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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 30, Issue 12 - Dec 2006
Volume 30, Issue 11 - Nov 2006
Volume 30, Issue 10 - Oct 2006
Volume 30, Issue 9 - Sep 2006
Volume 30, Issue 8 - Aug 2006
Volume 30, Issue 7 - Jul 2006
Volume 30, Issue 6 - Jun 2006
Volume 30, Issue 5 - May 2006
Volume 30, Issue 4 - Apr 2006
Volume 30, Issue 3 - Mar 2006
Volume 30, Issue 2 - Feb 2006
Volume 30, Issue 1 - Jan 2006
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Improvement of Connection Force in Hydro-Embedding Process Through the Rotational Piercing of the Connection Element
Kim, Bong-Joon ; Kim, Dong-Kyu ; Kim, Dong-Jin ; Moon, Young-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1503~1508
DOI : 10.3795/KSME-A.2006.30.12.1503
To increase the applicability and productivity of hydroforming process, hydro-embedding process was developed by combining the hydro-forming process with embedding process simultaneously. It is necessary in the automotive parts to form hollow bodies with connection elements which combine one part with another. The hydro-embedding process is embedding the connection element hydraulically during the operating steps of the hydroforming. In this study, technique of rotational piercing is added on the existing hydro-embedding to increase the connection force of hydro-embedded element. To estimate the feasibility of new trial process, integrated researches on the hydro-embedding process technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters for various shapes of the connection elements.
Biomechanical Analysis of Lumbar Interspinous Process Fixators and Design of Miniaturization and Advanced Flexibility
Park, Jung-Hong ; Heo, Soon ; Lee, Sung-Jae ; Son, Kwon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1509~1517
DOI : 10.3795/KSME-A.2006.30.12.1509
The intervertebral fusion was reported to increase the degeneration of the neighboring region. Recently, a new technique of inserting an interspinous process fixator has been introduced to minimize the degenerative change in the lumbar spine. This study analyzed biomechanical effects of the fixator in the lumbar spine, and designed a new prototype to improve flexibility of the fixator with a reduced size. The evaluation was based on the displacement, stiffness and von-Mises stress obtained from the mechanical test and finite element analysis. A finite element lumbar model of L1 to L5 was constructed. The finite element model was used to analyze intervertebral fusion, insertion of a commercial fixator and a new prototype. The range of motion of intervertebral segments and pressures at vertebral discs were calculated from FEA. The results showed that the stiffness of the prototype was reduced by 32.9% than that of the commercial one.
3-D Finite Element Modeling of Fiber Reinforced Rubber Composites using a Rubber Element
Jeong, Se-Hwan ; Song, Jung-Han ; Kim, Jin-Woong ; Kim, Jin-Young ; Huh, Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1518~1525
DOI : 10.3795/KSME-A.2006.30.12.1518
Finite element analyses of structures made of the fiber reinforced composites require an adequate method to characterize the high anisotropic behavior induced by one or several layers of fiber cords with different spatial orientation embedded in a rubber matrix. This paper newly proposes a continuum based rebar element considering change of the orientation of the fiber during deformation of the composite. The mechanical behavior of the embedded fiber is modeled using two-node bar elements in order to consider the relative deformation and spatial orientation of the embedded fiber. For improvement of the analysis accuracy, the load-displacement curve of fiber is applied to the stiffness matrix of fiber. A finite element program is constructed based on the total Lagrangian formulation considering both geometric and material nonlinearity. Finite element analyses of the tensile test are carried out in order to evaluate the validity of the proposed method. Analysis results obtained with the proposed method provides realistic representation of the fiber reinforced rubber composite compared to results of other two models by the Halpin-Tsai equation and a rebar element in ABAQUS/Standard.
Degradation of Thermal Creep by Hydrides of Zr-2/5Nb Pressure Tube
Oh, Dong-Joon ; Ma, Young-Wha ; Yoon, Kee-Bong ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1526~1533
DOI : 10.3795/KSME-A.2006.30.12.1526
The aim of this research was to confirm the existence of the thermal creep degradation by hydrides of Zr-2.5Nb pressure tube materials. Small punch creep tests were performed to obtain the relationship between a creep displacement and a loading period at
. A creep stress and a creep strain rate were also converted from the previous results. The creep material constants and the creep stress exponents at the different hydride contents were compared. Finally the hydrides of the axial and circumferential section were observed using OM, SEM and TEM. The following conclusions were made: 1) The degradation of the thermal creep by hydrides was existed and it strongly depended on the hydride contents. 2) As the hydride contents were increased, the creep stress exponents (m) were also increased. 3) Even though the hydride was not precipitated in 50 ppm materials at
, the degradation of thermal creep was found. Therefore, it was believed that this phenomenon strongly related to the hydride precipitation at room temperature.
