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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Manufacturing Technology Engineers
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Journal DOI :
The Korean Society of Manufacturing Technology Engineers
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Volume & Issues
Volume 23, Issue 6 - Dec 2014
Volume 23, Issue 5 - Oct 2014
Volume 23, Issue 4 - Aug 2014
Volume 23, Issue 3 - Jun 2014
Volume 23, Issue 2 - Apr 2014
Volume 23, Issue 1 - Feb 2014
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Safety Evaluation of a Cylinder Valve for Compressed Natural Gas Vehicle Pressure Vessels using Fluid-structure Interaction Analysis
Lee, Hyo Ryeol ; Ahn, Jung Hwan ; Kim, Bok Man ; Kim, Hwa Young ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 103~108
DOI : 10.7735/ksmte.2014.23.2.103
Growing concerns about environmental pollution have led to an increase in the demand for compressed natural gas (CNG) vehicles in recent years. CNG vehicles are equipped with a cylinder valve installed in a high-pressure vessel to control the CNG flow. The cylinder valve must meet high quality safety standards because the pressure vessel stores high-pressure CNG. Therefore, safety evaluation of the cylinder valve is necessary to ensure the safety of CNG vehicles. In this study, fluid-structure interaction analysis for the structural integrity of the cylinder valve were conducted using a commercial finite element analysis code(ANSYS WORKBENCH V14). The CFD analysis was performed using a steady-state technique according to the inlet and outlet pressures in order to predict the pressure distribution. Structural analysis was performed by a static structure technique at the maximum working pressure to evaluate the structural integrity of the cylinder valve. From the results, the safety factor of the valve component is between 1.57 and 21.5.
Gear Teeth Modification for a 2.5MW Wind Turbine Gearbox
Lee, Hyoung Woo ; Kang, Dong-Kwon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 109~117
DOI : 10.7735/ksmte.2014.23.2.109
This paper reports a method to modify the gear tooth profile of a wind turbine gearbox to reduce the noise caused by the impact of the gear teeth. The major causes of tooth impact are the elastic deformation of the gear teeth, shafts, and case of the gearbox under loading, and the fabrication tolerances in gear manufacturing. In this study, the tooth profile was modified considering the elastic deformation of the gear tooth and the tooth lead modification to compensate for tooth interference in the lead direction as a result of shaft deformations. The method was applied to the gearbox of a 2.5MW wind turbine, and the transmission error was characterized before and after modifying the gear teeth. For the modified gear teeth, the transmission error (67.6%) was lower by 17.8%. Additionally, the gear contact stress was reduced by 6.3%, to 22.3%.
Development and Evaluation of Stitching Algorithm With five Degrees of Freedom for Three-dimensional High-precision Texture of Large Surface
Lee, Dong-Hyeok ; Ahn, Jung-Hwa ; Cho, Nham Gyoo ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 118~126
DOI : 10.7735/ksmte.2014.23.2.118
In this paper, a new method is proposed for the five-degree-of-freedom precision alignment and stitching of three-dimensional surface-profile data sets. The control parameters for correcting thealignment error are calculated from the surface profile data for overlapped areas among the adjacent measuring areas by using the "least squares method" and "maximum lag position of cross correlation function." To ensure the alignment and stitching reliability, the relationships betweenthe alignment uncertainty, overlapped area, and signal-to-noise level of the measured profile data are investigated. Based on the results of this uncertainty analysis, an appropriate size is proposed for the overlapped area according to the specimen`s surface texture and noise level.
Effect of Molding Conditions on Demolding Force During Injection Molding of Parts with Micro-features
Park, S.H. ; Yoo, Y.E. ; Lee, W.I. ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 127~132
DOI : 10.7735/ksmte.2014.23.2.127
Micro/nano-injection molding is one of the main processing techniques for polymer micro-fabrication. Most of the difficulties encountered in polymer micro-molding are caused by the demolding, rather than the filling of molds. Therefore, studying the demolding process is vitally important for manufacturing polymer replicas. The most important parameters are the thermal stress, friction and adhesion forces, and mechanical strength of the resist. In this research, we determinedthe effects of the processing conditions on the ejection force for cases involving two common thermoplastic polymers. The results showed that the processing conditions noticeably influenced the ejection force.
Structural and Optical Characteristics of ChalcogenideGe_Sb_Se for Basic Aspheric Lens Design
Ko, Jun Bin ; Myung, Tae Sik ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 133~137
DOI : 10.7735/ksmte.2014.23.2.133
The recent development of electro-optic devices and anticorrosion media has made it necessary investigate infrared optical systems with solid-solid interfaces of materials with amorphous characteristics. One of the most promising classes of materials for these purposes seems to be chalcogenide glasses, which are based on the Ge_Sb_Se system, have drawn much attention because of their use in preparing optical lenses and fibers that are transparent in the range of 3-12 um. In this study, a standard melt-quenching technique was used to prepare amorphous Ge_Sb_Sechalcogenideto be used in the design and manufacture of infrared optical products. The results of structural, optical, and surface roughness analyses of high purity Ge_Sb_Sechalcogenide glasses after various annealing processes reported.
