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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
Forensic Engineering Study on Damage Assessment of the Damage to the Internal Parts of a Vehicle Involved in a Fire Accident
Kim, Eui-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 255~261
DOI : 10.3795/KSME-A.2010.34.3.255
Forensic engineering is the area of expertise of those qualified to serve as engineering experts in courts of law or arbitration proceedings. Especially failure of internal parts during vehicle fire accidents causing injuries and damage to property almost always generates conflict between the automaker and customer. Hence, the investigation of such events generally involves an engineering analysis. One of the possible reasons for such accidents caused by vehicle fire is the failure of the piston and connecting rod. By formal inspections and engineering tests, this study shows the results of investigation and the cause of failure of the mechanical parts. For this purpose the failure mechanism is analyzed by using fractography methods and by applying an instrumented indentation technique to compare the material properties of the reference part with those of the malfunctioning part.
Influence of Micro Pattern Geometry and Printing and Curing Conditions in Gravure Printing on Printing Performance When Using Conductive Ink
Ahn, Byoung-Joon ; Han, Kyung-Joon ; Ko, Sung-Lim ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 263~271
DOI : 10.3795/KSME-A.2010.34.3.263
e-Printing is a new manufacturing technology for electronic products and is based on traditional printing technology. The electronic products require a large area to facilitate printing and to be economical. A gravure printing system that supports a roll to roll (R2R) manufacturing process can be used to reduce the cost and to achieve the required accuracy. Many factors such as drying method, drying temperature, tension,-printing velocity, ink viscosity, ink conductivity, pattern accuracy, and dot geometry influence the performance of printed electronics. These factors are closely interrelated. The optimum condition for printing must be determined to enhance the performance of the printed electronics. In this study, lines and areas are printed using a gravure printer with conductive ink under different conditions of the above mentioned factors. The results are analyzed to investigate the influence of various factors on the performance of the printed electronics.
Lifetime Estimation of an Axle Drive Shaft by Calibrated Accelerated Life Test Method
Kim, Do-Sik ; Kim, Hyoung-Eui ; Yoon, Sung-Han ; Kang, E-Sok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 273~281
DOI : 10.3795/KSME-A.2010.34.3.273
In this paper, a method to predict the fatigue life of an axle drive shaft by the calibrated accelerated life test (CALT) method is proposed. The CALT method is very effective for predicting lifetimes, significantly reducing test time, and quantifying reliability. The fatigue test is performed by considering two high stress and one low stress levels, and the lifetime at the normal stress level is predicted by extrapolation. In addition, in this study, the major reliability parameters such as the lifetime, accelerated power index, shape parameter, and scale parameter are determined by conducting various experiments. The lifetime prediction of the axle drive shaft is verified by comparing the experimental results with load spectrum data. The results confirm that the CALT method is effective for lifetime prediction and requires a short test time.
Optimal Design of Magnetically Levitated Flywheel Energy Storage System Based on System Stability Using Rigid-Body Model
Kim, Jung-Wan ; Yoo, Seong-Yeol ; Bae, Yong-Chae ; Noh, Myoung-Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 283~289
DOI : 10.3795/KSME-A.2010.34.3.283
Owing to the increasing worldwide interest in green technology and renewable energy sources, flywheel energy storage systems (FESSs) are gaining importance as a viable alternative to traditional battery systems. Since the energy storage capacity of an FESS is proportional to the principal mass-moment of inertia and the square of the running speed, a design that maximizes the principal inertia while operatingrunning at the highest possible speed is important. However, the requirements for the stability of the system may impose a constraint on the optimal design. In this paper, an optimal design of an FESS that not only maximizes the energy capacity but also satisfies the requirements for system stability and reduces the sensitivity to external disturbances is proposed. Cross feedback control in combination with a conventional proportional-derivative (PD) controller is essential to reduce the effect of gyroscopic coupling and to increase the stored energy and the specific energy density.
