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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 38, Issue 12 - Dec 2014
Volume 38, Issue 11 - Nov 2014
Volume 38, Issue 10 - Oct 2014
Volume 38, Issue 9 - Sep 2014
Volume 38, Issue 8 - Aug 2014
Volume 38, Issue 7 - Jul 2014
Volume 38, Issue 6 - Jun 2014
Volume 38, Issue 5 - May 2014
Volume 38, Issue 4 - Apr 2014
Volume 38, Issue 3 - Mar 2014
Volume 38, Issue 2 - Feb 2014
Volume 38, Issue 1 - Jan 2014
Selecting the target year
Wear Properties of Nuclear Graphite IG-110 at Elevated Temperature
Wei, Dunkun ; Kim, Jaehoon ; Kim, Yeonwook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 469~474
DOI : 10.3795/KSME-A.2014.38.5.469
The high temperature gas-cooled reactor (HTR-10) is designed to produce electricity and hydrogen. Graphite is used as reflector, support structures, and a moderator in reactor core; it has good resistance to neutron and is a suitable material at high temperatures. Friction is generated in the graphite structures for the core reflector, support structures, and moderator because of vibration from the HTR-10 fuel cycle flow. In this study, the wear characteristics of the isotropic graphite IG-110 used in HTR-10 were evaluated. The reciprocating wear test was carried out for graphite against graphite. The effects of changes in the contact load and sliding speeds at room temperature and
on the coefficient of friction and specific wear rate were evaluated. The wear behavior of graphite IG-110 was evaluated based on the wear surfaces.
Inducement of Design Parameters for Reliability Improvement of Servo Actuator for Hydraulic Valve Operation
Sung, Baek Ju ; Kim, Do Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 475~482
DOI : 10.3795/KSME-A.2014.38.5.475
The precision hydraulic valve is widely used in various industrial field like aircraft, automobile, and general machinery. Servo actuator is the most important device for driving the precise hydraulic valve. The reliable operation of servo actuator effects on the overall hydraulic system. The performance of servo actuator relies on frequency response and step response according to arbitrary input signal. In this paper, we performed the analysis for the components of servo actuator to satisfy the reliable operation and response characteristics through the reliability analysis, and also induced the design parameters to realize the reliable operation and fast response characteristics of servo actuator for hydraulic valve operation through the empirical knowledge of experts and electromagnetic theories. We suggested the design equations to determine the values of design parameters of servo actuator as like bobbin size, length of yoke and plunger and turn number of coil, and verified the achieved design values through FEM analysis and performance tests using some prototypes of servo actuators adapted in hydraulic valve.
Characteristics of Shear Strength for joined SiC-SiC Ceramics
Yoon, Han Ki ; Jung, Hun Chea ; Hinoki, T. ; Kohyama, A. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 483~487
DOI : 10.3795/KSME-A.2014.38.5.483
In this study, joining methods with SiC powder as the joining adhesives were studied in order to avoid the residual stresses coming from CTE (Coefficient of Thermal Expansion) mismatch between substrate and joining layer. The shear strength and microstructure of joined material between SiC substrates are investigated. The commercial Hexoloy-SA (Saint-Gobain Ceramics, USA) used in this work as substrate material. The fine
-SiC nano-powder which the average particle size is below 30 nm,
were used as joining adhesives. The specimens were joined with 20MPa and
by hot pressing in argon atmosphere. The shear test was performed to investigate the bonding strength. The cross-section of the joint was characterized by using an optical microscope and scanning electron microscopy (SEM).
Development of Optimization Algorithm Using Sequential Design of Experiments and Micro-Genetic Algorithm
Lee, Jung Hwan ; Suh, Myung Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 489~495
DOI : 10.3795/KSME-A.2014.38.5.489
A micro-genetic algorithm (MGA) is one of the improved forms of a genetic algorithm. It is used to reduce the number of iterations and the computing resources required by using small populations. The efficiency of MGAs has been proved through many problems, especially problems with 3-5 design variables. This study proposes an optimization algorithm based on the sequential design of experiments (SDOE) and an MGA. In a previous study, the authors used the SDOE technique to reduce trial-and-error in the conventional approximate optimization method by using the statistical design of experiments (DOE) and response surface method (RSM) systematically. The proposed algorithm has been applied to various mathematical examples and a structural problem.
