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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
Editor in Chief :
Volume & Issues
Volume 40, Issue 9 - Sep 2016
Volume 40, Issue 8 - Aug 2016
Volume 40, Issue 7 - Jul 2016
Volume 40, Issue 6 - Jun 2016
Volume 40, Issue 5 - May 2016
Volume 40, Issue 4 - Apr 2016
Volume 40, Issue 3 - Mar 2016
Volume 40, Issue 2 - Feb 2016
Volume 40, Issue 1 - Jan 2016
Selecting the target year
Experimental Study for the Reinforcement of District Heating Pipe
Kim, Jaemin ; Kim, Jooyong ; Cho, Chongdu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 245~252
DOI : 10.3795/KSME-A.2016.40.3.245
In this study, an alternative bend design is proposed to overcome the aging problem in piping bends. In this design, the foam pad is not included. Finite element analysis was performed based on the total pipe diameter. From this analysis, the shape of the Shear Control Ring (SCR) was determined. Temperature, stress, and other data of the proposed reinforced pipe were acquired and analyzed after the test was performed. The value of the thermal stress for the reinforced steel pipe satisfied the required standard without the foam pad based on the manufacturing of the reinforced fitting and construction site of the test. The reinforcement provided a shear strength level for the foam pad that resulted in maximum shear stress less than stress based on the original foam pad applied at the pipe bend. Additionally, an increasing factor of safety effect for the reinforced fitting application was discovered.
Wedge Splitting Test and Fracture Energy on Particulate Reinforced Composites
Na, Seong Hyeon ; Kim, Jae Hoon ; Choi, Hoon Seok ; Park, Jae Beom ; Kim, Shin Hoe ; Jung, Gyoo Dong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 253~258
DOI : 10.3795/KSME-A.2016.40.3.253
The effect of temperature on the fracture energy, crack propagation, and crack tip opening displacement (CTOD) was determined for particulate reinforced composites using the wedge splitting test. The materials that were used consisted of a polymer binder, an oxidizing agent, and aluminum particles. The test rate of the wedge splitting specimen was 50 mm/min, the temperature conditions were
, room temperature,
. The fracture energy, calculated from splitting load-crack mouth opening displacement(CMOD) curves, increased with decreasing temperature from
. In addition, the strength of the particulate reinforced composites increased sharply at
, and the composites evidenced brittle fracture due to the glass transition temperature. The strain fields near the crack tip were analyzed using digital image correlation.
Verification Study of Lifetime Prediction Models for Pb-Based and Pb-Free Solders Used in Chip Resistor Assemblies Under Thermal Cycling
Han, Changwoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 259~265
DOI : 10.3795/KSME-A.2016.40.3.259
Recently, life prediction models for Pb-based and Pb-free solders used in chip resistor assemblies under thermal cycling have been introduced. The models suggest that the field lifetimes of Pb-free solders would be better than those of Pb-based solders when used for chip resistors under thermal cycling conditions, while the lifetime of the chip assemblies under accelerated test conditions show a reverse relationship. In this study, the prediction models were verified by applying the model to another research case. Finite element models were built, thermal cycling conditions were applied, and the energy densities were calculated. Finally, life prediction analysis was conducted for the cases where Pb-based and Pb-free solders were used. The prediction results were then compared with the test data of the case. It was verified that the predictions of the developed life cycle models are on the practical scale.
Mechanical Characteristics and Crack-Healing of ZIRCONIA(ZrO
) Composite Ceramics with SiC and TiO
Nam, Ki Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 267~273
DOI : 10.3795/KSME-A.2016.40.3.267
This study evaluated the mechanical properties and crack-healing abilities of zirconia composite ceramics. The six kinds of specimens used were: partially stabilized zirconia (Z) and five zirconia composite (ZS, ZST1, ZST2, ZST3, and ZST5) with SiC and
. There was not a large difference between the Vickers hardness of the six types of zirconia ceramics. The bending strength of the ZS specimen degraded rapidly, but the zirconia specimens with
(ZST1, ZST2, ZST3, and ZST5) showed improved strength. Therefore, it was determined that the bending strength is affected by the crystallization, which is due to the addition of SiC and
. From the crack-healing conditions having the highest bending strength, monolithic zirconia retained its cracks, while the specimens of four types with SiC healed their cracks.
Optimum Design of a Coil Spring for Improving the Performance of a Spring -Operated Mechanism
Lee, Dae Woo ; Sohn, Jeong Hyun ; Yoo, Wan Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 275~280
DOI : 10.3795/KSME-A.2016.40.3.275
In this study, a release test bed is designed to evaluate the dynamic behaviors of a coil spring. From the release tests, the dynamic behaviors of a coil spring are analyzed. A lumped parameter spring model was established for numerical simulation of a spring. The design variables of a coil spring are optimized by using the design of experiments approach. Two-level factorial designs are used for the design optimization, and the primary effects of the design variables are analyzed. Based on the results of the interaction analysis and design sensitivity analysis, the level of the design variables is rearranged. Finally, the mixed-level factorial design is used for the optimum design process. According to the optimum design of the opening spring, the dynamic performance of the spring-operated mechanism increases by 2.90.