Design and Performance Evaluation of Dimpled EGR Cooler
Seo, Young-Ho ; Lee, Hyun-Min ; Heo, Seong-Chan ; Ku, Tae-Wan ; Song, Woo-Jin ; Kang, Beom-Soo ; Kim, Jeong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 291~298
DOI : 10.3795/KSME-A.2010.34.3.291
A conventional EGR cooler, which is used in an EGR system of an automobile diesel engine, has a low heat-exchange efficiency. To maximize the heat transfer between the exhaust gas and coolant, dimples are formed on the surface of heat exchange tubes. When designing the dimpled EGR cooler, the net heat transfer areas in the conventional and dimpled tube-type EGR coolers are compared. Structural integrity evaluations are also performed by combining finite element analysis with a homogenization method. Subsequently, the process of manufacturing the dimpled tube, i.e., the formation of dimples, edge bending, center v-notch bending, compression, and plasma welding, is established and carried out. Thus, the dimpled EGR cooler is developed, and its performance is verified.
Study of Flexible Forming Process Involving the Use of Sectional Flexible Die for Sheet Material
Heo, Seong-Chan ; Ku, Tae-Wan ; Song, Woo-Jin ; Kim, Jeong ; Kang, Beom-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 299~305
DOI : 10.3795/KSME-A.2010.34.3.299
In general, the flexible forming die that has been used in the flexible forming process has the identical punch size; hence, its flexibility is relatively low because the range of allowable curvature radii is limited due to the uniform punch tip radius. Hence, a conceptual design of a sectional flexible die is presented for enhancing the flexibility of the forming process. Two punches of different sizes are used to configure the arbitrary forming surface. For a forming region with a relatively large curvature radius, a large punch array block is used; on the other hand, for the forming regions with small curvature radii, a small punch block is used. The cross-sectional profiles are compared with the target shape for evaluating the effectiveness of the process. Consequently, it is confirmed that the sectional flexible die can be used along with a combination of punch blocks of different sizes for manufacturing objective surfaces of complex shapes.
Shape Design of Bends in District Heating Pipe System by Taguchi Method
Choi, Moon-Deok ; Kim, Joo-Yong ; Ko, Hyun-Il ; Cho, Chong-Du ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 307~313
DOI : 10.3795/KSME-A.2010.34.3.307
In this study, alternative designs for the bends used in district heating pipes are investigated. The district heating pipes, which are subjected to temperatures of 10 to
and a water pressure of
, have to withstand thermomechanical cyclic loads when in use. These pipes comprise three concentric tubes: a steel pipe (internal), polyurethane (PUR) insulator (middle), and a high-density polyethylene (HDPE) case (external). In addition, the bends in the district heating pipe system are covered with foam pads that cause aging. In this study, an alternative bend design that does not involve the use of a foam pad is proposed to overcome the aging problem in the bends. In the proposed design, "shear rings" are added to the surface of a bend, and its dimensions are determined by a combination of the statistical (Taguchi) method and FEM. The geometrical parameters such as thickness, height, and number of the rings significantly affect the design optimization, and hence, they affect the results of the FEM.
Effects of Corrosion Behavior on Failure of Co-Cured Single Lap Joints Subjected to Cyclic Tensile Loads
Shin, Kum-Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 315~321
DOI : 10.3795/KSME-A.2010.34.3.315
Co-cured single lap joints under cyclic tensile loads fail initially at the tip of the interface corner between the two adherents. The failure mechanism is complex because it is related to corrosion fatigue. Corrosion behavior at the interface affects the failure of the joints because corrosion deteriorates fatigue resistance. In this study, we clarified the cause of interfacial corrosion in co-cured single lap joints under cyclic tensile loads. The failure mechanism was also analyzed by observing the failed surfaces of specimens and the stress distribution along the interface. The surface roughness at the interface and the stacking sequence of the composite adherent were examined to investigate their effects on failure of the joint.
