In this paper, the well-conditioned observer for a stochastic system is designed so that the observer is less sensitive to the ill-conditioning factors in transient and steady-state observer performance. These factors include not only deterministic uncertainties such as unknown initial estimation error, round-off error, modeling error and sensing bias, but also stochastic uncertainties such as disturbance and sensor noise. In deterministic perspectives, a small value in the L
norm condition number of the observer eigenvector matrix guarantees robust estimation performance to the deterministic uncertainties. In stochastic viewpoints, the estimation variance represents the robustness to the stochastic uncertainties and its upper bound can be minimized by reducing the observer gain and increasing the decay rate. Both deterministic and stochastic issues are considered as a weighted sum with a LMI (Linear Matrix Inequality) formulation. The gain in the well-conditioned observer is optimally chosen by the optimization technique. Simulation examples are given to evaluate the estimation performance of the proposed observer.
Effects of Gravity and Angular Velocity Profiles on the Dynamic Behavior of an Automatic Ball Balancer
Jung, Du-Han ; Chung, Jin-Tai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 511~516
DOI : 10.3795/KSME-A.2004.28.5.511
The dynamic behavior of an automatic ball balancer (ABB) is studied considering the effects of gravity and angular velocity profiles. In this study, a physical model for an ABB installed on the Jeffcott rotor is adopted in order to investigate the effects of gravity and angular acceleration. The equations of motion for the rotor with ABB are derived by using Lagrange`s equation. Based on derived equations, dynamic responses for the rotor are computed by using the generalized-o method. From the computed responses, the effects of gravity and angular velocity profiles on the dynamic behavior are investigated. It is found that the balancing of the rotor with ABB can be achieved regardless of gravity. It Is also shown that a smooth velocity profile yields relatively smaller vibration amplitude than a non-smooth velocity profile.
Estimation of Tire Braking Force and Road Friction Coefficient Between Tire and Road Surface For Wheel Slip Control
Hong, Dae-Gun ; Huh, Kun-Soo ; Yoon, Pal-Joo ; Hwang, In-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 517~523
DOI : 10.3795/KSME-A.2004.28.5.517
Recently, wheel slip controllers with controlling the wheel slip directly has been studied using the brake-by-wire actuator. The wheel slip controller is able to control the braking force more accurately and can be adapted to various different vehicles more easily than the conventional ABS systems. The wheel slip controller requires the information about the tire braking force and road condition in order to achieve the control performance. In this paper, the tire braking forces are estimated considering the variation of the friction between brake pad and disk due to aging of the brake, moisture on the contact area or heating. In addition, the road friction coefficient is estimated without using tire models. The estimated performance of tire braking forces and the road friction coefficient is evaluated in simulations.
Effect of Reference Loads on Fracture Mechanics Analysis of Surface Cracked Pipe Based on Reference Stress Method
Shim, Do-Jun ; Son, Beom-Goo ; Kim, Yun-Jae ; Kim, Young-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 524~531
DOI : 10.3795/KSME-A.2004.28.5.524
To investigate relevance of the definition of the reference stress to estimate J and
for surface crack problems, this paper compares FE J and
results for surface cracked pipes with those estimated according to the reference stress approach using various definitions of the reference stress. Pipes with part circumferential inner surface crack and finite internal axial crack are considered, subject to internal pressure and global bending. The crack depth and aspect ratio are systematically varied. The reference stress is defined in four different ways using (i) the local limit load, (ii) the global limit load, (iii) the global limit load determined from the FE limit analysis, and (iv) the optimized reference load. It is found that the reference stress based on the local limit load gives overall excessively conservative estimates of J and
. Use of the global limit load clearly reduces the conservatism, compared to that of the local limit load, although it can provide sometimes non-conservative estimates of J and
. The use of the FE global limit load gives overall non-conservative estimates of J and
. The reference stress based on the optimised reference load gives overall accurate estimates of J and
, compared to other definitions of the reference stress. Based on the present finding, general guidance on the choice of the reference stress for surface crack problems is given.
