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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 21, Issue 6 - Dec 2012
Volume 21, Issue 5 - Oct 2012
Volume 21, Issue 4 - Aug 2012
Volume 21, Issue 3 - Jun 2012
Volume 21, Issue 2 - Apr 2012
Volume 21, Issue 1 - Feb 2012
Selecting the target year
Structural Analysis of Engine Mounting Bracket
Han, Moon-Sik ; Cho, Jae-Ung ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 525~531
DOI : 10.7735/ksmte.2012.21.4.525
This study aims at the structural analysis of vibration and fatigue according to the configuration of engine mount. Maximum equivalent stress or deformation is shown at bracket or case respectively. As harmonic vibration analysis, the maximum displacement amplitude is happened at 4,000Hz. Among the cases of nonuniform fatigue loads, `SAE bracket history` with the severest change of load becomes most unstable but `Sample history` or `Saw tooth` becomes most stable. In case of `Sample history` or `Saw tooth` with the average stress of 4,200MPa or 0MPa and the amplitude stress of -3,000MPa or 7MPa, the possibility of maximum damage becomes 70%. This stress state can be shown with 7 times more than the damage possibility of `SAE bracket history` or `SAE transmission`. The structural result of this study can be effectively utilized with the design on engine mount by investigating prevention and durability against its damage.
A Study on the Mechanical Properties of Butt Welding Zone of Clad Steel According to the Process Design
Lee, Jung-Hyun ; Park, Jae-Won ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 532~540
DOI : 10.7735/ksmte.2012.21.4.532
In this study, some considerations have been suggested in developing on-site techniques to evaluate the sensitization of stainless steels. Electrochemical potentiokinetic reactivation (EPR) technique is known to be a candidate tool for field applications since it enables quantitative assessment in reasonable test time, compared to oxalic etching (ditch) technique. The on-site application of the test method imposes additional restrictions on the selection of the test method (for example, minimum surface preparation requirement, insensitivity to testing temperature, etc.). The EPR and etching techniques have been compared in order to sensitization of stainless steel structures. It has been widely reported that the maximum sensitivity in the welded structure of stainless steel is shown at heat-affected zone (HAZ) than weldments with cast structure. In this work, sectioned weldments and external surfaces were investigated to reveal the degree of sensitization by the etching and the results were compared with those of EPR test. The EPR test showed little sensitivity to surface roughness and test temperature.
A Study on Oil`s Contamination Detection System using Optical Fiber Sensor
Song, Doo-Sang ; Hong, Jun-Hee ; Ryu, Sang-Hyun ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 541~546
DOI : 10.7735/ksmte.2012.21.4.541
This study investigates the detection system of oil pollution level using single optical fiber sensor. This study focus on sensing of oil pollution by moisture and iron powder which are representatives of oil pollution factor. In addition, It is placed that the water and iron powder as an oil pollution factor in the oil tank which is the oil circulation in. The oil pollution detection system was measured by the changing of intensity of light and sensing gap. The result of this experimentation not only confirmed the contamination by moisture volume in the oil tank from the section 190ppm to 540ppm, but also monitored the contamination by iron volume from the section 1200ppm to 3500ppm. This study confirmed effectiveness of this detection system using optical fiber sensor. There is expectations of measuring another section by various optical fiber sensor.
Characteristics on Sandwich Panel Welding of a Ni Thin Plate and Porous Ni Thin Plate
Hwang, Chan-Youn ; Yang, Yun-Seok ; Yoo, Young-Tae ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 547~555
DOI : 10.7735/ksmte.2012.21.4.547
This paper focuses on the research of the anode and cathode in the Ni-MH secondary battery. In this paper, the proposed method employs a continuous wave Nd : YAG laser based on the pure Ni instead of the low carbon steel to improve the conductivity although the conventional secondary battery is based on the resistance spot welded with low carbon steel SS41. It welds a sandwich panel using the pure Ni and the porous thin plate, and the tested optimal conditions for the laser power and irradiation speed were 300 and 350 Watt, and 1.0~1.6m/min, respectively. Finally, we observed a ratio, heat input and cross-section and measured the conductivity of the welding section to test the weldability.
Process Optimization for Productivity Improvement during EDM machining of a micro-hole
Kwon, Won-Tae ; Kim, Yeong-Chu ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 556~562
DOI : 10.7735/ksmte.2012.21.4.556
Micro electrical discharge machining (
) has been used for non-conventional material removal. One drawback of
is low productivity. In this study, we tried to find the optimal machining conditions to manufacture the micro hole with an optimal machining time without loss of accuracy. Taguchi method was used to figure out the relation between machining parameters and characteristics of the process. It was found that the electrode wear, the entrance and exit clearance gave a significant effect on the diameter of the micro hole when the diameter of the electrode was identical. Grey relational analysis was used to determine the optimal machining condition for minimum machining time without loss of accuracy. The obtained optimal machining condition was the input voltage of 80V, the capacitance of 680pF, the resistance of
, the feed rate of
/s and the spindle speed of 2900rpm. The machining time was reduced to 48% without loss of accuracy under the optimal machining condition.