A Study on the Reliability Evaluation of Shot Peened Aluminium Alloy Using Accelerated Life Test
Nam, Ji-Hun ; Kang, Min-Woo ; Cheong, Seong-Kyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1534~1542
DOI : 10.3795/KSME-A.2006.30.12.1534
In this paper, the concept of accelerated life test, which is a popular research field nowadays, is applied to the shot peened material. To predict the efficient and exact room temperature fatigue characteristics from the high temperature fatigue data, the adequate accelerated model is investigated. Ono type rotary bending fatigue tester and high temperature chamber were used for the experiment. Room temperature fatigue lives were predicted by applying accelerated models and doing reliability evaluation. Room temperature fatigue tests were accomplished to check the effectiveness of predicted data and the adequate accelerated life test models were presented by considering errors. Experimental result using Arrhenius model, fatigue limit obtain almost 5.45% of error, inverse power law has about 1.36% of error, so we found that inverse power law is applied well to temperature-life relative of shot peened material.
Prediction of the Torque Capacity for Tubular Adhesive Joints with Composite Adherends
Oh, Je-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1543~1550
DOI : 10.3795/KSME-A.2006.30.12.1543
Since the performance of joints usually determines the structural efficiency of composite structures, an extensive knowledge of the behavior of adhesive joints and the related effect on joint strength is essential for design purposes. In this study, the torque capacity of adhesive joints was predicted using the combined thermal and mechanical analyses when the adherend was a composite tube. A finite element analysis was performed to evaluate residual thermal stresses developed in the joint, and mechanical s stresses in the adhesive were calculated including both the nonlinear adhesive behavior and the behavior of composite tubes. Three different joint failure modes were considered to predict joint failure: interfacial failure, adhesive bulk failure, and adherend failure. The influence of the composite adherend stacking angle on the residual thermal stresses was investigated, and how the residual thermal stresses affect the joint strength was also discussed. Finally, the predicted results were compared with experimental results available in literature.
Development and Evaluation of ESP Systems for Enhancement of Vehicle Stability during Cornering (II)
Song, Jeong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1551~1556
DOI : 10.3795/KSME-A.2006.30.12.1551
Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a rear wheel steering yaw motion controller (SESP) and an enhanced rear wheel steering yaw motion controller (ESESP). A SESP controls the rear wheels, while an ESESP steers the rear wheels and front outer wheel to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed SESP and ESESP. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the SESP and ESESP are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads.
Finite Element Analysis for Electron Optical System of a Field Emission SEM
Park, Keun ; Park, Man-Jin ; Kim, Dong-Hwan ; Jang, Dong-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1557~1563
DOI : 10.3795/KSME-A.2006.30.12.1557
A scanning electron microscope (SEM) is well known as a measurement and analysis equipment in nano technology, being widely used as a crucial one in measuring objects or analyzing chemical components. It is equipped with an electron optical system that consists of an electron beam source, electromagnetic lenses, and a detector. The present work concerns numerical analysis for the electron optical system so as to facilitate design of each component. Through the numerical analysis, we investigate trajectories of electron beams emitted from a nano-scale field emission tip, and compare the result with that of experimental observations. Effects of various components such as electromagnetic lenses and an aperture are also discussed.
Comparison Study of 2-D OF Parallel Mechanisms: Workspace Optimization and Kinematic Performance
Nam, Yun-Joo ; Lee, Yuk-Hyung ; Park, Myeon-Kwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1564~1572
DOI : 10.3795/KSME-A.2006.30.12.1564
This paper presents the kinematics and workspace optimization of the two different 2-DOF (Degrees-of-Freedom) planar parallel mechanisms: one (called 2-RPR mechanism) with translational actuators and the other (called 2-RRR mechanism) with rotational ones. First of all, the inverse kinematics and Jacobian matrix of each mechanism are derived analytically. Then, the workspace including the output-space and the joint-space is systematically analyzed in order to determine the geometric parameters and the operating range of the actuators. .Finally, the kinematic optimization of the mechanisms is performed with regards to their dexterity, stiffness and space utilization. It is expected that the optimization results can be effectively used as a basic material for the applications of the presented mechanisms to more industrial fields.