Test and Numerical Analysis for Penetration Residual Velocity of Bullet Considering Failure Strain Uncertainty of Composite Plates
Cha, Myungseok ; Lee, Minhyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 281~288
DOI : 10.3795/KSME-A.2016.40.3.281
The ballistic performance data of composite materials is distributed due to material inhomogeneity. In this paper, the uncertainty in residual velocity is obtained experimentally, and a method of predicting it is established numerically for the high-speed impact of a bullet into laminated composites. First, the failure strain distribution was obtained by conducting a tensile test using 10 specimens. Next, a ballistic impact test was carried out for the impact of a fragment-simulating projectile (FSP) bullet with 4ply ([0/90]s) and 8ply ([0/90/0/90]s) glass fiber reinforced plastic (GFRP) plates. Eighteen shots were made at the same impact velocity and the residual velocities were obtained. Finally, simulations were conducted to predict the residual velocities by using the failure strain distributions that were obtained from the tensile test. For this simulation, two impact velocities were chosen at 411.7m/s (4ply) and 592.5m/s (8ply). The simulation results show that the predicted residual velocities are in close agreement with test results. Additionally, the modeling of a composite plate with layered solid elements requires less calculation time than modeling with solid elements.
Kinematics of an Intrinsic Continuum Robot with Pneumatic Artificial Muscles
Kang, Bong Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 289~296
DOI : 10.3795/KSME-A.2016.40.3.289
This study presents the kinematics of an intrinsic continuum robot actuated by pneumatic artificial muscles. The single section of a developed continuum robot consisted of three muscles in parallel. The contraction of each muscle according to applied air pressure produced spatial motions of a distal plate with respect to a base plate. Based on the bending behaviors of artificial muscles, the orientation and position of the end-effector of a continuum robot were formulated using a transformation matrix. The orientation and position was also determined for a single section of the distal plate. A Jacobian matrix relating the contraction rate or the pressure rate of the muscles to the velocity vector of the end-effector was calculated considering the assembled position of actuators between neighboring sections of the robot. Experimental results showed that the motions of the intrinsic continuum robot were accurately estimated by the proposed kinematics.
Evaluation of Ballistic Performance of Ceramic-Tile-Inserted Metal Block
Lee, Seunghwan ; Lee, Minhyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 297~304
DOI : 10.3795/KSME-A.2016.40.3.297
A numerical simulation has been performed for the penetration of a long-rod penetrator into a metal block (ceramic-tile-inserted 4340-steel plate). The impact velocity is 1.5km/s at a normal incidence angle. The first two validations are conducted for a semi-infinite block measuring the depth of penetration (DOP). The material model of ceramic is the JH-2 (Johnson-Holmquist) model. The predicted DOP values are in close agreement with the experimental data. Then, the primary simulation is performed by varying the position of the confined ceramic tile for three types of thickness of ceramic tile. The residual velocity, residual mass and residual kinetic energy of the long-rod are obtained from the simulation. Based on these predicted values, the trend of the ballistic performance of the protective structure is estimated. In addition, the mass efficiency is calculated in order to determine the performance of the ceramic-tile-inserted metal block. Finally, the optimum protective structure is identified.
A Study on the Development of a Robot Vision Control Scheme Based on the Newton-Raphson Method for the Uncertainty of Circumstance
Jang, Min Woo ; Jang, Wan Shik ; Hong, Sung Mun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 305~315
DOI : 10.3795/KSME-A.2016.40.3.305
This study aims to develop a robot vision control scheme using the Newton-Raphson (N-R) method for the uncertainty of circumstance caused by the appearance of obstacles during robot movement. The vision system model used for this study involves six camera parameters (C1-C6). First, the estimation scheme for the six camera parameters is developed. Then, based on the six estimated parameters for three of the cameras, a scheme for the robot`s joint angles is developed for the placement of a slender bar. For the placement of a slender bar for the uncertainty of circumstances, in particular, the discontinuous robot trajectory caused by obstacles is divided into three obstacle regions: the beginning region, middle region, and near-target region. Then, the effects of obstacles while using the proposed robot vision control scheme are investigated in each obstacle region by performing experiments with the placement of the slender bar.
A Study on Suspension Optimization of the Korean Personal Rapid Transit Vehicle
Kim, Hyun Tae ; Kim, Jun Woo ; Cho, Jeong Gil ; Koo, Jeong Seo ; Kang, Seokwon ; Jeong, Raggyo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 317~326
DOI : 10.3795/KSME-A.2016.40.3.317
In this study, running stability and ride quality analyses, applying the `ISO 3888 (double lane change)` and `ISO 2631-1` (mechanical vibration and shock) tests, were performed for the suspension optimization of the Korean personal rapid transit (PRT) vehicle. The suspension optimization results for running stability and ride quality were derived by applying the multiresponse surface method. From the comparisons of the optimization results for different ratios of the objective functions of running stability and ride quality, we derived the best objective function ratio of 3.9-to-6.1 to improve both the running stability and the ride quality. With the optimized results, the suspension stiffness became 30.68 N/mm, between the value of the
models, and the damping coefficient equaled that of the
model. When compared with the suspension of the current PRT vehicle, the roll angle, yaw rate, sideslip angle, and ride comfort were improved by 0.37, 0.37, 2.8, and 5, respectively.
A Fast Generation Method of CAM Model for Machining of Jet Engines Using Shape Search
Kim, Byung Chul ; Song, Ilhwan ; Shin, Suchul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 3, 2016, Pages 327~336
DOI : 10.3795/KSME-A.2016.40.3.327
Manufacturers of aircraft engines have introduced computer-aided manufacturing (CAM) software to operate and control computerized numerical control (CNC) machine tools. However, the generation of a CAM model is a time consuming and error-prone task since machining procedure and operational details are manually defined. For the automatic generation of a CAM model, feature recognition techniques have been widely studied. However, their recognition coverage is limited so that complex shapes such as a jet engine cannot be fully developed. This study presents a novel approach to quickly generate a CAM model from a CAD model using shape search techniques. Once an operator sets a machining operation as a reference operation, the same shapes as the shapes referenced by the operation are searched. The reference operation is copied to the positions of the searched shapes. The proposed method was verified through experiments with a jet engine compressor case.