Study on Through Paths Inside the Air Pressure Pick-Up Head for Non-Contact Gripper
Kim, Joon-Hyun ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 563~569
DOI : 10.7735/ksmte.2012.21.4.563
In the semiconductor and display device production processes, the handling of sensitive objects needs new carrying technology. Floating carrying motion is a practical alternative solution for non-contact handling of parts and substrates. This paper presents a study of through paths inside the air pressure pick-up head to generate the floating motion. The air motion by conceptual designed paths inside the head gradually develops positive pressure and vacuum between narrow objects. Positive pressure occurs through the head tip before discharging outside of the head. Negative pressure is developed by evacuating the inside head bottom as result of the radial flow connecting the vertical through-holes. The numerical analysis was done to figure out the stable levitation caused by the two acting forces between surfaces. In comparing with the standard case that the levitation gap gets 0.7-0.9 mm, it confirms the suggested head characteristics to show floating capacity in accordance with the head size, number of through-hole, and locations of through-hole in succession of conceptual design for a prototype.
Improved Performance Through Air Conditioner Outdoor Fan Airflow Increase and Relative Cost Reduction
Kim, Jae-Yeol ; Choi, Seung-Hyun ; Kim, Sung-Hyun ; Ki, Suk-Ho ; Yoon, Sung-Un ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 570~574
DOI : 10.7735/ksmte.2012.21.4.570
Spread of household air conditioning system is continued to be increased. Axial fan in the external unit of air conditioning system is for ventilation and air supplying unit, and the related products have been widely adopted as household electronics, automobile engine, big sized blower in factory, tunnel, and subway. In this study, commercial 3-winged propeller fan is modified to shape and modified to 2-winged fan for the airflow increase and cost reduction. Using 3D modelling, the fan shape is modified, and analysis flow is adopted to provide the way to airflow increase and reduce cost while maintaining the same wind capacity.
Effectiveness of the Sensor using Lead Dioxide Electrodes for the Electrochemical Oxygen Demand
Kim, Hong-Won ; Chung, Nam-Yong ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 575~581
DOI : 10.7735/ksmte.2012.21.4.575
The electrochemical oxygen demand (ECOD) is an additional sum parameter, which has not yet found the attention it deserves. It is defined as the oxygen equivalent of the charge consumed during an electrochemical oxidation of the solution. Only one company has yet developed an instrument to determine the ECOD. This instrument uses
-electrodes for the oxidation and has been successfully implemented in an automatic on-line monitor. A general problem of the ECOD determination is the high overpotential of electrochemical oxidations of most organic compounds at conventional electrodes. Here we present a new approach for the ECOD determination, which is based on the use of a solid composite electrodes with highly efficient electro-catalysts for the oxidation of a broad spectrum of different organic compounds. Lead dioxide as an anode material has found commercial application in processes such as the manufacture of sodium per chlorate and chromium regeneration where adsorbed hydroxyl radicals from the electro-oxidation of water are believed to serve as the oxidizing agent. The ECOD sensors based on the Au/
electrode were operated at an optimized applied potential, +1.6 V vs. Ag/AgCl/sat. KCl, in 0.01 M
solution, and reduced the effect of interference (
) and an expended lifetime (more than 6 months). The ECOD sensors were installed in on-line auto-analyzers, and used to analyze real samples.
A Study of Adiabatic Performance for Vacuum Glazing with Design Conditions
Hwang, Il-Sun ; Lee, Young-Lim ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 582~587
DOI : 10.7735/ksmte.2012.21.4.582
Recently, the low-emissivity glass has been used to reduce the energy loss through building windows. However, it simply reduces the inflow of solar rays and has a relatively high heat transmission coefficient. To solve the problems, a high-efficiency vacuum glazing has been under development but it has not been actively used due to its high price and insufficient performance. In this paper, the effects of internal pressure, pillar (spacer) height, pillar diameter, pillar interval, emissivity etc. on the performance of vacuum glazing have been analyzed with three-dimensional computational fluid dynamics and structural analysis. As a result, the performance of vacuum glazing was predicted more accurately and major factors that determine the performance of vacuum glazing were optimized.