Simulation of Extremely Low Cycle Fatigue Fracture in Ductile Cast Iron
Kim, Min-Gun ; Lim, Bok-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1573~1580
DOI : 10.3795/KSME-A.2006.30.12.1573
In this study, fatigue tests were carried out under push-pull loading condition using spheroidal graphite cast iron in order to clarify the internal fatigue fracture mechanism in an extremely low cycle fatigue regime. It is found that a successive observation of internal fatigue damage it is found that the fracture processes go through three stages, that is, the generation, growth and coalescence of microvoids originated from debonding of graphite-matrix interface. It is also found that the crack which is initiated from the void propagates by coalescence of neighboring cracks and the fatigue crack growth rate can be expressed in form of the Manson-Coffin rule type. In this paper, quantitative analyses of fatigue properties for realization of simulation about fatigue life evaluation are also presented.
Reduction of Structure-borne Noises in a Two-Dimensional Cavity using Optimal Treatment of Damping Materials
Lee, Doo-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1581~1587
DOI : 10.3795/KSME-A.2006.30.12.1581
An optimization formulation is proposed to minimize sound pressures in a two-dimensional cavity by controlling the attachment area of viscoelastic unconstrained damping materials. For the analysis of structural- acoustic systems, a hybrid approach that uses finite elements for structures and boundary elements for cavity is adopted. Four-parameter fractional derivative model is used to accurately represent dynamic characteristics of the viscoelastic materials with respect to frequency and temperature. Optimal layouts of the unconstrained damping layer on structural wall of cavity are identified according to temperatures and the amount of damping material by using a numerical search algorithm.
Parametric and Combination Resonances of at Straight Pipe with Pulsatile Flow
Hong, Sung-Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1588~1595
DOI : 10.3795/KSME-A.2006.30.12.1588
The stabilities of a pinned-pinned straight pipe conveying fluid are investigated by complexification-averaging method. The flow is assumed to vary harmonically about a constant mean velocity. Instability conditions of a governing equation are analytically obtained about parametric primary, secondary and combination resonances. The resulted stability conditions show that instabilities exist when the frequency of flow fluctuation is close to one and two times the natural frequency or to the sum of any two natural frequencies. In case that the fluctuated flow frequency is close to the difference of two natural frequencies, instabilities does not exist.
Feasibility Verification of a Non-Contact Vibration Sensor for Rotating Shafts Endowed with Rotational-Encoder Capability
Lee, Ho-Cheol ; Kim, Myong-Ho ; Park, Jung-Yang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1596~1602
DOI : 10.3795/KSME-A.2006.30.12.1596
In this paper, a hybrid sensor is proposed that has two capabilities: the first is to sense longitudinal or flexural transient vibration signals selectively which are transmitted along the target shaft, and the second to measure the rotating speed of the shaft. All measurements are made in a non-contact manner since this sensor uses magnetostriction as its measuring principle. The signal selection between two vibration modes requires only electrical switching operations and the switching between these two sensing capabilities-vibrations and rotational speed-are accomplished by a very simple mechanical operation. To verify the capabilities of the proposed sensor, a prototype sensor is fabricated and the experiments are made. The results show this sensor can embody two sensing capabilities in one sensor configuration.
Compression Characteristics and Energy Absorption of Composite Egg-Box Panels
Chung, Jee-Gyu ; Chang, Seung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1603~1610
DOI : 10.3795/KSME-A.2006.30.12.1603
In this paper compressive characteristics of composite egg-box panels were investigated and energy absorption was calculated from the nominal stress-strain relations obtained by the compressive tests. Several different stacking sequences and number of plies were introduced for investigation of static compression characteristics and the energy absorption rates of composite egg-box panels. The compressive stress-strain relation and energy absorption of various composite egg-box panels were compared with those of aluminium egg-box panels. From the test results it was found that the fracture behavior of composite egg-box panel was affected by stacking angle causing different local deformation, during lay-up and draping processes and types of prepreg; that is, plain weave carbon/epoxy and 4-harness satin glass/epoxy. The energy absorption capacity of composite egg-box panels were proved to be higher than that of aluminium egg-box panels with low mass.
Atomic Force Microscope for Standard Length Metrology
Lee, Dong-Yeon ; Kim, Dong-Min ; Gweon, Dae-Gab ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1611~1617
DOI : 10.3795/KSME-A.2006.30.12.1611
A compact and two-dimensional atomic force microscope (AFM) using an orthogonal sample scanner, a calibrated homodyne laser interferometer and a commercial AFM head was developed for use in the nano-metrology field. The x and y position of the sample with respect to the tip are acquired by using the laser interferometer in the open-loop state, when each z data point of the AFM head is taken. The sample scanner which has a motion amplifying mechanism was designed to move a sample up to
in orthogonal way, which means less crosstalk between axes. Moreover, the rotational errors between axes are measured to ensure the accuracy of the calibrated AFM within the full scanning range. The conventional homodyne laser interferometer was used to measure the x and y displacements of the sample and compensated via an X-ray interferometer to reduce the nonlinearity of the optical interferometer. The repeatability of the calibrated AFM was measured to sub-nm within a few hundred nm scanning range.
