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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 34, Issue 12 - Dec 2010
Volume 34, Issue 11 - Nov 2010
Volume 34, Issue 10 - Oct 2010
Volume 34, Issue 9 - Sep 2010
Volume 34, Issue 8 - Aug 2010
Volume 34, Issue 7 - Jul 2010
Volume 34, Issue 6 - Jun 2010
Volume 34, Issue 5 - May 2010
Volume 34, Issue 4 - Apr 2010
Volume 34, Issue 3 - Mar 2010
Volume 34, Issue 2 - Feb 2010
Volume 34, Issue 1 - Jan 2010
Selecting the target year
A Study on the Improvement of a Damageability and Repairability by Improving Mounting Structure of a Bumper for Passenger Cars
Kim, Ji-Won ; Park, In-Song ; Lee, Chang-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 1~9
DOI : 10.3795/KSME-A.2010.34.1.1
The purpose of this study is to analyze the bumper mounting structure of passenger vehicles at low speed collision. In order to improve the repairability and damageability of the vehicle, the low speed crash tests of RCAR(Research Council for Automobile Repairs) standard(front & rear 15km/h 40% offset crash test) were carried out for analysis of 3 different types of bumper mounting structures. The results of experiments show that the impact energy absorbing ability of bumper stay with rectangular crash box type vehicle which is inserted into the bumper rail was superior to another two different bumper mounting structures that are applied to many passenger vehicles. In this thesis, well designed bumper mounting structure such as rectangular crash box type can enhance the safety of occupants as well as contribute to reduce repair cost at low collision accident by improving repairability and damageability of vehicle.
Feature Analysis Based on Beta Distribution Model for Shaving Tool Condition Monitoring
Choe, Deok-Ki ; Kim, Seong-Jun ; Oh, Young-Tak ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 11~18
DOI : 10.3795/KSME-A.2010.34.1.11
Tool condition monitoring (TCM) is crucial for improvement of productivity in manufacturing process. However, TCM techniques have not been applied to monitor tool failure in an industrial gear shaving application. Therefore, this work studied a statistical TCM method for monitoring gear shaving tool condition. The method modeled the vibration signal of the shaving process using beta probability distribution in order to extract the effective features for TCM. Modeling includes rectifying for converting a bi-modal distribution into a unimodal distribution, estimating the parameters of beta probability distribution based on method of moments. The performance of features obtained from the proposed method was evaluated and discussed.
Mis-Match Limit Load Analyses and Fracture Mechanics Assessment for Welded Pipe with Circumferential Crack at the Center of Weldment
Song, Tae-Kwang ; Jeon, Jun-Young ; Shim, Kwang-Bo ; Kim, Yun-Jae ; Kim, Jong-Sung ; Jin, Tae-Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 19~26
DOI : 10.3795/KSME-A.2010.34.1.19
In this paper, limit load analyses and fracture mechanics analyses were conducted via finite element analyses for the welded pipe with circumferential crack at the center of the weldment. Systematic changes for strength mismatch ratio, width of weldment, crack shape and thickness ratio of the pipe were considered to provide strength mismatch limit load. And J-integral calculations based on reference stress method were conducted for two materials, stainless steel and ferritic steel. Reference stress defined by provided strength mis-match limit load gives much more accurate J-integral.
Design of Magnetic Circuit with Minimum Leakage Using Response Surface Methodology
Park, Jin-Hun ; Kwon, Jung-Hak ; Hwang, Sang-Mun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 27~33
DOI : 10.3795/KSME-A.2010.34.1.27
This paper focuses on the design of microspeakers with minimum flux leakage, for use in radiotelegraphy. The response surface methodology (RSM) is applied as the optimization technique for obtaining a large magnetic force and a small flux leakage on diaphragm. The object functions of this optimization are the magnetic force and the flux leakage along three factors; pole piece thickness, magnet grade and yoke thickness, which are determined by the design of the experiment. The magnetic force and the flux leakage are calculated for each condition and optimized by results evaluated with RSM. For a pole piece thickness of 0.9 mm, a magnet grade of N42H and a yoke thickness of 0.75 mm, the magnetic force is satisfied as initial model and flux leakage is decreased to 11.8% than initial model.
