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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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The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 29, Issue 12 - Dec 2005
Volume 29, Issue 11 - Nov 2005
Volume 29, Issue 10 - Oct 2005
Volume 29, Issue 9 - Sep 2005
Volume 29, Issue 8 - Aug 2005
Volume 29, Issue 7 - Jul 2005
Volume 29, Issue 6 - Jun 2005
Volume 29, Issue 5 - May 2005
Volume 29, Issue 4 - Apr 2005
Volume 29, Issue 3 - Mar 2005
Volume 29, Issue 2 - Feb 2005
Volume 29, Issue 1 - Jan 2005
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Crystal Plasticity Simulation of Ti-6Al-4V Under Fretting Fatigue
Goh Chung Hyun ; Lee Kee Seok ; Ko Jun Bin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 511~517
DOI : 10.3795/KSME-A.2005.29.4.511
Fretting fatigue is often the root cause of the nucleation of cracks at attachments of structural components. Since fretting fatigue damage accumulation occurs over relatively small volumes, the subsurface cyclic plastic strain is expected to be rather non-uniformly distributed in polycrystalline materials. The scale of the cyclic plasticity and the damage process zones is often on the order of microstructure dimensions. Fretting damage analyses using cyclic crystal plasticity constitutive models have the potential to account for the influence of size, morphology, and crystallographic orientation of grains on fretting damage evolution. Two-dimensional plane strain simulations of fretting fatigue are performed using the cyclic properties of Ti-6Al-4V. The crystal plasticity simulations are compared to an initially isotropic
theory with nonlinear kinematic hardening as well as to experiments. The influence of initially isotropic versus textured microstructure in the presence of crystallographic slip is studied.
Derivation of Equivalent Material Properties of Induction Motor Windings Based on Homogenization Method
Bae Jing-Do ; Ko Woo-Sik ; Cho Jin-Rae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 518~525
DOI : 10.3795/KSME-A.2005.29.4.518
The electromagnetic noise generates when natural frequencies of a stator core with wingdings and frame coincide with or approach natural frequencies of the magnetic motive force. In order to suppress such noise, the estimation of natural frequencies of the motor is important at the design stage. However, the natural frequency analysis is not so easy because motor stator is in the laminated plate structure and windings are composed of wires, insulation sheets and vanishs. Thus the accurate prediction of the equivalent material properties of windings becomes an essential task. In this paper, we derive the equivalent material properties using homogenization methods.
Fatigue Life Analysis on Multi-Stacked Film Under Thermal and Residual Stresses
Park Jun-Hyub ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 526~533
DOI : 10.3795/KSME-A.2005.29.4.526
Reliability problem in inkjet printhead, one of MEMS devices, is also very important. To eject an ink drop, the temperature of heater must be high so that ink contacting with surface reaches above
on the instant. Its heater is embedded in the thin multi-layer in which several materials are deposited. MEMS processes are the main sources of residual stresses development. Residual stress is one of the factors reducing the reliability of MEMS devices. We measured residual stresses of single layers that consist of multilayer. FE analysis is performed using design of experiment(DOE). Transient analysis for heat transfer is performed to get a temperature distribution. And then static analysis is performed with the temperature distribution obtained by heat transfer analysis and the measured residual stresses to get a stress distribution in the structure. Although the residual stress is bigger than thermal stress, thermal stress is more influential on fatigue life.
A Relative Nodal Displacement Method for Element Nonlinear Analysis
Kim Wan Goo ; Bae Dae sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 534~539
DOI : 10.3795/KSME-A.2005.29.4.534
Nodal displacements are referred to the initial configuration in the total Lagrangian formulation and to the last converged configuration in the updated Lagrangian furmulation. This research proposes a relative nodal displacement method to represent the position and orientation for a node in truss structures. Since the proposed method measures the relative nodal displacements relative to its adjacent nodal reference frame, they are still small for a truss structure undergoing large deformations for the small size elements. As a consequence, element formulations developed under the small deformation assumption are still valid for structures undergoing large deformations, which significantly simplifies the equations of equilibrium. A structural system is represented by a graph to systematically develop the governing equations of equilibrium for general systems. A node and an element are represented by a node and an edge in graph representation, respectively. Closed loops are opened to form a spanning tree by cutting edges. Two computational sequences are defined in the graph representation. One is the forward path sequence that is used to recover the Cartesian nodal displacements from relative nodal displacement sand traverses a graph from the base node towards the terminal nodes. The other is the backward path sequence that is used to recover the nodal forces in the relative coordinate system from the known nodal forces in the absolute coordinate system and traverses from the terminal nodes towards the base node. One open loop and one closed loop structure undergoing large deformations are analyzed to demonstrate the efficiency and validity of the proposed method.