3D FE Model with FEA Factors and Plastic Shots for Residual Stress Under Oblique Shot Peening
Lee, Bae-Hwa ; Kim, Tae-Hyung ; Lee, Hyung-Yil ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 323~331
DOI : 10.3795/KSME-A.2010.34.3.323
In this study, we propose a 3D finite element (FE) model for the residual stress under oblique shot peening. Using the FE model for an oblique impact, we examine the effects of factors on the residual stress such as the Rayleigh damping in the material, dynamic friction, and the rate dependency of the material and systematically integrate the effects. The plastic deformation of the shot is also emphasized. Then, the FE model is used to study oblique multi-impacts. The results obtained using the FE model are compared with experimental x-ray diffraction (XRD) results; in contrast to the rigid and elastic shots, plastic shots are found to produce residual stresses similar to that shown in the XRD results. Thus, the 3D FE models with integrated factors and plastically deformable shots are validated. The proposed model will serve as a basis for the 3D FE model for multi-impacts with different impact angles to simulate the actual phenomenon of shot peening.
Evaluation of Mechanical Properties of Alloy 82/182 Weld Joint Between SA508 Gr.3 Nozzle and F316L Safe-End
Kim, Jin-Weon ; Lee, Kyung-Soo ; Park, Chi-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 333~340
DOI : 10.3795/KSME-A.2010.34.3.333
This paper presents the distributions of the tensile and fracture properties of an alloy 82/182 dissimilar weld joint between an SA508 Gr.3 nozzle and F316L SS safe-end at ambient temperature. Tensile and J-R tests were conducted using specimens extracted from base metals, heat-affected zones (HAZs), buttering regions, and various regions of the weld metal. The results show that the root region of the weld has higher strength than the upper region. The yield and tensile strengths vary considerably within the root region of the weld. The buttering region had the lowest strengths. The strengths gradually increased as the F316L stainless steel weld boundary was approached. The variation of the strengths within the upper region of the weld is insignificant. The fracture toughness of the alloy 82/182 weld metal is less than those of both the base metals and both HAZs. Within the alloy 82/182 weld, the center of weld has a slightly lower fracture toughness than the weld boundary and buttering region, and the root region has greater toughness than the upper region of the weld.
Effect of Specimen Geometry on Bending and Tensile Strength of Material Used in Dissimilar Joints
Hur, Jang-Wook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 341~346
DOI : 10.3795/KSME-A.2010.34.3.341
The effect of specimen geometry on the bending and tensile strengths of dissimilar joints (
) with copper interlayers was evaluated. The average bending strength of specimens with circular cross sections was higher than that of specimens with rectangular cross sections. The crack initiation stress (
) was successfully determined by the acoustic emission (AE) method and was approximately 60~80% of the bending strength. The residual stresses near the interfaces on the ceramic side were measured by X-ray diffraction before conducting the bending test. The bending strength and the crack initiation stress decreased with an increase in the residual stresses. The effect of the bending strain component was evaluated by the tensile testing; the tensile strength decreased with an increase in the bending strain component and was approximately 80% of the bending strength.
Prediction of the Unwinding Performance of Optical Fiber Cables by Nonlinear Dynamics Analysis
Lee, Jae-Wook ; Kim, Kun-Woo ; Kim, Hyung-Ryul ; Yoo, Wan-Suk ; An, Deuk-Man ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 347~352
DOI : 10.3795/KSME-A.2010.34.3.347
Under harsh environments in which remote control is impossible, wire-guided control technology is effective for controlling distant underwater vehicles that serve mother ships in missions, such as exploration and installation. When the fiber is unwound from the spool, tension fluctuations occur in the fiber because of the relative velocity of the moving vehicles and unwinding velocity of the fiber. As a result, fiber cables exhibit complicated behaviors, become entangled, and may get cut. In this study, a spool-like design for winding tens of kilometers of fiber cables is proposed by analyzing cable winding. The unwinding performance of the designed spool is estimated by performing nonlinear dynamics analysis of the nonlinear behavior and tension fluctuations observed during the unwinding of the fiber.