Study on the Experimental Identification of Surface Roughness Using Laser Scattering Image
Hong, Yeon-Ki ; Kim, Gyung-Bum ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 35~41
DOI : 10.3795/KSME-A.2010.34.1.35
In this paper, surface roughness has been experimentally identified using laser scattering images. The parameters and optical deflected rays of laser scattering are investigated on laser scattering system, and then their optimum parameters on grinding surfaces are selected using design of experiment. The application of the optimum parameters results in featured laser scattering images, in which the mean of vertical scattering distributions is regarded as a feature. It is shown that the feature of laser scattering distributions is linearly increased according to grinding surface roughness and so the information can be used as important factor for the measurement and evaluation of various surface roughness. In the future, the performance of the proposed laser scattering method will be evaluated using AFM.
Creep Characteristics Verification of FE Model for SnPb Solder
Han, Chang-Woon ; Park, No-Chang ; Oh, Chul-Min ; Hong, Won-Sik ; Song, Byeong-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 43~48
DOI : 10.3795/KSME-A.2010.34.1.43
The heat sink system for a main board in a network server computer is built on printed circuit board by an anchor structure, mounted by eutectic SnPb solder. The solder creeping is caused by a constant high temperature condition in the computer and it eventually makes fatal failures. The FE model is used to calculate the stress and predict the life of soldered anchor in the computer. In the model, Anand constitutive equation is employed to simulate creep characteristics of solder. The creep test is conducted to verify and calibrate the solder model. A special jig is designed to mitigate the flexure of printed circuit board and to get the creep deformation of solder only in the test. Test results are compared with analysis and calibration is conducted on Anand model`s constants. Precise life prediction of soldered anchor in creep condition can be performed by this model.
Experimental Analysis of Fretting Wear Behaviors in Elastic Deformable Contacts
Lee, Young-Ho ; Kim, Hyung-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 49~54
DOI : 10.3795/KSME-A.2010.34.1.49
Fretting wear behavior under elastic deformable contacts was experimentally examined by using a simulated dual cooled fuel rod and its supporting structure. As this fuel rod has larger outer diameter than the typical solid rod to accommodate sufficient internal flow, new supporting structure geometries should be designed and their reliabilities (i.e. vibration characteristics, fretting wear resistance, etc.) are also examined with both analytical and experimental methods. In this study, the supporting structure characteristics and fretting wear behaviors are analyzed and examined by using one of the supporting structure candidates which has an embossing shape. The supporting structure characteristics were examined by using a specially designed test rig and their results were compared with that of analytical method. Based on the test results, the relationship between the supporting structure characteristics and their fretting wear behaviors was discussed in detail.
Fatigue Fracture Assessment of Honeycomb Composite Side-Wall Panel Joint for the KTX Tilting Car Body
Jeong, Dal-Woo ; Kim, Jung-Seok ; Choi, Nak-Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 55~60
DOI : 10.3795/KSME-A.2010.34.1.55
The honeycomb composite joint structure designed for application to a tilting KTX railroad car body is subjected to bending loads of a cantilever type. Honeycomb sandwich composite panel-joint attached in the real tilting car body was fabricated and sectioned as several beam-joint specimens for the bending test. The fracture behaviors of these specimens under static loads were different from those under cyclic loads. Static bending loads caused shear deformation and fracture in the honeycomb core region, while fatigue cyclic bend loading caused delamination along the interface between the composite skin and the honeycomb core, and/or caused a fracture in the welded part jointed with the steel under-frame. These fracture behaviors could occur in other industrial honeycomb composite joints with similar sub-structures, and be used for improving design parameters of a honeycomb composite joint structure.
Creep Behavior of a PZT Wafer Under Tensile Stress: Experiments and Modeling
Kim, Sang-Joo ; Lee, Chang-Hoan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 61~65
DOI : 10.3795/KSME-A.2010.34.1.61
A commercially available soft PZT wafer that is poled in thickness direction is subjected to longitudinal tensile stress loading in both short and open-circuit conditions. Variations of electric displacement in thickness direction and in-plane strains are measured over time during the loading. Different material responses in the two electrical boundary conditions are explained by the effects of piezoelectrically produced internal electric field on linear material moduli and domain switching mechanisms. Finally, a free energy model of normal distribution is introduced to explain the observed creep behavior, and its predictions are compared with experimental observations.