Control Program for Dexterous Manipulation by Robotic Hand
Hwang Chang-Soon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 540~554
DOI : 10.3795/KSME-A.2005.29.4.540
This paper presents a motion planning and control method for the dexterous manipulation with a robotic hand. For a given trajectory of an object, a simulation system calculates the necessary joint displacements and contact forces at the fingertip surfaces. These joint displacements and contact forces are the reference inputs to the control loops of the robotic fingers. A task is decomposed into a set of primitive motions, and each primitive motion is executed using the planned output of the simulation system as the reference. Force sensors and dynamic tactile sensors are used to adapt to errors and uncertainties encountered during manipulation. Several experimental results are presented.
A Study on the Tensile Property of Ring Specimen Having Gauge Length
Bae Bong-Kook ; Koo Jae-Mean ; Seok Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 555~562
DOI : 10.3795/KSME-A.2005.29.4.555
In this study, we tried to establish the method of evaluating the tensile properties of the ring specimen of Arsene which have gauge length. In this result, we verified the availability of central piece. We made ring specimens and devices such as central piece, pins, and clevises. A proper tensile speed was determined by pre-test. The result of main test was calibrated and compared with the result of FEM. To obtain the tensile properties from the ring test result, we observed two relationships: one is strain-displacement and the other is load ratio-displacement. The tensile properties could be evaluated by using these relationships.
Development of a Finite Element Model for Evaluating Torsional Stiffness of the Frame of a Large Truck
Oh Chae-Youn ; Moon Il-Dong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 563~569
DOI : 10.3795/KSME-A.2005.29.4.563
This paper develops a finite element model of a cabover type large truck. The finite element model is for evaluating torsional stiffness of the frame of the large truck. The torsional test of the frame is conducted in order to validate the developed finite element model. A load cell is used to measure the load applied to the frame. An angle sensor is used to measure the torsional angle. An actuator is used to apply a load to the frame. A vertical upward load and a vertical downward load are applied to the frame in the torsional test. The frame's torsional stiffness is computed with the measured load and torsional angle in the torsional test. The finite element model of the large truck includes cab, deck and payload, suspension, and tire. Cab, deck, and suspension are modeled not to affect the frame's torsional stiffness. The simulation is performed with the developed finite element model for evaluating the frame's torsional stiffness. The simulation results show a very good correlation with the torsional test results in the tendency of changing of the frame's torsional stiffness not only with the direction of the applying load but also with the amount of the applying load. In addition, the simulation results predict the measured torsional stiffness of the frame with about
Complete 3D Surface Reconstruction from Unstructured Point Cloud
Li Rixie ; Kim Seokil ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 570~577
DOI : 10.3795/KSME-A.2005.29.4.570
In this study a complete 3D surface reconstruction method is proposed based on the concept that the vertices of surface model can be completely matched to the unstructured point cloud. In order to generate the initial mesh model from the point cloud, the mesh subdivision of bounding box and shrink-wrapping algorithm are introduced. The control mesh model for well representing the topology of point cloud is derived from the initial mesh model by using the mesh simplification technique based on the original QEM algorithm, and the parametric surface model for approximately representing the geometry of point cloud is derived by applying the local subdivision surface fitting scheme on the control mesh model. And, to reconstruct the complete matching surface model, the insertion of isolated points on the parametric surface model and the mesh optimization are carried out Especially, the fast 3D surface reconstruction is realized by introducing the voxel-based nearest-point search algorithm, and the simulation results reveal the availability of the proposed surface reconstruction method.
Spectral Analysis Method for the Discrete Systems with Initial Conditions
Kim Sunghwan ; Cho Jooyong ; Lee Usik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 578~583
DOI : 10.3795/KSME-A.2005.29.4.578
This paper introduces a fast Fourier transform (FFT)-based spectral dynamic analysis method for the transient responses as well as the steady-state responses of the linear discrete systems subject to non-zero initial conditions. The forced vibration of a viscously damped three-DOF system is considered as the illustrative numerical example. The proposed spectral analysis method is evaluated by comparing its results with the exact analytical solutions and the numerical solutions obtained by the Runge-Kutta method.
The Fretting Fatigue Behavior of Ti-6Al-4V Alloy on Change of Microstructure
Bae Yong Tak ; Choi Sung long ; Kwon Jae Bo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 584~590
DOI : 10.3795/KSME-A.2005.29.4.584
The effect of microstructure on mechanical behavior for Ti-6Al-4V alloy was studied. Two different kinds of specimens are prepared using heat treatments (rolled plate,
in order to Produce different microstructures. Various kinds of mechanical tests such as hardness, tensile, fatigue and fretting fatigue tests are performed for evaluation of mechanical properties with the changes of microstructures. Through these tests, the following conclusions are observed: 1) Microstructures are observed as equiaxed and
microstructures respectively. 2) Impact absorbed energy is superior for the equiaxed microstructure, and the hardness and tensile strength are superior for the
microstructure. 3) The fatigue endurance of
microstritcture shows higher value than that of the equiaxed microstructure. 4) The fatigue endurance in fretting condition was reduced about
from that of the non-fretting condition.