Optimal Design of Lightweight Frame for Heavy Flat-Bed Trailer by Using Taguchi Method
Kim, Jin-Gon ; Yoon, Min-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 353~359
DOI : 10.3795/KSME-A.2010.34.3.353
For achieving economical fuel consumption, an increase in the load bearing capacity, and for environmental conservation, there is a constant demand for lightweight frames of commercial vehicles used in the transportation industry. In this study, a structural analysis of the frame of a heavy flat-bed trailer was performed to determine the optimal design of a new lightweight frame made of high-strength steel. To identify the key design parameters of the trailer frame, Taguchi's orthogonal array was used in the experiments. Using ANSYS, a commercial FEA program, the frame structure was optimized with respect to stress, deflection, and torsional stiffness by performing stress and vibration analyses. A physical model of the trailer was also built to verify the validity of the numerical analyses. Finally, an on-road fatigue test of the new lightweight frame made of the high-strength steel, ATOS80, was performed to confirm the durability of the new design.
Study of Factor Causing Wear of a Barrel Cam in a Paper-Cup-Forming Machine by Using Multibody Dynamics Model
Jun, Kab-Jin ; Park, Tae-Won ; Cheong, Kwang-Yeil ; Kim, Young-Guk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 361~367
DOI : 10.3795/KSME-A.2010.34.3.361
The barrel cam, which is a type of cylindrical cam, has been widely used as a part of index drive units for automatic manufacturing machines. The axis of rotation of the barrel cam is orthogonal to the axis of rotation of the follower. The index drive rotates or dwells depending on the cam profile, while the cam rotates with a constant velocity. Continuous sliding contact between the barrel cam and the follower surfaces causes wearing of the adhesive between them. This study shows that the contact force between two sliding bodies is responsible for the wear of the barrel cam in the paper-cup-forming machine. This contact force is calculated by using the multibody dynamics model of the paper-cup-forming machine. The analytical result is validated by comparing it to the actual wear spots on the real product.
Position Control of Linear Motor by Using Enhanced Cross-Coupling Algorithm
Han, Sang-Oh ; Huh, Kun-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 369~374
DOI : 10.3795/KSME-A.2010.34.3.369
Linear motors are easily affected by load disturbances, force ripples, friction, and parameter variations because there are no mechanical transmissions that can reduce the effects of model uncertainties and external disturbance. In this study, a nonlinear adaptive controller to achieve high-speed/high-accuracy position control of a two-axis linear motor is designed. The operation of this controller is based on a cross-coupling algorithm. Nonlinear effects such as friction and force ripples are estimated and compensated for. An enhanced cross-coupling algorithm is proposed for effectively improving the biaxial contour accuracy while achieving closed-loop stability. The proposed controller is evaluated by performing computer simulations.
Prediction of Residual Stress Caused by IML Process and Deformation Due to Thermal Impact
Lee, Jae-Won ; Jang, Eu-Gene ; Shin, Seung-Won ; Park, Seung-Ho ; Chung, Ha-Seung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 3, 2010, Pages 375~382
DOI : 10.3795/KSME-A.2010.34.3.375
In this study, we developed a method to predict the residual stress distribution and thermal deformation caused by in-mold labeling (IML) processes. IML is one of the injection molding processes for injecting a material into a cavity and subsequently inserting a decorated film. The IML process can yield products with decorations of outstanding excellent quality in only one working step. Although the IML process has various advantages, it causes defects such as film delamination, wash-out, and flow marks. In particular, deformation is considered to be a major concern in terms of delamination. To validate the model, the deformation predicted by using a numerical model was compared with experimental results, and both results showed good agreement. We verified that the developed method can be used to obtain the design guidelines for preventing delamination in the initial design stage of the IML process.