Evaluation of the Residual Stress with Respect to Supporting Type of Multi-layer Thin Film for the Metallization of Pressure Sensor
Shim, Jae-Joon ; Han, Geun-Jo ; Han, Dong-Seup ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 532~538
DOI : 10.3795/KSME-A.2004.28.5.532
MEMS technology applying to the sensors and micro-electro devices is complete system. These microsystems are made by variable processes. Especially, the mentallization process has very important functions to transfer the power operating the sensor and signal induced from sensor part. But in the structures of MEMS the local stress concentration and deformation are often yielded by an irregular geometrical shape and different constraint. Therefore, this paper studies the effect of supporting type and thickness ratio about thin film of the substrate on the residual stress variation when the thermal loads is applied to the multi-layer thin film fabricated by metallization process. Specimens were made from several materials such as Al, Au and Cu. Then, uniform thermal load was applied, repeatedly. The residual stress was measured by FE Analysis and nano-indentation method using AFM. Generally, the specimen made of Al induced the larger residual stress than that of made of other materials. Specimen made of Cu and Au having the low thermal expansion coefficient induces the minimum residual stress. Similarly, the lowest indentation length was measured by nano-indentation method in the Si/Au/Cu specimen. Particularly, clusters are created in the specimen made of Cu by thermal load and the indentation length became increasingly large by cluster formation.
A Revolute Robot Manipulator with a New Structure
Choi, Hyung-Sik ; Kim, Young-Sik ; Baek, Chang-Yul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 539~546
DOI : 10.3795/KSME-A.2004.28.5.539
Conventional robot manipulators actuated by motors with the speed reducer such as the harmonic drive have weakness in the load capacity, since the speed reducer does not have enough strength. To overcome this, a new type of the robot actuator based on the four-bar-link mechanism driven by the ball screw was proposed and constructed. Also, a new type of a revolute-jointed robot manipulator composed of the developed actuators was developed. The base axis is actuated by the motor with the conventional speed reducer, but the other axes are actuated by the proposed actuators. The kinematics and dynamics of the robot were analyzed, and the performance test of the robot was made. Through the test results, the performance of superior load capacity versus the robot weight is shown.
Molecular Dynamics Simulation of Adhesive Friction of Silicon Asperity
Park, Seung-Ho ; Cho, Sung-San ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 547~553
DOI : 10.3795/KSME-A.2004.28.5.547
A hemispherical asperity moving over a flat plane is simulated based on classical molecular dynamics. The asperity and the plane consist of silicon atoms whose interactions are governed by the Tersoff three-body potential. The gap between the asperity and the plane is maintained to produce attractive normal force in order to investigate the adhesive friction and wear. The simulation focuses on the influence of crystallographic orientation of the contacting surfaces and the moving direction. It is demonstrated that the adhesive friction and wear are lower when crystallographic orientations of the contacting surfaces are different, and also depend on the moving direction relative to the crystal1ographic orientation.
Empirical Relationship Between SP-curves and Tensile Properties in Mn-Mo-Ni Low Alloy Steels
Lee, Jae-Bong ; Kim, Min-Chul ; Park, Jai-Hak ; Lee, Bong-Sang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 554~562
DOI : 10.3795/KSME-A.2004.28.5.554
An empirical relationship between parameters from SP curves and tensile properties has been systematically investigated by experimental tests and FEM simulations. A series of SP and tensile tests were performed. SP tests were also simulated by FE analysis with various tensile properties. It was found that the yield loads(Py) and the maximum loads(
) in SP curves were linearly related with the yield strength(
) and the tensile strength(
), respectively. The yield loads defined from the intersection point of two lines tangent to the elastic bending region and plastic bending region showed better relation to the yield strength than those from offset line. The maximum loads in SP curves showing plastic instability region was linearly related with the tensile strengths. The slope of SP curves in simulation results had a close correlation with the hardening coefficient and hardening strength as well.l.l.l.
Effective Strength Estimation of Damaged Materials Based on Two-Dimensional Mesoscopic Analysis
Lee, Jeoung-Gwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 563~570
DOI : 10.3795/KSME-A.2004.28.5.563
Two-dimensional mesoscopic analysis (meso-analysis) is applied to solids including microdefects such as microcracks or holes. For the problem of effective moduli of microdefrcted solids, various approximate schemes are introduced by using microcrack density and hole density for macro level parameter. Also, microcracks distributed in the parallel direction and random direction are considered. Several numerical studies using meso-analysis are carried out and the results are compared with several approximate schemes in order to show the validity of proposed meso-analysis.
