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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 37, Issue 12 - Dec 2013
Volume 37, Issue 11 - Nov 2013
Volume 37, Issue 10 - Oct 2013
Volume 37, Issue 9 - Sep 2013
Volume 37, Issue 8 - Aug 2013
Volume 37, Issue 7 - Jul 2013
Volume 37, Issue 6 - Jun 2013
Volume 37, Issue 5 - May 2013
Volume 37, Issue 4 - Apr 2013
Volume 37, Issue 3 - Mar 2013
Volume 37, Issue 2 - Feb 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Investigation of the Robustness Index of the Objective Function in Robust Optimization
Lee, Se-Jung ; Jeong, Seong-Beom ; Park, Gyung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 589~599
DOI : 10.3795/KSME-A.2013.37.5.589
The concept of robust optimization is based on Taguchi's method. Especially, robustness indices of objective function pursue an insensitive and conservative design when there are variations on design variables and parameters. To accomplish the purpose, various robustness indices on the objective function have been developed. However, it can be caused limitations to develop the robustness index, because there is difference between the Taguchi's method and robust optimization. In this paper, an investigation is performed to identify the characteristics and the drawbacks of the previous studies. To achieve the purpose, evaluations are conducted by using the examples which have both a deterministic optimum and a robust optimum. Moreover, a new viewpoint as well as a robustness index using a supremum value of the objective function is proposed based on the investigation.
Development and Validation of Wheel Loader Simulation Model
Oh, Kwangseok ; Yun, Seungjae ; Kim, Hakgu ; Ko, Kyungeun ; Yi, Kyongsu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 601~607
DOI : 10.3795/KSME-A.2013.37.5.601
This paper presents the development and validation of a wheel loader simulation model. The objective of doing so is to evaluate the performance of the wheel loader and improve its overall performance using Matlab/Simulink. The wheel loader simulation model consists of 4 parts: mechanical/hydraulic powertrain model and vehicle/working dynamic model. An integrated simulation model is required to evaluate and improve the performance of the wheel loader. It is expected that this model will be applied to fuel economizing, improving the pace of operation by using the hybrid system, and the intelligent wheel loader. The performance of the proposed simulation model has been validated by using Matlab/Simulink to compare the driving and the working experimental data.
Design of Near-Minimum Time Path Planning Algorithm for Autonomous Driving
Kim, Dongwook ; Kim, Hakgu ; Yi, Kyongsu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 609~617
DOI : 10.3795/KSME-A.2013.37.5.609
This paper presents a near-minimum time path planning algorithm for autonomous driving. The problem of near-minimum time path planning is an optimization problem in which it is necessary to take into account not only the geometry of the circuit but also the dynamics of the vehicle. The path planning algorithm consists of a candidate path generation and a velocity optimization algorithm. The candidate path generation algorithm calculates the compromises between the shortest path and the path that allows the highest speeds to be achieved. The velocity optimization algorithm calculates the lap time of each candidate considering the vehicle driving performance and tire friction limit. By using the calculated path and velocity of each candidate, we calculate the lap times and search for a near-minimum time path. The proposed algorithm was evaluated via computer simulation using CarSim and Matlab/Simulink.
Stress Analysis for Bendable Electronic Module Under Thermal-Hygroscopic Complex Loads
Han, Changwoon ; Oh, Chulmin ; Hong, Wonsik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 619~624
DOI : 10.3795/KSME-A.2013.37.5.619
A bendable electronic module is developed. In this module, thin silicon electronic chips are embedded in a polymer-based encapsulating adhesive between flexible copper-clad polyimide layers. During the qualification test of a harshly thermal-hygroscopic complex loading condition, delaminations occur inside the module layers. A finite element model is developed for the module. To investigate the effect of hygroscopic stress on delamination, the results of the thermal and thermal-hygroscopic loads are compared. The analysis results reveal that the hygroscopic effect more strongly affects delamination than does the thermal effect. The potential failure mechanisms of the module are investigated based on the stress analysis.
