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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 36, Issue 12 - Dec 2012
Volume 36, Issue 11 - Nov 2012
Volume 36, Issue 10 - Oct 2012
Volume 36, Issue 9 - Sep 2012
Volume 36, Issue 8 - Aug 2012
Volume 36, Issue 7 - Jul 2012
Volume 36, Issue 6 - Jun 2012
Volume 36, Issue 5 - May 2012
Volume 36, Issue 4 - Apr 2012
Volume 36, Issue 3 - Mar 2012
Volume 36, Issue 2 - Feb 2012
Volume 36, Issue 1 - Jan 2012
Selecting the target year
Effect of Highly Pressurized Hydrogen Gas on Tensile Properties of a Low-Alloy Steel Used for Manufacturing CNG Storage Vessels
Lee, H.M. ; Jeong, I.H. ; Park, J.S. ; Nahm, S.H. ; Han, J.O. ; Lee, Y.C. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 829~833
DOI : 10.3795/KSME-A.2012.36.8.829
SNG (synthetic natural gas or substitute natural gas) could contribute greatly toward energy security. In addition, HCNG (or
) is expected to be used as a fuel gas for internal combustion engines and home appliances because it has extremely low emissions and high thermal efficiency. However, the hydrogen contained in SNG or HCNG can deteriorate the mechanical properties of the materials used in existing natural gas infrastructure. Therefore, it is necessary to investigate the effect of hydrogen on the mechanical properties of such materials so that SNG or HCNG can be transported and distributed safely and reliably. In this study, the effect of highly pressurized hydrogen gas on the tensile properties of a low-alloy steel used for manufacturing CNG storage vessels was investigated using the so-called hollow tensile specimen technique.
Evaluation of Thermal Fatigue Lifetimes of Cast Iron Brake Disc Materials
Goo, Byeong-Choon ; Lim, Choong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 835~841
DOI : 10.3795/KSME-A.2012.36.8.835
We measured the mechanical and thermal properties of four types of cast irons used for manufacturing the brake discs of railway vehicles. It was found that these properties could be controlled by varying the composition of Ni, Cr, and Mo. Thermal fatigue tests were carried out by using a thermal fatigue tester in which thermal cycles could be controlled. Thermal crack initiation and propagation were measured on cylindrical specimens. Finally, we simulated the thermal fatigue test procedure by finite element analysis and calculated the thermal fatigue lifetimes by Manson-Coffin's equation and the maximum principal strain. The estimated thermal fatigue lifetimes corresponded to the measured lifetimes when the total crack length was
Outer Shape Design of Rotating Medium Antenna Installed on Ship Mast
Cho, Ki-Dae ; Kim, Ki-Wan ; Kwon, Min-Sang ; Hong, Seong-Il ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 843~850
DOI : 10.3795/KSME-A.2012.36.8.843
To satisfy the operational requirements of surveillance radar and the operational concept of a ship combat system, an active-array-type antenna was designed using solid-state transmitters and receivers. The arrangement of the constituent electronic components of the antenna system, considerably large in size, and therefore, the antenna needs to be housed in a box. The rotational antenna system installed on a ship mast is installed in a sealed housing to protect the interior equipment from environmental conditions. The outer shape of the housing is that the antenna should be capable of rotating normally despite strong winds. Furthermore, in recent times, designs with low radar cross section (RCS) have attracted attention from the viewpoint of improving the stealth of the ship. In this light, four types of models are proposed for the outer shape design of the antenna system, and they are investigated from the viewpoint of low RCS design as well as wind load.