A Study on the Evaluation of the Fracture Toughness for the Narrow Gap Welding Part of Nuclear Piping
Huh, Yong ; Park, Soo ; Sin, In-Hwan ; Seok, Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 67~72
DOI : 10.3795/KSME-A.2010.34.1.67
The fracture toughness for the LBB analysis of piping is generally determined by the J-integral according to ASTM E1820. However, since this evaluates a base metal, the fracture toughness for narrow gap welding can be differently than the real value. This study evaluated the plastic factor of the narrow gap welding part of a nuclear piping with SA508 Cl.1a and SA312 TP316. Also, it performed the fracture toughness test for the narrow gap welding part and applied the new plastic
factor equation by Huh, et al. and then compared the results with those according with the ASTM standard.
Estimation of Measurement Uncertainty in Evaluation of Tensile Properties
Huh, Y.H. ; Lee, H.M. ; Kim, D.J. ; Park, J.S. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 73~78
DOI : 10.3795/KSME-A.2010.34.1.73
Estimation of tensile properties measurement uncertainty of material was carried out. Sources of uncertainty affecting the measurement of tensile properties were classified and analyzed. The models for uncertainty evaluation of measurands to be determined from tensile test, such as elastic modulus, yield strength and tensile strength, were suggested and derived from the mathematical relations, corresponding to the respective measurands, and the measuring quantities by calculating each sensitivity coefficient of the quantities. Based on these models, the uncertainty of the tensile properties was evaluated from the experimental data of SUS316LN determined according to ISO 6892.
Prediction of Weld Residual Stress of Narrow Gap Welds
Yang, Jun-Seog ; Heo, Nam-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 79~83
DOI : 10.3795/KSME-A.2010.34.1.79
The conventional welding technique such as shield metal arc welding has been mostly applied to the piping system of the nuclear power plants. It is well known that this welding technique causes the overheating and welding defects due to the large groove angle of weld. On the other hand, the narrow gap welding(NGW) technique has many merits, for instance, the reduction of welding time, the shrinkage of weld and the small deformation of the weld due to the small groove angle and welding bead width comparing with the conventional welds. These characteristics of NGW affect the deformation behavior and the distribution of welding residual stress of NGW, thus it is believed that the residual stress results obtained from conventional welding procedure may not be applied to structural integrity evaluation of NGW. In this paper, the welding residual stress of NGW was predicted using the nonlinear finite element analysis to simulate the thermal and mechanical effects of the NGW. The present results can be used as the important information to perform the flaw evaluation and to improve the weld procedure of NGW.
Mechanical Properties of Friction Welded SM 45C-SF 45 Joints for Automobile Reverse Idle Gear Shaft Applications
Kong, Yu-Sik ; Yun, Seong-Pil ; Kim, Seon-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 85~90
DOI : 10.3795/KSME-A.2010.34.1.85
Friction welding is a common practice to join axially symmetrical parts for automobile industry applications. The shaft for automobile reverse idle gear is generally produced by forging steel, SF 45. This method is not so good because of high cost of material and production. In this study, in order to investigate the possibility of application of SM 45C to SF 45 dissimilar friction welding, the dissimilar friction welded joints were performed using 20 mm diameter solid bar in forging steel(SF 45) to carbon steel(SM 45C). The optimal friction welding parameters were selected to ensure reliable quality welds on the basis of visual examination, tensile test, micro-Virkers hardness surveys of the bond of area and optical microstructure investigations for welded joint parts. Finally, post weld heat treatment(PWHT) of the high-frequency induction hardening was performed for the friction welded specimens under the optimal welding conditions. And then, the mechanical properties were compared for as-welded and PWHT in SM 45C to SF 45.
Life Prediction for High Pressure Hose of Power Steering System by Impulse Pressure Test
Lee, Gi-Chun ; Kim, Hyoung-Eui ; Park, Jong-Won ; Lee, Jong-Hwang ; Jeong, Won-Wook ; Im, Young-Han ; Hwang, Kwon-Tae ; Lee, Young-Shin ; Kim, Jae-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 91~96
DOI : 10.3795/KSME-A.2010.34.1.91
The hydraulic hose can be divided with the low pressure, the medium pressure, and the high pressure hose according to the applied pressure. The power steering system in a passenger car can be divided with the high pressure and the low pressure hose. This study deals with the life prediction for high pressure hose to be given impulse pressure which was generated in turning the car. To adjust with external and internal condition, impulse pressure and oil temperature need to be controlled with impulse test system. The result, which is only controlled with the pressure and oil temperature, adapted Calibrated Accelerated Life Test(CALT) method to predict the life of the high pressure hose and analyzed the swagging part by finite element method during the impulse test.