Air Resistance Due to the Deflector Configuration of Commonly Used Largetrucks
Han, Moonsik ; Cho, Jaeung ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 138~144
DOI : 10.7735/ksmte.2014.23.2.138
This study investigates the air resistance due to deflector configurations of commonly used largetrucksat a driving speedof 80 km/h. Of the 6 models that are considered, the drag causedby the pressure on the front part of the trailer is largest for model 1. For model 1, the lift caused by the difference between the velocities of the upper and lower streams isgreatest amongall the models. Model 6 has the least resistance against the flow stream consideringthedrags and lifts of theflow models. Anoptimal design can be obtainedby investigating thesimulation analysis ofvarious deflector configurationsfor the upper part of largetrucks; this optimum deflector configuration will help reduce the air resistanceon large trucks.
Development and Durability Evaluation of a Bimaterial Composite Frame by Pultrusion Process
Lee, Haksung ; Kang, Shinjae ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 145~151
DOI : 10.7735/ksmte.2014.23.2.145
Recently, the growing demand for weight reduction and improved structure durabilityfor commercial vehicles has led to active research into the development and application of suitablecomposite materials. This studysuggests abimaterial composite frame produced by apultrusion process to replace steel frames. We focused on the development of a composite frameconsisting of two types of materialsby mixing anorthotropic material with anisotropic material. The inside layer consisted of an aluminum pipe, and the outside layer was composed of a glass fiber pipe. To determine the strength and failure mechanisms of the composite material, tensile tests, shear tests, and three-point bending tests were conducted, followed by fatigue tests. After static testing, the fatigue tests were conducted at a load frequency of 5 Hz, a stress ratio (R) of 0.1, and an endurance limit of
for the S-N curve. The resultsshowed that the failure modes were related to both the core design and the laminating conditions.
Sintering and Heat Treatment Characteristics of Al-Cu-Mg Powder Metallurgy Alloy for Lightweight Automotive Parts
Ahn, Byungmin ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 152~156
DOI : 10.7735/ksmte.2014.23.2.152
Lightweight materials such as aluminum and magnesium have recently received much attention in the automotive industries because of environmental and fuel-efficiency concerns. Using the powder metallurgy (PM) process for these materials creates significant opportunities for the cost-effective manufacture of lightweight automotive parts. In the present study, an Al-Cu-Mg alloy was fabricated using conventional PM processes. Primarily, the effects of the alloying elements on the sintering characteristics and mechanical behavior after heat treatment were investigated. A microstructural analysis was performed using an optical microscope and a scanning electron microscope to investigate the behavior of liquid phase sintering, including the formation of precipitates. The dependence of the mechanical behavior on the alloying elements was evaluated based on the transverse rupture strength.
Robust Adaptive Control of Hydraulic Positioning System Considering Frequency Domain Performance
Kim, Ki-Bum ; Kim, In-Soo ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 157~163
DOI : 10.7735/ksmte.2014.23.2.157
In this paper, a robust MRAC (model reference adaptive control) scheme is applied to control an electrohydraulic positioning system under various loads. The inverse dead-zone compensator in the control system cancels out the dead-zone response, and an integrator added to the controller provides good position-tracking ability. LQG/LTR (linear quadratic Gaussian control with loop transfer recovery) closed-loop model is used as the reference model for learning the MRAC system. LQG/LTR provides a systematic technique to design the linear controller that optimizes the objective function using some compromise between the control effort and the system performance in the frequency domain. Different external load tests are performed to investigate the effectiveness of the designed MRAC system in real time. The experimental results show that the tracking performance of the proposed system is highly accurate, which offers considerable robustness even with a large change in the load.
Stiffness Analysis of Planar Parallel Manipulators with Serially Connected Legs
Kim, Han Sung ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 164~172
DOI : 10.7735/ksmte.2014.23.2.164
This paper presents a method for analyzing the stiffness of full and low DOF (degree of freedom) planar parallel manipulators with serially connected legs. The individual stiffness of each leg is obtained by applying reciprocal screws to the leg twist using passive joints and elastic elements consisting of actuators and links. Because the legs are connected in parallel, the manipulator stiffness is determined by summing the individual leg stiffness values. This method does not require the assumption that springs should be located along reciprocal screws and is applicable to a planar parallel manipulator with a generic or singular configuration. The stiffness values of three planar parallel manipulators with different DOFs are analyzed. The numerical results are confirmed using ADAMS S/W.
Area of Horn`s Tip and Weldability of Cu Sheets
Jang, Ho Su ; Kang, Eun Ji ; Park, Dong Sam ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 173~177
DOI : 10.7735/ksmte.2014.23.2.173
In this study, a 20,000Hz ultrasonic horn was designed and fabricated using a finite element analysis. The horn`s resonate frequency was 19,991Hz, and the harmonic response frequency was 20,000Hz. In order to observe the developed horn`s performance, 4,000 pieces of displacement data were obtained using an optical sensor and were analyzed using a fast Fourier transform. Finally, the developed horn`s resonate frequency was found to be 19,992Hz. The effect of the tip area of the developed horn on the weldability of a Cu sheet was experimentally investigated. It was found that the welding strengths of specimens welded using a small tip area were generally higherthan those of specimens welded using a large tip area.