Design of Vertical Type Probe Tip Using Finite Element Analysis
Oh, Young-Ryun ; Kim, Yun-Jae ; Nam, Hyun-Suk ; Park, Ung-Gi ; Lee, Hak-Joo ; Kim, Jung-Yub ; Park, Jun-Hyub ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 851~856
DOI : 10.3795/KSME-A.2012.36.8.851
The design process of a micro-probe tip is very complicated and expensive. To avoid these problems, in this study, we used element (FE) analysis. To simplify design process. A new pre-probe tip (cobra-needle type) made of Ni and Co was designed by FE analysis. Experimental results were compared with those obtained by FE analysis to verify the reliability of the analysis. The contact force and over drive were respectively found to be 12.5 gf(Contact Force) and
(Over drive). We propose the new designed probe tip. Material of new designed probe tip is NiCo. Values of Property are 1~2 gf(Contact Force) and
Mechanical Properties of Laser-Welded Multi-Material Tailor-Welded Blanks
Nam, Ki-Woo ; Park, Sang-Hyun ; Lee, Kyu-Hyun ; Lee, Mun-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 857~863
DOI : 10.3795/KSME-A.2012.36.8.857
In this study, tailor-welded blanks(TWB) were formed between high-strength steel(SABC1470) and cold rolled steels(SPFH590 and SPFC980) to improve passenger safety and reduce the weight of cars. Multi-material TWB specimens were highly strengthened through the heat treatment of SABC1470. The change in tensile strength caused by the stand-by time until water cooling after stamping and the deformation behavior of high-speed bending in a statically indeterminate condition such as in the center-pillar were evaluated. Multi-material TWB specimens that were heat-treated at the same temperature tended to show a decrease in tensile and yield strength, depending on the stand-by time until water cooling. On the other hand, Multi-material TWB specimens(SABC1470+SPFH590) that were heat treated at
showed good properties that were suitable for ensuring passenger safety in car accidents. From the viewpoint of passenger safety, it is best to use SABC1470 and SPFH590 in the upper and lower area of the center-pillar, respectively.
Research on Pre- and Post-Processor for Analysis of Proportional Solenoid Valve
Yun, Dong-Won ; Ham, Sang-Yong ; Park, Jung-Ho ; Yun, So-Nam ; Kim, Chil-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 865~871
DOI : 10.3795/KSME-A.2012.36.8.865
In this study, a wrapping program was developed to analyze a proportional solenoid valve more easily using a conventional finite element method (FEM) tool. To achieve an accurate solution when analyzing a solenoid valve, finite element analysis (FEA) is more suitable than a lumped method. To develop a program for modeling and analyzing the valve performance using FEA code for the user's convenience, it is assumed that the solenoid valve is composed of some simple geometries, namely, a triangle and a rectangle. This assumption helps users to model a solenoid valve simply. To check the feasibility of the developed code, an actual solenoid valve is analyzed, and it is found that the code can suitably analyze this valve. The characteristics of the proportional valve are well identified as indicated through the graphs.
Sensitivity Validation Technique for Sequential Kriging Metamodel
Huh, Seung-Kyun ; Lee, Jin-Min ; Lee, Tae-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 873~879
DOI : 10.3795/KSME-A.2012.36.8.873
Metamodels have been developed with a variety of design optimization techniques in the field of structural engineering over the last decade because they are efficient, show excellent prediction performance, and provide easy interconnections into design frameworks. To construct a metamodel, a sequential procedure involving steps such as the design of experiments, metamodeling techniques, and validation techniques is performed. Because validation techniques can measure the accuracy of the metamodel, the number of presampled points for an accurate kriging metamodel is decided by the validation technique in the sequential kriging metamodel. Because the interpolation model such as the kriging metamodel based on computer experiments passes through responses at presampled points, additional analyses or reconstructions of the metamodels are required to measure the accuracy of the metamodel if existing validation techniques are applied. In this study, we suggest a sensitivity validation that does not require additional analyses or reconstructions of the metamodels. Fourteen two-dimensional mathematical problems and an engineering problem are illustrated to show the feasibility of the suggested method.
Prediction of Fracture Strength of Woven CFRP Laminates According to Fiber Orientation
Kang, Min-Sung ; Park, Hong-Sun ; Choi, Jung-Hun ; Koo, Jae-Mean ; Seok, Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 881~887
DOI : 10.3795/KSME-A.2012.36.8.881
CFRP composite materials have been widely used in various fields of engineering because of their excellent properties. They show high specific stiffness and specific strength compared with metallic materiasl. Woven CFRP composite materials are fabricated from carbon fibers with two orientation angles (
), which influences the mechanical properties. Therefore, woven CFRP composite materials show different types of fracture behavior according to the load direction. Therefore, the fracture behavior of these materials needs to be evaluated according to the load direction when designing structures using these materials. In this study, we evaluate the fracture strength of plain-woven CFRP composite materials according to the load direction. We performed tests for six different angles (load direction:
) and estimated the fracture strength for an arbitrary fiber angle by using the modified Tan's theory and harmonic function.