The Study of Impact Analysis of TFT-LCD Module
Lee, Jeoung-Gwen ; Choi, Sung-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 571~577
DOI : 10.3795/KSME-A.2004.28.5.571
The impact behavior of TFT-LCD module is very complicated because the module is assisted with three parts such as back light unit, LCD Panel and top chassis. Especially, the back light unit is constructed with several small and thin parts made by plastics or steels. The design of the back light unit is very important because the recent demand is more lighter, thinner and narrower module. The aim of the present study is the investigation of mechanical characteristics during impact loading. The back light unit must assist TFT-LCD Panel made by glass and guide qualification of handling environment. This paper focus on the dynamic behavior of module and carries out a series of computer simulation using LS-DYNA program. Comparing with test results previously performed, dynamic characteristics of TFT-LCD module are estimated
Determination of Brinell Hardness through Instrumented Indentation Test without Observation of Residual Indent
Kim, Sung-Hoon ; Choi, Yeol ; Kwon, Dong-Il ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 578~585
DOI : 10.3795/KSME-A.2004.28.5.578
Hardness test is performed for determination of the other properties, such as strength, wear resistance and deformation resistance, as well as hardness itself. And it is performed for prediction of residual lifetime by analysis of hardness reduction or hardness ratio. However, hardness test has limitation that observation of residual indent is needed for determination of hardness value, and that is the reason for not to be widely used in industrial field. Therefore, in this study, we performed researches to obtain Brinell hardness value from quantitative numerical formula by analysing relationship between indentation depths from indentation load-depth curve and mechanical properties such as work hardening exponent, yield strength and elastic modulus.
A Study on the Failure Analysis and Performance Improvement of a Decanter
Shin, Chang-Ho ; Lee, Dong-Chul ; Kim, Woo-Hyung ; Choi, Tae-Ju ; Chung, Jin-Tai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 586~592
DOI : 10.3795/KSME-A.2004.28.5.586
In this study, the failure analysis of a decanter is carried out and the methods of performance improvement are presented. The decanter is a centrifugal separator that is used to separate water and solids from municipal and industrial sludge. Therefore, the decanter should be designed to improve the dewatering of sludge. Besides high performance, the decanter should guarantee its life time under a severe using condition. For theses reasons, the failure analysis and performance improvement of the decanter are studied. It is found from this study that the failure is caused by mass unbalance, wear, clogging or crack. If these failure causes are prevented, the life time as well as the performance is expected to be improved.
Study of Design and Verification for Control Rod Control System
Yook, Sim-Kyun ; Lee, Sang-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 593~602
DOI : 10.3795/KSME-A.2004.28.5.593
We have developed a digital control rod control system not only to improve its performance but also to improve its reliability and speed of response so that it can replace the old fashioned analog system. However, a new developed digital control system should be tested to prove the validity by using any prototype or mock-up before application. The reliability prediction and the reliability block diagram analysis methods were adopted to verify the reliability of the developed hardware. For the case of software, especially fur a new developed control algorithm it has been tested to prove performances and validation by using a dynamic simulator and mock-up of control rod drive mechanism altogether. Here we want to present some key factors regarding to the new developed digital system with some verification procedures.
Motion Control of a Pneumatic Servo XY-Plotter using Neural Network
Hwang, Un-Kyoo ; Cho, Seung-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 603~609
DOI : 10.3795/KSME-A.2004.28.5.603
This paper deals with the issue of Neural Network-based control for a rodless pneumatic cylinder system which is utilized for a pneumatic XY-plotter. In order to identify the system design parameters, the open loop response of a pneumatic rodless cylinder controlled by a pneumatic servovalve is investigated by applying a self-excited oscillation method. Based on the system design parameters, the PD feedback compensator is designed and then Neural Network is incorporated with it. The experiment of a trajectory tracking control using a PD-NN has been performed and proved its excellent performance by comparing with that of a PD feedback compensator.
Effect of Hydride of the PHWR Pressure Tube on the LBB Evaluation
Oh, Dong-Joon ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 610~616
DOI : 10.3795/KSME-A.2004.28.5.610
The aim of this study was to investigate the hydride embrittlement when the LBB evaluation was carried out for the integrity of PHWR Pressure Tubes. The transverse tensile and CCT toughness tests were performed at three hydrogen concentrations while the test temperatures were changed (RT to 30
). Both the transverse tensile and the fracture toughness tests showed the hydrogen embitterment clearly at RT but this phenomenon was disappeared while the test temperature arrived at 25
. Using the DHC test results, the CCL and LBB time were calculated and compared. The hydride embrittlement at the LBB evaluation made the LBB time short definedly. If the operating temperature, DHCV and LBB deterministic parameters such as A and m were known, LBB time could be estimated without the calculation of CCL.
A Dynamic Thermal Modeling of Chemical Mechanical Polishing Process
Seok, Jong-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 617~623
DOI : 10.3795/KSME-A.2004.28.5.617
This paper describes a dynamic thermal model for a representative dual axis rotational Chemical-Mechanical Polishing (CMP) tool. The model is one-dimensional but configured in the two-dimensional space and consists of three sub-models (pad, wafer and slurry fluid), with the first and the second that are time-dependent heat conduction-convection models with linear stationary (wafer) and nonlinear moving (pad) boundary conditions, and the last one that is a heat transport-convection model (slurry fluid). The modeling approach is validated by comparing the simulation results with available experimental data.