Tribological Influence of Kinematic Oil Viscosity Impregnated in Nanopores of Anodic Aluminum Oxide Film
Kim, Dae-Hyun ; Ahn, Hyo-Sok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 625~630
DOI : 10.3795/KSME-A.2013.37.5.625
The friction behavior of a 60-
-thick anodic aluminum oxide (AAO) film having cylindrical nanopores of 45-nm diameter was investigated as a function of impregnated oil viscosity ranging from 3.4 to 392.6 cSt. Reciprocating ball-on-flat sliding friction tests using a 1-mm-diameter steel ball as the counterpart were carried out with normal load ranging from 0.1 to 1 N in an ambient environment. The friction coefficient significantly decreased with an increase in the oil viscosity. The boundary lubrication film remained effectively under all test conditions when high-viscosity oil was impregnated, whereas it was easily destroyed when low-viscosity oil was impregnated. Thin plastic deformed layer patches were formed on the worn surface with high-viscosity oil without evidence of tribochemical reaction and transfer of counterpart material.
J-Integral Estimate for Circumferential Cracked Pipes Under Primary and Secondary Stress in R6, RCC-MR A16
Nam, Hyun Suk ; Oh, Chang Young ; Kim, Yun Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 631~640
DOI : 10.3795/KSME-A.2013.37.5.631
This paper provides a comparison of the J-integral estimation method under combined primary and secondary stress in the R6, RCC-MR A16 code. The comparisons of each code are based on finite element analysis using ABAQUS with regard to the crack shape, crack depth, and magnitude of secondary load. The estimate of the R6 code is conservative near
, and that of the RCC-MR A16 code is conservative near
. As a result, this paper proposes a modified method of J-integral estimation in the R6, RCC_MR A16 code. The J-integral using the modified method corresponds to the finite element analysis result.
Experimental Study on Dynamic Characteristics of Structurally Tailored Isotropic Box Beams
Kim, Kyoung-Duck ; Kim, Jun-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 641~648
DOI : 10.3795/KSME-A.2013.37.5.641
A beam is a major load-carrying member in many engineering structures. Beams with properly designed cross sections and stiffeners are required to enhance the structural properties. Such a design may cause various coupling behaviors, and therefore, an accurate analysis is essential for the proper design of beams. In this research, we manufactured box-beams with stiffeners, which mimic the out-of-plane composite bending-shear coupling behavior reported in literature. A modal test is carried out to obtain the dynamic characteristics, such as natural frequencies and mode shapes, of the box-beam. The obtained results are compared with those of 3D FEM, which confirm that the out-of-plane bending-shear coupling behavior reported in literature is possible. The coupling behavior can be controlled by the proper design of the stiffeners.
Stress Distribution in the Dissimilar Metal Butt Weld of Nuclear Reactor Piping due to the Simulation Technique for the Repair Welding
Lee, Hwee-Seung ; Huh, Nam-Su ; Kim, Jin-Su ; Lee, Jin-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 649~655
DOI : 10.3795/KSME-A.2013.37.5.649
During welding, the dissimilar metal butt welds of nuclear piping are typically subjected to repair welding in order to eliminate defects that are found during post-weld inspection. It has been found that the repair weld can significantly increase the tensile residual stress in the weldment, and therefore, accurate estimation of the weld residual stress due to repair weld, especially for dissimilar metal welds using Ni-based alloy 82/182 in nuclear components, is of great importance in order to assess susceptibility to primary water stress corrosion cracking. In the present study, the stress distributions of dissimilar metal butt welds in nuclear reactor piping subjected to repair weld were investigated based on detailed nonlinear finite element analyses. Particular emphasis was placed on the variation of the stress distribution in the dissimilar metal butt weld according to the finite element welding analysis sequence for the repair welding process.