Open Source-Based Surgical Navigation for Fracture Reduction of Lower Limb
Joung, Sanghyun ; Park, Jaeyeong ; Park, Chul-Woo ; Oh, Chang-Wug ; Park, Il Hyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 497~503
DOI : 10.3795/KSME-A.2014.38.5.497
Minimally invasive intramedullary nail insertion or plate osteosynthesis has shown good results for the treatment of long bone fractures. However, directly seeing the fracture site is impossible; surgeons can only confirm bone fragments through a fluoroscopic imaging system. The narrow field of view of the equipment causes malalignment of the fracture reduction, and radiation exposure to medical staff is inevitable. This paper suggests two methods to solve these problems: surgical navigation using 3D models reconstructed from computed tomography (CT) images to show the real positions of bone fragments and estimating the rotational angle of proximal bone fragments from 2D fluoroscopic images. The suggested methods were implemented using open-source code or software and evaluated using a model bone. The registration error was about 2 mm with surgical navigation, and the rotation estimation software could discern differences of
within a range of
through a comparison with the image of a normal bone.
Accelerated Life Prediction of Ethylene-Propylene Diene Monomer Rubber Subjected to Combined Degradation
Han, Seung Wook ; Kwak, Seung Bum ; Choi, Nak Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 505~511
DOI : 10.3795/KSME-A.2014.38.5.505
The EPDM(ethylene-propylene diene monomer) rubbers used for manufacturing engine radiator hoses can be degraded by locally generated electrical stress in addition to thermal and mechanical stresses. This study presents an accelerated life prediction of the EPDM rubber under electrochemical stresses using the Arrhenius formula under various aging temperatures(
). The modified life prediction formula considers the relationship between the gradient(
) and the Arrhenius constant(C). The effects of tensile strain(5%, 10%) on the life of these rubbers were investigated. The aging temperature influences EPDM rubber life, and tensile strain was predicted. It was confirmed that the modified life prediction was within the data deviation level of the test.
CFD-based Thrust Analysis of Unmanned Aerial Vehicle in Hover Mode: Effects of Single Rotor Blade Shape
Yun, Jae Hyun ; Choi, Ha-Young ; Lee, Jongsoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 513~520
DOI : 10.3795/KSME-A.2014.38.5.513
An unmanned aerial vehicle (UAV) should be designed to be as small and lightweight as possible to optimize the efficiency of changing the blade shape to enhance the aerodynamic performance, such as the thrust and power. In this study, a computational fluid dynamics (CFD) simulation of an unmanned multi-rotor aerial vehicle in hover mode was performed to explore the thrust performance in terms of the blade rotational speed and blade shape parameters (i.e., taper ratio and twist angle). The commercial ADINA-CFD program was used to generate the CFD data, and the results were compared with those obtained from blade element theory (BET). The results showed that changes in the blade shape clearly affect the aerodynamic thrust of a UAV rotor blade.
Fracture Behavior of Adhesive-Bonded Aluminum Foam with Double Cantilever Beam
Bang, Hye-Jin ; Lee, Sang-Kyo ; Cho, Chongdu ; Cho, Jae-Ung ; Choi, Hae-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 521~526
DOI : 10.3795/KSME-A.2014.38.5.521
In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus.
Image-Based Computational Modeling of Porous Matrix Composites and Calculation of Poroelastic Coefficients
Kim, Sung Jun ; Shin, Eui Sup ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 527~534
DOI : 10.3795/KSME-A.2014.38.5.527
Poroelastic analyses of fiber-reinforced composites were performed using image-based computational models. The section image of a porous matrix was analyzed in order to investigate the porosity, number of pores, and distribution of pores. The resolution, location, and size of the section image were considered to quantify the effective elastic modulus, poroelastic parameter, and strain energy density using the image-based computational models. The poroelastic parameter was calculated from the effective elastic modulus and pore pressure-induced strain. In addition, the results of the poroelastic analyses were verified through representative volume elements by simplifying various pore configurations and arrangements.
Robust Optimization Using Supremum of the Objective Function for Nonlinear Programming Problems
Lee, Se Jung ; Park, Gyung Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 535~543
DOI : 10.3795/KSME-A.2014.38.5.535
In the robust optimization field, the robustness of the objective function emphasizes an insensitive design. In general, the robustness of the objective function can be achieved by reducing the change of the objective function with respect to the variation of the design variables and parameters. However, in conventional methods, when an insensitive design is emphasized, the performance of the objective function can be deteriorated. Besides, if the numbers of the design variables are increased, the numerical cost is quite high in robust optimization for nonlinear programming problems. In this research, the robustness index for the objective function and a process of robust optimization are proposed. Moreover, a method using the supremum of linearized functions is also proposed to reduce the computational cost. Mathematical examples are solved for the verification of the proposed method and the results are compared with those from the conventional methods. The proposed approach improves the performance of the objective function and its efficiency.