Energy Absorption Characteristics of the Al/CFRP/GFRP Hybrid Member under Quasi-static Axial Compressive Load
Kim, Sun-Kyu ; Heo, Uk ; Im, Kwang-Hee ; Jung, Jong-An ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 588~592
DOI : 10.7735/ksmte.2012.21.4.588
This study concentrates the effect of hybridisation on the collapse mode and energy absorption for composite cylinders. The static collapse behavior of laminated(Al/CFRP/GFRP) circular-cylindrical composite shell under quasi-static axial compressive load has been investigated experimentally. Eight different hybrids of laminated(Al/CFRP/GFRP) circular-cylindrical composite shell were fabricated by autoclave. Eight types of composites were tested, namely, Al/carbon fiber/epoxy, Al/glass fiber/epoxy, Al/carbon-carbon-glass/epoxy, Al/carbon-glass-carbon/epoxy, Al/carbon-glass-glass/epoxy, Al/glass-glass-carbon/epoxy, Al/glass-carbon-glass/epoxy and Al/glass-carbon-carbon/epoxy. Collpase modes were highly dominated by the effect of hybridisation. The results also showed that the hybrid member with material sequence of Al-glass-carbon-carbon/epoxy exhibited good energy absorption capability.
Improvement in Mechanical Properties of AZ91D Mg-Alloy through Thixomolding Process
Shin, Dong-Soo ; Chung, Sung-Chong ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 593~600
DOI : 10.7735/ksmte.2012.21.4.593
Thixomolding of Mg-alloy is a semi-solid injection molding process utilizing thixotropic phenomenon. Using this process, higher strength, thinner wall section and tighter tolerance without porosity are obtained. It has been applied for production of near-net-shape magnesium component. To design optimal thixomolding process of Mg-alloy part, molding conditions such as slurry temperature, mold temperature and injection time should be determined properly. Selection of these parameters has been dependent upon engineers` experience and intuitiveness. In this paper, to improve mechanical properties of the thixomolded product, optimal selection of process variables such as injection velocity, barrel temperature and die temperature in the process has been studied through microstructural analysis and Taguchi method. Performance of the process is verified through experiments.
Surface Condition Monitoring in Magnetic Abrasive Polishing of NAK80 Using AE Sensor and Neural Network
Kim, Kwang-Heui ; Shin, Chang-Min ; Kim, Tae-Wan ; Kwak, Jae-Seob ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 601~607
DOI : 10.7735/ksmte.2012.21.4.601
The magnetic abrasive polishing (MAP), for online monitoring with AE sensor attachment, was performed in this study. To predict the surface roughness after the magnetic abrasive polishing of NAK80, the signal data acquired from the AE sensor were analyzed. A dimensionless coefficient, which consisted of average of AErms and standard deviation of AE signal, was defined as a characteristic of the MAP and a prediction model was obtained using least square method. A neural network, which had multiple input parameters from AE signals and polishing conditions, was applied for predicting the surface roughness. As a result of this study, it was seen that there was very close correlation between the AE signal and the surface roughness in the MAP. And then on-line prediction of the surface roughness after the MAP of the NAK80 was possible by the developed prediction model.
Recalculation Research of Material properties for CFRP FEM Non-linear Analysis
Kim, Jung-Ho ; Kim, Chi-Joong ; Cha, Cheon-Seok ; Kim, Ji-Hoon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 608~612
DOI : 10.7735/ksmte.2012.21.4.608
To reduce these costs and time by finite element analysis program has been much research (3~4). At virtual CAE program as like Abaques, Ansys, Ls-dyna and Nastran, the input data of material is got bellow coupon test. In case of carbon composite, it is also put in lamina/laminate properties. There have big problem. If you want to simulate FW(filament winding or wind blade) how do you input material data. Each area of FW is different stacking conditions. It`s too hard that each area is tested for inputting lamina or laminate properties. The composite structure increasing load is applied occurred as the matrix dependence of the crack-induced nonlinearity and nonlinear mobility appears since the initial damage. And uni-direction for this research applies the theory to have been confined to. On this study, we are going to get basically fiber properties and matrix than carbon composite properties for simulating according stacking method by GENOA-MCQ. It is help to simulate easily composite material. Also Calculate the matrix nonlinear for simulating non-linear.
Evaluation of the Weldability of Cu Sheet through the Ultrasonic Metal Welding Experiment
Park, Woo-Yeol ; Jang, Ho-Su ; Kim, Jung-Ho ; Park, Dong-Sam ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 613~618
DOI : 10.7735/ksmte.2012.21.4.613
The Ultrasonic metal welding is used in the solid-phase welding method at room temperature or low temperature state. In welding process, the high frequency vibration energy is delivered to the welding part under the constant pressure for welding. In this study, we aimed to design and manufacture a 40,000 Hz band horn through finite element analysis. By performing modal analysis and harmonic response analysis, the modal analysis result is that the horn frequency was 39,599Hz and the harmonic response result that the horn frequency was 39,533Hz. These results were similar. In order to observe the designed horn`s performance, about 4,000 voltage data was obtained from a light sensor and was analyzed by FFT analysis using Origin Tool. The result RMS amplitude was approximately
at 40,000Hz, and maximum amplitude was
. Using this manufactured horn along with an ultrasonic metal welder and tension tester, the weldability of Cu sheets was evaluated. The maximum tensile force was 66.53 N in the welding condition of 2.0 bar pressure, 60% amplitude, and 0.32 s welding time. In excessive welding conditions, it was revealed that weldability is influenced negatively.