Measurement of Mechanical Property and Thermal Expansion Coefficient of Carbon-Nanotube-Reinforced Epoxy Composites
Ku, Min Ye ; Kim, Jung Hyun ; Kang, Hee Yong ; Lee, Gyo Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 657~664
DOI : 10.3795/KSME-A.2013.37.5.657
By using shear mixing and ultrasonication, we fabricated specimens of well-dispersed multi-walled carbon nanotube composites. To confirm the proper dispersion of the filler, we used scanning electron microscopy images for quantitative evaluation and a tensile test for qualitative assessment. Furthermore, the coefficients of thermal expansion of several specimens having different filler contents were calculated from the measured thermal strains and temperatures of the specimens. Based on the microscopy images of the well-dispersed fillers and the small deviations in the measurements of the tensile strength and stiffness, we confirmed the proper dispersion of nanotubes in the epoxy. As the filler contents were increased, the values of tensile strength increased from 58.33 to 68.81 MPa, and those of stiffness increased from 2.93 to 3.27 GPa. At the same time, the coefficients of thermal expansion decreased. This implies better thermal stability of the specimen.
High-Temperature Design of Sodium-to-Air Heat Exchanger in Sodium Test Loop
Lee, Hyeong-Yeon ; Eoh, Jae-Hyuk ; Lee, Yong-Bum ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 665~671
DOI : 10.3795/KSME-A.2013.37.5.665
In a Korean Generation IV prototype sodium-cooled fast reactor (SFR), various types of high-temperature heat exchangers such as IHX (intermediate heat exchanger), DHX (decay heat exchanger), AHX (air heat exchanger), FHX (finned-tube sodium-to-air heat exchanger), and SG (steam generator) are to be designed and installed. In this study, the high-temperature design and integrity evaluation of the sodium-to-air heat exchanger AHX in the STELLA-1 (sodium integral effect test loop for safety simulation and assessment) test loop already installed at KAERI (Korea Atomic Energy Research Institute) and FHX in the SEFLA (sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger) test loop to be installed at KAERI have been performed. Evaluations of creep-fatigue damage based on full 3D finite element analyses were conducted for the two heat exchangers according to the high-temperature design codes, and the integrity of the high-temperature design of the two heat exchangers was confirmed.
Experimental Investigation of Creep Groan Noise
Kang, Kyung Min ; Jeon, Hyun Cheol ; Kang, Yeon June ; Cho, Min Hyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 673~678
DOI : 10.3795/KSME-A.2013.37.5.673
Creep groan noise occurs at low frequencies immediately after releasing brake pressure or when a car stops. This noise can be used to predict problems in not only the brake system but also the vehicle system. Because of its complexity, it is difficult to determine its characteristics. Therefore, most improvements are conducted by changing the brake pad, and it still remains difficult to conduct a test using a vehicle. In this study, the characteristics of creep groan noise and the effects from a vehicle system are investigated by using vehicles and an NVH chassis-dynamometer through various tests. A new evaluation method for creep groan noise by using a vehicle is proposed, and the possibility of reduction schemes from the viewpoint of the vehicle system is confirmed from the results mentioned above.
Development of Rattle and Squeak Detection Methodology Considering Characteristics of Road Vibration Input
Lyu, Su Jung ; Jun, In Ki ; Choi, Jae Min ; Lee, Won Ku ; Woo, Jae Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 679~683
DOI : 10.3795/KSME-A.2013.37.5.679
BSR noise emerges in a vehicle as a result of road vibrations, engine vibrations, and speaker vibrations. BSR noise occurs with an irregular impact or stick slip friction phenomenon as the influence of the resonance mode when the vibration input load is transferred along poor joint and contacting pairs of the system. A sub-structure method of finite element analysis is required to detect impacts and slip in the full vehicle model. This study presents a method for sub-structure modeling and a rattle and squeak detection methodology that considers the characteristics of road vibration inputs.