Integrated Design of Servomechanisms Using a Disturbance Observer
Kim Min-Seok ; Chung Sung-Chong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 591~599
DOI : 10.3795/KSME-A.2005.29.4.591
This paper proposes a systematic design methodology for high-speed/high-precision servomechanisms by using a disturbance observer. A multiplicative uncertainty model and a two degree-of-freedom controller composed of a disturbance observer (DOB) and a PD controller are considered as subsystems. Analysis of the system performance, such as internal stability and bandwidth of a servomechanism according to subsystem parameters is conducted for better understanding of the dynamic behavior and interactions among the subsystem parameters. Then, an integrated design methodology, where the interactions are considered simultaneously, is applied to design processes of the servomechanism. The tradeoff relationship between disturbance suppression and measurement noise rejection of the DOB is considered through the design process. Numerical case studies show the improved possibility to evaluate and optimize the dynamic motion performance of the servomechanism. Moreover, the disturbance observer designed based on the proposed design methodology yields excellent disturbance suppression performance.
Evaluation of the Tensile Properties of Fuel Cladding at High Temperatures Using a Ring Specimen
Bae Bong-Kook ; Koo Jae-Mean ; Seok Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 600~605
DOI : 10.3795/KSME-A.2005.29.4.600
In this study, the ring tensile test at high temperature was suggested to evaluate the hoop tensile properties of small tube such as the cladding in the nuclear reactor Using the Arsene's ring model, the ring tensile test was performed and the test data were calibrated. From the result of the ring test with strain gauge and the numerical analysis with 1/8 model, LCRR(load-displacement conversion relationship of ring specimen) was determined. We could obtain the hoop tensile properties by means of applying the LCRR to the calibrated data of the ring tensile test. A few difference was observed in view of the shape of fractured surface and the fracture mechanism between at the high temperature and at the room temperature.
Effect of Wall Thinning on the Failure of Pipes Subjected to Bending Load
Ahn Seok-Hwan ; Nam Ki-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 606~613
DOI : 10.3795/KSME-A.2005.29.4.606
Effects of circumferentially local wall thinning on the fracture behavior of pipes were investigated by monotonic four-point bending. Local wall thinning was machined on the pipes in order to simulate erosion/corrosion metal loss. The configurations of the eroded area included an eroded ratio of d/t= 0.2, 0.5, 0.6, and 0.8, and an eroded length of
25mm, and 120mm. Fracture type could be classified into ovalization, local buckling, and crack initiation depending on the eroded length and eroded ratio. Three-dimensional elasto-plastic analyses were also carried out using the finite element method, which is able to accurately simulate fracture behaviors excepting failure due to cracking. It was possible to predict the crack initiation point by estimating true fracture ductility under multi-axial stress conditions at the center of the thinned area.
Grinding Characteristic Evaluation and Development of Response Surface Models in Surface Grinding Process
Kwak Jae-Seob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 614~623
DOI : 10.3795/KSME-A.2005.29.4.614
This study aims to perform the characteristic evaluation of surface grinding for the STD11 material with experimental and analytic techniques based on the response surface model. The grinding force acting on the workpiece and the ground surface roughness were measured according to the change of grain size, table speed and depth of cut. The effect of spark-out on the grinding force and the surface roughness was also characterized. The frictional coefficient between workpiece and grinding wheel could be determined by the analysis of spark-out effect. From the experimental data, the second-order response surface models were developed to predict the grinding force and the surface roughness. Validation of the developed model was examined.
Dynamic Analysis of a 3-Axis Ultra-Slim Actuator for Optical Disc Drives
Kim Se-Won ; Cho Tae-Min ; Lee Ju-Hyung ; Jin Kyoung-Bog ; Rim Kyung-Hwa ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 624~631
DOI : 10.3795/KSME-A.2005.29.4.624
A note-book PC has become thinner in recent years, which requires the optical disc drives with small height and high memory capacity. Therefore the actuator of optical disc drives must be thinner and have disc tilt compensation function for high density memory. In this paper, the actuator with hybrid type is investigated for 3-axis ultra-slim actuator. A 3-axis ultra-slim actuator is designed by using the modal analysis of the actuator and the electromagnetic analysis of magnetic circuit to achieve dynamic characteristics. Also, magnetic force between tilt magnet and tilt yoke is investigated to and the influence on the DC sensitivity in the focus and track directions.
Surface Lapping Process and Vickers Indentation of Sapphire Wafer for GaN Epitaxy
Shin Gwisu ; Hwang Sungwon ; Kim Keunjoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 4, 2005, Pages 632~638
DOI : 10.3795/KSME-A.2005.29.4.632
The surface lapping process on sapphire wafer was carried out for the epitaxial process of thin film growth of GaN semiconducting material. The planarization of the wafers was investigated by the introduction of the dummy wafers. The diamond lapping process causes the surface deformation of dislocation and micro-cracks. The material deformation due to the mechanical stress was analyzed by the X-ray diffraction and the Vickers indentation. The fracture toughness was increased with the increased annealing temperature indicating the recrystallization at the surface of the sapphire wafer The sudden increase at the temperature of
was correlated with the surface phase transition of sapphire from a