Analysis of Characteristics of CFRP Composites Exposed Under High-Temperature and High-Humidity Environment for a Long Period
Hong, Suk-Woo ; Ahn, Sang-Soo ; Koo, Jae-Mean ; Seok, Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 889~895
DOI : 10.3795/KSME-A.2012.36.8.889
Carbon fiber reinforced plastic (CFRP) composites have high specific stiffness and high specific strength. Therefore, they are increasingly being use, instead of conventional metallic materials in the aviation and automobile industries, where there is a strong demand for lightweight materials. In aircraft, the fuselage is exposed to severe conditions of high temperatures and high humidity. Therefore, it is necessary to estimate the strength of CFRP composites under real conditions from the viewpoint of aircraft safety. In this study, CFRP specimens were immersed in distilled water at
for a long time. Then, tensile tests were performed on these specimens, and the fracture characteristics of the fractured surfaces were analyzed using SEM. A fatigue test was performed on specimens immersed for 300 days with R=0.1, and it was confirmed that the fatigue life deteriorated in immersed specimens compared to specimens that were not immersed.
Barrel Rifling Shape Optimization by Using Design of Experiment Approach
Kang, Dae-Oh ; Woo, Yoon-Hwan ; Cha, Ki-Up ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 897~904
DOI : 10.3795/KSME-A.2012.36.8.897
The rifling design problem has continuous-type shape variables and an integral number of riflings. In addition, it requires considerable time for analysis because its behavior should be described by a nonlinear finite element model (FEM). Therefore, this study presents an efficient design process for rifling based on a design of experiment (DOE) approach. First, Bose's orthogonal array is used to represent 25 runs for four design variables including three shape variables and one integer variable. Then, nonlinear FE analyses are performed. Next, to minimize the bullet resistance without affecting the bullet velocity and bullet rotational angle immediately before a bullet leaves the gun barrel, a what-if design is performed. In the proposed what-if design, a functional including the design objective and constraints is constructed and effect analysis is performed by using the functional. It is found that the new design obtained from the what-if design shows better results than the current one.
Dynamic Behavior Analysis of Floating Offshore Wind Turbine Including Flexible Effects of Tower and Blade
Jung, Hye-Young ; Sohn, Jeong-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 905~911
DOI : 10.3795/KSME-A.2012.36.8.905
To establish a floating offshore wind turbine simulation model, a tension leg platform is added to an onshore wind turbine. The wind load is calculated by using meteorological administration data and a power law that defines the wind velocity according to the height from the sea surface. The wind load is applied to the blade and wind tower at a regular distance. The relative Morison equation is employed to generate the wave load. The rated rotor speed (18 rpm) is applied to the hub as a motion. The dynamic behavior of a 2-MW floating offshore wind turbine subjected to the wave excitation and wind load is analyzed. The flexible effects of the wind tower and the blade are analyzed. The flexible model of the wind tower and blade is established to examine the natural frequency of the TLP-type offshore wind turbine. To study the effect of the flexible tower and blade on the floating offshore wind turbine, we modeled the flexible tower model and flexible tower-blade model and compared it with a rigid model.
Pressure Analysis of Plantar Musculoskeletal Fascia while Walking using Finite Element Analyses
Jeon, Seong-Mo ; Kim, Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 913~920
DOI : 10.3795/KSME-A.2012.36.8.913
An efficient 3D finite element walking model that considers the detailed shapes of muscles, ligaments, bones, skin, and soles was developed based on a real computed tomography (CT) scan image of a foot, and nonlinear contact analyses were performed to investigate pressure changes. The highest pressure occurs at the rear bottom of the foot when standing and walking. The pressure on the outsole with a curved foot bottom surface is lessened and distributed over a wider area than in the case of a flat outsole. The result shows that a shoe sole shape optimized for diabetes patients can relieve the foot pressure concentration and prevent further worsening of symptoms.