Development of Load-Cell-Based Anemovane
Jeon, Byeong Ha ; Han, Dong Seop ; Lee, Kwon-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 685~691
DOI : 10.3795/KSME-A.2013.37.5.685
A load-cell-type anemovane operates based on wind vector properties. The developed load-cell-type anemovane is of a fixed type in which the wing does not rotate, unlike in the case of existing anemovanes. The load-cell-type anemovane is required to accurately derive the correlation between the load ratio and the wind direction in order to develop a qualified product. This is because the load ratio repeats every
owing to the use of four load cells, and its value varies nonlinearly according to the wind direction. In this study, we compared analytical results with experimental results. Fluid analysis was carried out using ANSYS CFX. Furthermore, the prototype was tested using a self-manufactured wind tunnel. The wind direction was selected as the design variable. 13 selected wind direction conditions ranging from
with an interval of
for analysis were defined. Furthermore, 10 wind direction conditions with an interval of
for the experiment were defined. We derived the relations between the pressure ratio and the wind direction through the experiment and fluid analysis.
Development of Procedural 2D CAD Data Translator Supporting ISO 10303 STEP
Kim, Byung Chul ; Cheon, Sang-Uk ; Mun, Duhwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 693~705
DOI : 10.3795/KSME-A.2013.37.5.693
Procedural models have the advantage of being easy to edit simply by changing the values of the parameters of their constructional operations. In previous studies, we have introduced an approach for representing procedural 2D CAD models in ISO 10303 and developed ISO 10303-112 for the exchange of procedural 2D CAD models. In this paper, a method for the development of a procedural 2D CAD data translator supporting ISO 10303-112 is suggested. Furthermore, the core techniques applied to the translator are presented. The feasibility of the proposed method was demonstrated through data exchange experiments using a prototype translator.
Study on Design of Coupling Bolt for Shaft in Power Plant
Jeong, HoSeung ; Son, ChangWoo ; Cho, JongRae ; Kim, Tae Hyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 707~713
DOI : 10.3795/KSME-A.2013.37.5.707
Coupling bolts have replaced conventional fitted bolts in applications where the operator's safety during assembly/disassembly is of concern or where the cost of process interruption is significant. Coupling bolts have been installed on rotating flange couplings in a wide range of marine and power applications worldwide. Their use has been approved by all leading international and national classification societies and regulatory bodies. A coupling bolt is a hydraulically tensioned fitted bolt that creates a stable and rigid link between coupling flanges and simplifies assembly and disassembly. We measure the bolt dimensions for reverse engineering and study the standard of assembly-load using a mechanical formula in order to localize a coupling bolt for a shaft in a power plant. We experimentally obtain the friction coefficient and confirm the condition of bolt sets through structure analysis. We show the variation of contact pressure for the shape parameter in order to consider the result when redesigning a bolt.
Study on Seismic Analysis and Test for Seismic Qualification of 245kV GIS
Kim, Yu-Gyeong ; Kwon, Tae-Hoon ; Jeong, Yeong-Jin ; Kim, Hong-Tae ; Kim, Young-Joong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 37, issue 5, 2013, Pages 715~722
DOI : 10.3795/KSME-A.2013.37.5.715
Gas insulated switchgear is large-sized electric equipment for providing a reliable supply of electric power. Recently, seismic tests of electric equipment using a shaking table have been mandated because seismic performance has become an increasingly important issue. However, basic analysis methods continue to be used because some electric equipment is too large for shaking table facilities. Thus, a reliable analysis method should be developed for large-scale electric equipment. This study aims to evaluate the seismic qualification of a 245kV GIS in accordance with IEEE-693 and to validate the analysis method by comparing it with test results. Both the test and the analysis showed that the 245kV GIS has proper seismic safety. Furthermore, the differences between the analysis and the test results are less than 10% for an accurately given mass, stiffness, and input acceleration. It is expected that this study can be used for the seismic qualification of large-scale electrical structures.