Structural Integrity Evaluation of SG Tube with Surface Wear-type Defects
Kim, Jong-Min ; Huh, Nam-Su ; Chang, Yoon-Suk ; Hwang, Seong-Sik ; Kim, Joung-Soo ; Kim, Young-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1618~1625
DOI : 10.3795/KSME-A.2006.30.12.1618
During the last two decades, several guidelines have been developed and used for assessing the integrity of a defective steam generator (SG) tube that is generally caused by stress corrosion cracking or wall-thinning phenomenon. However, as some of SG tubes are also failed due to fretting and so on, alternative failure estimation schemes are required for relevant defects. In this paper, parametric three-dimensional finite element (FE) analyses are carried out under internal pressure condition to simulate the failure behavior of SG tubes with different defect configurations; elliptical wear, tapered and flat wear type defects. Maximum pressures based on material strengths are obtained from more than a hundred FE results to predict the failure of SG tube. After investigating the effect of key parameters such as defect depth, defect length and wrap angle, simplified failure estimation equations are proposed in relation to the equivalent stress at the deepest point in wear region. Comparison of failure pressures predicted by the proposed estimation scheme with corresponding burst test data showed a good agreement.
An Improved Finite Element Method by Adding Arbitrary Nodes in a Domain
Kim, Hyun-Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1626~1633
DOI : 10.3795/KSME-A.2006.30.12.1626
In the present paper, in the context of the meshless interpolation of a moving least squares (MLS) type, a novel method which uses primary and secondary nodes in the domain and on the global boundary is introduced, in order to improve the accuracy of solution. The secondary nodes can be placed at any location where one needs to obtain a better resolution. The support domains for the shape functions in the MLS approximation are defined from the primary nodes, and the secondary nodes use the same support domains. The shape functions based on the MLS approximation, in an integration domain, have a single type of a rational function, which reduces the difficulty of numerical integration to evaluate the weak form. The present method is very useful in an adaptive calculation, because the secondary nodes can be easily added and moved without an additional mesh. Several numerical examples are presented to illustrate the effectiveness of the present method.
Structural and Thermal Sensitivity Analysis of a High-Precision Centerless Grinding Machine for Machining Ferrules
Kim, Seok-Il ; Lee, Won-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1634~1641
DOI : 10.3795/KSME-A.2006.30.12.1634
High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a sensitivity analysis for structural and thermal characteristics was carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW table feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The results of the structural sensitivity analysis illustrated that the vertical stiffness of hydrostatic guideway for the RW table feed system greatly influenced the horizontal loop stiffness, and the results of the thermal sensitivity analysis illustrated that the heat generation rates at hydrostatic bearings and belt pulley greatly influenced the temperature rise of hydrostatic bearings and the deviation of thermal displacement between GW and RW.
A Micro Mixer with Recirculation Zones
Lee, Jong-Kwang ; Kim, Young-Dae ; Choe, Jae-Hoon ; Kwon, Se-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1642~1648
DOI : 10.3795/KSME-A.2006.30.12.1642
This paper describes enhancement of the mixing efficiency of a multilamination micro mixer by adding a number of recirculation zones downstream of the mixing zone. Numerical simulation was employed to estimate the mixing efficiency and the pressure drop under various conditions. Numerical results indicated that recirculation micro mixer brought about not only the increase of the mixing efficiency but also the decrease of the pressure drop. Micro mixers were fabricated using photosensitive glass by anisotropic wet etching technique. The width and height of the micro channel were
, respectively. The performance of micro mixer was measured using color intensity variation of the fluid. Except for extremely low Re below 40, the recirculation micro mixer of the present study showed improved mixing. And the enhancement of the mixing increased as Re rose. When Re increased beyond 400, more than 90% of the mixing was observed in the experiment.
Development of a Fizeau Interferometer System for Measuring the Profile of Large Optical Lens
Bae, Kwang-Hwan ; Lee, Eung-Suk ; Lee, Ki-Am ; Kim, Ok-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 30, issue 12, 2006, Pages 1649~1657
DOI : 10.3795/KSME-A.2006.30.12.1649
Fizeau interferometer is well known optical instrument for measuring the lens profile accurately. The object of this study is focused on the design and optical measuring techniques for large optical components, such as a reflection mirror for astronomical purpose. Measuring of large optical lens, the object could not be moved as small one but the measuring instrument must be moved for the alignment, because of the geometric conditions and the accuracy of the stage. Therefore, a five axis stage is designed to align the Interferometer instead of the measuring object. This instrument will be used for an on machine measuring system in polishing machine for large optical lens.