Reliability-Based Design Optimization Using Akaike Information Criterion for Discrete Information
Lim, Woo-Chul ; Lee, Tae-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 921~927
DOI : 10.3795/KSME-A.2012.36.8.921
Reliability-based design optimization (RBDO) can be used to determine the reliability of a system by means of probabilistic design criteria, i.e., the possibility of failure considering stochastic features of design variables and input parameters. To assure these criteria, various reliability analysis methods have been developed. Most of these methods assume that distribution functions are continuous. However, in real problems, because real data is often discrete in form, it is important to estimate the distributions for discrete information during reliability analysis. In this study, we employ the Akaike information criterion (AIC) method for reliability analysis to determine the best estimated distribution for discrete information and we suggest an RBDO method using AIC. Mathematical and engineering examples are illustrated to verify the proposed method.
Analysis of Impact Characteristics of Bonded Dissimilar Materials for Center Pillar
Nam, Ki-Woo ; Park, Sang-Hyun ; Yoo, Jung-Su ; Lee, Sang-Mun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 929~934
DOI : 10.3795/KSME-A.2012.36.8.929
This study was carried out to analyze the dynamic characteristics of laser tailor-welded blanks (TWBs) made of dissimilar materials. The analysis was performed using Hyper Works 10.0 with Solver LS-DYNA v.971. 2D-Shell was used as the modeling element, and the number of elements and nodes was 35,641 and 36,561, respectively. The impact speed was 10 km/h. To analyze the impact characteristics according to the height of the weld line for the upper and lower parts of the center pillar, the length of the lower part was set as 300 and 400 mm. When the lower part was made of SPFC980 steel with a length of 300 mm, the deformation was the smallest and the absorbed energy of the impact force was the largest. On based the lower part of center pillar, the position of TWB shows the shorter and the better value. In other words, the performance depended on the proportion of the upper part made of high-strength SABC1470 steel. A lower part made of SPFH590 steel showed large deformation. In contrast, a lower part made of SPFC980 steel showed significantly lesser deformation. Therefore, the impact performance of a lower part made of SPFC980 steel with a length of 300 mm showed the best analysis result.
Energy Absorption of Collision Post Based on North American CFR Regulations for Railway Vehicles
Kim, Seung-Tech ; Jeong, Ji-Ho ; Choi, Jeong-Yong ; Woo, Kwan-Je ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 935~943
DOI : 10.3795/KSME-A.2012.36.8.935
In accidents involving the collision of railway vehicles, there is a risk that structural members might penetrate the cab frame of the railway vehicle in the space in which the driver or passengers are seated. To reduce this risk, worldwide, studies on the collision of railway vehicles are underway. In North America, the Code of Federal Regulations (CFR) was revised in 2010 to include crush criteria for a collision and the corner post in an end frame. In this study, a crush analysis and crush test for a collision post and a crash analysis for a rigid cylinder were performed according to the CFR. The analysis and test results were compared and reviewed. This study aims to determine the usefulness of crush analysis for developing various end frames, and to understand the crush and crash characteristics and review the accuracy of the analysis.
Static and Dynamic Finite Element Analyses of a Bulk-Cement Trailer
Kim, Jin-Gon ; Lee, Jae-Gon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 36, issue 8, 2012, Pages 945~951
DOI : 10.3795/KSME-A.2012.36.8.945
In this study, we analyze the static and dynamic characteristics of a bulk-cement trailer with a simpler structure that carries powders. The commercial software ANSYS is used to prepare a detailed three-dimensional model of the chassis frame and tank body that bear most of the load of a bulk-cement trailer for the finite element analysis. Modal analysis is conducted to examine the dynamic characteristics of the trailer body, and static analysis shows weak links in the structure. Finally, we propose a method to increase the strength of vulnerable areas and to reduce the weight of the trailer by applying the Taguchi method.