Fabrication of Real 3D Shape Components Using Bi-Sn Alloys
Chung, Sung-Il ; Park, Sun-Joon ; Im, Yong-Gwan ; Choi, Jae-Young ; Jeong, Hae-Do ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 624~631
DOI : 10.3795/KSME-A.2004.28.5.624
In this paper, new replication techniques fur a metal microcomponent having a real 3D shape were introduced. Helical gear was selected as one of a real 3D microcomponents for this study. The helical gear, which was made of photo-curable resin, was fabricated as a master pattern by microstereolithography technology. Then, a silicone rubber mold was fabricated from the master pattern. Lastly, a final bismuth alloy pattern was transferred from the silicone rubber mold by the microcasting process. In this paper, the replication technique is described in detail from the master pattern to the final pattern with some investigation on factors related to the technique.
A Study on Inverse Problem of Materials Forming Process using Optimization Technique and Distributed Computing
Choi, Joo-Ho ; Oh, Dong-Gil ; Ha, Duk-Sik ; Kim, Jun-Bum ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 632~639
DOI : 10.3795/KSME-A.2004.28.5.632
In this paper, an inverse problem of glass forming process is studied to determine a number of unknown heat transfer coefficients which are imposed as boundary conditions. An analysis program for transient heat conduction of axi-symmetric dimension is developed to simulate the forming and cooling process. The analysis is repeated until it attains periodic state, which requires at least 30 cycles of iteration. Measurements are made for the temperatures at several available time and positions of glass and moulds in operation. Heat removal by the cooling water from the plunger is also recorded. An optimization problem is formulated to determine heat transfer coefficients which minimize the difference between the measured data and analysis results. Significant time savings are achieved in finite difference based sensitivity computation during the optimization by employing distributed computing technique. The analysis results by the optimum heat transfer coefficients are found to agree well with the measured data.
A Study on the Measurement of the Crack Length Using the DCPD Method for the Fracture Test of the Pipe Specimen
Park, Jae-Sil ; Seok, Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 640~647
DOI : 10.3795/KSME-A.2004.28.5.640
In order to perform elastic-plastic fracture mechanical analyses, fracture resistance curves for concerned materials are required. The unloading compliance method and the DCPD(Direct Current Potential Drop) method have been widely used for measuring the crack length and the extension for a standard specimen fracture resistance curve test. However it is difficult to apply the unloading compliance method to a real pipe fracture resistance curve test. The objective of this paper is to propose the calibration equation between the normalized crack length and the normalized electric potential, and to apply to pipe fracture experiments. For these, finite element analyses were performed with various current input locations and crack front configurations. Also the 4-point bending jig was manufactured for a pipe test and the DCPD method was used to measure crack extensions and crack lengths for a pipe test. The calculated crack length by the DCPD method agreed with the measured crack length within 5% error.
Product Information Extraction System Based on STEP in CPC Environment
Park, Sang-Ho ; Keem, Joon-Hyoung ; Kim, Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 648~653
DOI : 10.3795/KSME-A.2004.28.5.648
Collaborative product commerce (CPC) supports a collaboration that a global enterprise and customer related to lift cycle of product share product information and a collaboration process for the collaboration, and integrating applications. In this paper, we use common data schema in order to solve a interoperability problem about shared product information between enterprises. And we map to common data schema from each other different data format. Therefore we implement CPC Adaptor in order to integrate distributed product information.
Combined Process of Ironing and Redrawing in Progressive Drawing
Chung, Joon-Ki ; Cho, Woong-Shick ; Lee, Taek-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 28, issue 5, 2004, Pages 654~661
DOI : 10.3795/KSME-A.2004.28.5.654
In deep drawing of sheet metal, there are many cases in which the uniform and thin wall thickness of the drawn products is more important than the bottom thickness. In this case, we can not easily get the deep drawn products with the uniform and precise wall thickness by only drawing process. Therefore in general the manufacturing processes which both the drawing and the ironing process are proceeded sequentially are used. But this method has the disadvantages of a cost-up, decrease of productivity and degradation of quality, because the ironing process is added after the drawing process. In this study, in order to improve those problems and to enhance the effect of deep drawing, the combined process of redrawing and ironing fur multistep drawing of cylindrical cups is used. In this experiment, we considered the characteristics of the combined process such as the relation between the drawing and ironing rates, the drawing limits and the forces needed for operations. The suggested force prediction shows that it can successfully represent experimental results.