Investigation on Friction Noise in Beam Structure Under Mode-Coupling by Using Analytical Finite-Element Squeal Model
Kang, Jaeyoung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 545~550
DOI : 10.3795/KSME-A.2014.38.5.545
This study provided the analytical finite element method estimating the friction-induced noise on the complex beam structure. The frictional contact model was theoretically constructed and applied to the analytical finite element squeal model. The numerical results showed that the beam structure was excited by the mode-coupling instability of the specific system modes. Also, the direction of friction was shown to influence on the dynamic instability of the modes. Besides, the unstable modal frequencies estimated from the numerical calculation were validated by the experiment of the actual beam structure.
Design of Lateral Controller for Autonomous Guidance of a Farm Tractor in Field Operations
Han, Kun Hee ; Lee, Ji Min ; Song, Bongsob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 551~557
DOI : 10.3795/KSME-A.2014.38.5.551
This paper presents a robust lateral controller for autonomous guidance of a farm tractor in field operations. Although mechanical steering actuators have recently been used for passenger vehicles, the steering actuator of the farm tractor is based on a hydraulic system, resulting in limited bandwidth and a larger time delay. Based on a kinematic tractor model with steering actuator dynamics, a nonlinear control technique called dynamic surface control is applied to design a robust lateral controller that compensates for uncertainty owing to steering actuator and road geometry. Finally, tracking performance and robustness of the proposed controller are validated via commercial tractor simulations, with respect to the time delay of the steering actuator and road geometry (e.g., up and down hills), on a given field with a constant friction coefficient.
Morphological Observation on Tribological Characteristic of Thermal Spray Coated Steel-Bar
Lee, Duk Gyu ; Cho, Hee Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 559~566
DOI : 10.3795/KSME-A.2014.38.5.559
Plasma coatings have been conducted to improve the mechanical properties of thermal resistance, wear resistance, corrosion resistance and thermal shock with respect to Great-Bar which is used as a carrier device for ironstone sintering under
. The surface coatings on the upper side of the Great-Bar exposed on extreme environments of high temperature, severe wear, corrosion and thermal shock extended the life time due to the barrier coating layer.
, WC coatings were applied to Great-Bar and their mechanical and chemical properties are analyzed by several experimental tests such as thermal resistance, wear resistance, corrosion resistance and thermal shock resistance. It shows excellent advantages with respect to wear, thermal shock and corrosion.
Design and Analysis of Piezoelectric Micro-Pump Using Traveling-Wave
Na, Yeong Min ; Lee, Hyun Seok ; Park, Jong Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 567~573
DOI : 10.3795/KSME-A.2014.38.5.567
Since the development of microelectromechanical systems (MEMS) technology for the medical field, various micro-fluid transfer systems have been studied. This paper proposes a micro-piezoelectric pump that imitates a stomach's peristalsis by using two separate piezoelectric elements, in contrast to existing micro-pumps. This piezoelectric pump is operated by using the valve-less traveling wave of peristalsis movement. If the piezoelectric plates at the two separated plates are actuated at the input voltage, a traveling wave occurs between the two plates. Then, the fluid migrates by the pressure difference generated by the traveling wave. Finite element analysis was performed to understand the mechanics of the combined system with piezoelectric elements, elastic structures, and fluids. The effects of design variables such as the chamber height and number of ceramics on the flow rate of the fluid were examined.
Optimal Design of Wind Turbine Tower Model Using Reliability-Based Design Optimization
Park, Yong-Hui ; Park, Hyun-Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 38, issue 5, 2014, Pages 575~584
DOI : 10.3795/KSME-A.2014.38.5.575
In this study, the NREL 5 MW wind turbine tower model was optimized according to the multi-body dynamics and reliability-based design. The mathematical model was defined as a link-joint system including dynamic characteristics derived from Timoshenko's beam theory. For the optimization problem, the sensitivities to variations in the tower thicknesses and inner and outer diameters were acquired and arranged in terms of safety and efficiency according to bending stress and buckling standards. An optimal design was calculated with the advanced first-order second moment method and used to define a finite element model for validation. The finite element model was simulated by static analysis. The relationship between the multi-body dynamic and finite element method throughout the process was investigated, and the optimal model, which had high endurance despite its low mass, was determined.