Analysis of Overlay Weld Effect on Preventing PWSCC in Dissimilar Metal Weld
Lee, Seung-Gun ; Oh, Chang-Kyun ; Park, Heung-Bae ; Jin, Tae-Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 97~101
DOI : 10.3795/KSME-A.2010.34.1.97
PWSCC(Primary Stress Corrosion Cracking) in Alloy 82/182 butt welds is the problem affecting safety and integrity of nuclear power plant. PWSCC can be occurred in the area that is at high magnitude of tensile residual stress, such as Alloy 82/182 dissimilar metal welds in PZR(pressurizer) nozzles. There have been a number of incidents recently at the dissimilar metal welds in overseas nuclear power plants. Overlay weld is the one of the effective methods to decrease tensile residual stress of inside surface, which will result in preventing PWSCC. In this paper, overlay weld conditions on the purpose of preventing PWSCC was explained and the benefit of the overlay weld was confirmed performing finite element analysis.
Development of Assessment Methodology on Creep-Fatigue Crack Behavior for a Grade 91 Steel Structure
Lee, Hyeong-Yeon ; Lee, Jae-Han ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 103~110
DOI : 10.3795/KSME-A.2010.34.1.103
In this study, an assessment method on creep-fatigue crack initiation and crack growth for a Mod.9Cr-1Mo steel (ASME Grade 91) structure has been developed with an extension of the French RCC-MR A16 procedure. The current A16 guide provides defect assessment procedure for a creep-fatigue crack initiation and crack growth for an austenitic stainless steel, but no guideline is available yet for a Mod.9Cr-1Mo steel which is now widely being adopted for structural materials of future nuclear reactor system as well as ultra super critical (USC) thermal plant. In the present study an assessment method on creep-fatigue crack initiation and crack growth is provided for the FMS (Ferritic-Martensitic Steel) and assessment on the creep-fatigue crack behavior for a structure has been carried out. The assessment results were compared with the observed images from a structural test.
Design Development Test of Crashworthiness Device for Landing Gear
Shin, Jeong-Woo ; Kim, Tae-Uk ; Hwang, In-Hee ; Jo, Jeong-Jun ; Lee, Jeong-Sun ; Park, Chong-Yeong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 111~116
DOI : 10.3795/KSME-A.2010.34.1.111
To improve occupants` safety in an emergency, crashworthy design is necessary to rotorcraft design and development. Especially, landing gear has the important role for crashworthy design because landing gear absorbs relatively large energy for the crash landing. In addition, military specifications require failure of landing gear shall not increase danger to any occupants by penetration of the airframe. To meet the specification requirements, crashworthiness device like failure mechanism should be prepared so that landing gear is collapsed safely and doesn`t penetrate the airframe. In this study, design and design development test of the failure mechanism which is necessary for the rotorcraft landing gear was performed. First, collapse scenario was determined for the landing gear not to penetrate the airframe. Then, the failure pin which is the most important part of the failure mechanism was designed with 2 strength range in order to meet design criteria. Finally, design of the failure mechanism was verified successfully by design development test.
Analytical Study for the Safety of the Bird Strike to the Small Aircraft Having a Composite Wing
Park, Ill-Kyung ; Kim, Seung-Jun ; Choe, Ik-Hyun ; An, Seok-Min ; Yeo, Chan-Hong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 1, 2010, Pages 117~124
DOI : 10.3795/KSME-A.2010.34.1.117
The bird strike to small aircraft has not been an issue because of its low speed and usage as a private aircraft. So, the compliance of the bird strike regulation is limited to large fixed-wing aircraft such as the commuter category in FAR Part 23 and the civil aircraft in FAR Part 25, generally. However, the forecast of dramatic increasing of VLJ(Very Light Jet), the usage of a composite material for an aircraft structure and flight time of general aviation due to Air-taxi for the point to point transportation, would rise up the need of bird strike regulations and a safety enhancement in normal and utility categorized aircraft. In this study, the safety of bird strike to small aircraft wing leading edge made of a metal and a composite material were compared using the explicit finite element analysis.