Fabrication of a Multiplexing Sensor Probe for Measuring the Blade Deflection of a Wind Power Generator
Kim, Ji-Dea ; Lee, Dong-Ju ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 178~185
DOI : 10.7735/ksmte.2014.23.2.178
This paper describes a fabrication multiplexing sensor probe that employs a fiber Bragg grating(FBG) based on multiple measurements to determine the blade deflection of a wind power generator the reliability analysis of this probe is also presented. To diminish the temperature sensitivity of the FBG sensor, we form multiple CFRPs onto the upper and lower layers of the FBG and package it with an epoxy resin. As a result, the depth of the CFRP is 1mm, and the temperature sensitivity is
. We construct a sensor network utilizing the fabricated sensor with a blade beam model. As the number of pendulums is increased on the fore-end of the beam, the strain value is measured. The strain variation is calculated from the measurement of the load on the blade beam model by monitoring the strain of the FBG sensor. When the linear equation is applied, the strain error is 0.4% and when the finite difference method is used, the tip deflection error is 3.3%. The displacement error derived from the strain value of the FBG sensor is 4.39%. The calculated result between the measured value of the dead-end of the beam and the strain is less than 2.46% tip distortion error. Therefore, our proposed multiplexing sensor probe is a low-cost and high-reliability solution for a commercial wind power generator.
Characteristic Analysis of Underwater Bearing for Canned-Type Electric Water Pump
Park, In Kyum ; Kim, Hyung Jin ; Hong, Nam Pyo ; Seo, Young Ho ; Kim, Byeong Hee ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 186~193
DOI : 10.7735/ksmte.2014.23.2.186
This paper presents characteristic analysis of underwater bearing for canned type electric water pump. Characteristic analysis of underwater bearing was performed using self-developed performance tester, which capable of torque change, noise change, motor speed change and abrasion loss test with respect to temperature change of underwater bearing. The performance tester can be monitored in real time by designing the control unit using the Labview program. The performance experiment was performed through comparison of the silicon carbide (SIC) and the carbon bearing. From the experiment results, performance of SIC bearing was better than carbon bearing at the abrasion and temperature experiment.
Roller Track Gear System Design based on Roller Gear Mechanism
Kwon, Soon-Man ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 194~198
DOI : 10.7735/ksmte.2014.23.2.194
In recent years, RGM(roller gear mechanism) systems, wherein one of the gears of a meshing gear pair is replaced with pins or rollers, have been reintroduced, which is a consequence of, and therefore a reflection of, the rapid advances made in manufacturing technology. Three RTG(roller track gear) systems for arbitrary path transportation (e.g., L-, O-, U-, and S-shaped tracks) were constructed using two out of three RGM systems, namely, the CRP(cam rack pinion), CRG(cam ring gear), and RPG(roller pinion gear) systems, and are introduced in this paper. We also present three ways to prevent the intersection and non-contact phenomena at the teeth in the vicinity of the conversion point between two joined RGM systems.
Implementation of an Interrogator for the Operationand Measurement of Fiber Bragg Grating Multiplexing Sensor Probes
Kim, Ji-Dea ; Lee, Dong-Ju ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 199~205
DOI : 10.7735/ksmte.2014.23.2.199
This research focuses on the development of an interrogator that operates and measures fiber Bragg grating(FBG) multiplexing sensor probes for accurate-measurement of the blade deflection in a wind power generator. We designed and fabricated an optical source and spectrum module for the interrogator. Additionally, we verified the wavelength repeatability within 0.001 nm and the wavelength stability within 1 pm of the optical source, and we experimentally determined that the wavelength scanning range was about 44.4 nm. The FBG sensor with 2 nm resolution can be extended to a performance-efficient system that measures more than 20 sensors. The implemented interrogator has 0.141 nm wavelength variations corresponding to an ambient temperature range of
. The measurement error can be easily reduced by employing a temperature compensation algorithm. In this study, we quantitatively confirmed the accuracy and operating stability of the interrogator.
Effects of Variation in Process Parameters on Cavity Pressure and Mechanical Strength of Molded Parts in LSR Injection Molding
Park, Hyung Pil ; Cha, Baeg Soon ; Lee, Jeong Won ; Ko, Young Bae ; Kim, Sang Gweon ; Jung, Tae Sung ; Kim, Dong Han ; Rhee, Byung Ohk ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 2, 2014, Pages 206~212
DOI : 10.7735/ksmte.2014.23.2.206
Liquid silicone rubber (LSR) has been widely used in automotive, electrical, and medical components. Thus, research on the use of LSR in the injection molding process is required to obtain high-quality and high-performance products. In this study, a mold was fabricated to examine the effects of the process parameters on the molding and mechanical properties of LSR parts. A computer-aided engineering analysis was used to optimize the air vent depth and curing temperature to decrease the flash at the air vents caused by the low viscosity of LSR. Temperature and pressure sensors were mounted in the mold to determine the effects of the process parameters on the temperature and pressure in the cavity. The tensile strength of the LSR parts was also examined in relation to the process parameters.