A Study on Tensile Property of MMT (Montmorillonite) Reinforced Chopped Strand Glass Fiber/Vinylester Composites
Jung, Yong-Hwa ; Ku, Ja-Ho ; Lee, Wi-Ro ; Rhee, Kyong-Yop ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 619~624
DOI : 10.7735/ksmte.2012.21.4.619
In this study, MMT/fiber/polymer composites were fabricated by impregnating chopped strand glass mat into a vinylester resin mixed with clay. Tensile tests has been performed by using a universal testing machine to determine the effect of MMT addition on the tensile properties of MMT/chopped strand glass fiber/vinylester composites. And some pictures which are magnified cross section of breaking parts are has been taken by using a FE-SEM to confirm the behavior at breaking. The contents ratio of MMT applied in the composites were 0.5, 1.0, 1.5, and 2.0 wt% respectively. It has been found that the tensile strength and elastic modulus of MMT/chopped strand glass fiber/vinylester composites were improved at a proper content of MMT. Tensile strength and elastic modulus were maximized at a content of 1.0 wt% due to most effective dispersion of MMT. On the contrary, the failure strain was increased as MMT content was increased.
Influence of Process Parameters on the Breathable Film Strength of Polymer Extrusion
Choi, Man-Sung ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 625~632
DOI : 10.7735/ksmte.2012.21.4.625
Optimization of process parameters in polymer extrusion is an important task to reduce manufacturing cost. To determine the optimum values of the process parameters, it is essential to find their influence on the strength of polymer breathable thin film. The significance of six important process parameters namely, extruder cylinder temperature, extruder speed, extruder dies temperature, cooling roll temperature, stretching ratio, stretching roll temperature on breathable film strength of polymer extrusion was determined. Moreover, this paper presents the application of Taguchi method and analysis of variance (ANOVA) for maximization of the breathable film strength influenced by extrusion parameters. The optimum parameter combination of extrusion process was obtained by using the analysis of signal-to-noise ratio. The conclusion revealed that extruder speed and stretching ratio were the most influential factor on the film strength, respectively. The best results of film strength were obtained at higher extruder speed and stretching ratio.
Automated Production System for Manufacturing the Doctor Blades of Laser Printers
Jun, Sung-Hoon ; Lee, Eung-Ki ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 633~638
DOI : 10.7735/ksmte.2012.21.4.633
The doctor blade is a core part of a laser printer and directly influences the printing quality. The main specifications for doctor blades ate for them to be precise and durable. It is necessary to study an automatic production system for doctor blades in order to obtain high-efficient manufacturing processes. In this paper, the technology and the design of the automatic production line has for manufacturing doctor blades has been researched. The automated manufacturing process consists of five steps, which are the supplying of raw material, shearing, bending, bracket supplying, and the laser-spot welding process. The proposed automatic manufacturing system allowed for faster and more reliable production of doctor blades.
Hip Protector against the Impact by Fall Using Air-bag
Park, Ji-Soo ; Kim, Choong-Hyun ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 639~643
DOI : 10.7735/ksmte.2012.21.4.639
The hip protector has been developed using the air-bag which has the capability of attenuating an impact. The impact force using the PVC air-bag was decreased by values of 27.5% on average, compared to the impact force without the air-bag. In the experiment, the standard deviation of the impact force attenuation rate was 0.78%. It means that the dimensions of the air-bag have no significant effects to reduce the impact. We believe that it is possible to design light and cheap hip protectors with air-bag to prevent the femur fracture.
A Study on SS400 Cutting Characteristics using Continuous Wave Fiber Laser
Oh, Yong-Seok ; Lee, Ka-Ram ; Park, Eun-Kyeong ; Yoo, Young-Tae ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 644~650
DOI : 10.7735/ksmte.2012.21.4.644
This paper show the 2kW fiber laser cutting properties of SS400. The study was comparison of traditional 4kW
Laser cutting and 2kW Fiber laser cutting characteristics for the application of Industrial 2D Laser Cutting Machine. The laser used in this investigation was an IPG YLU-2000 multi-mode Ytterbium Fiber machine with a maximum power of 2000W and a wave length of 1070 nm. The laser was used in its Continuous Wave (CW) mode with an approximately top hat beam intensity distribution. Fiber laser high quality cuts at a large range of speeds (ranging from 2000 to 3800 mm/min) which has been obtained for the 2.3mm Sheet of SS400. 2kW power Fiber laser cut was able to max. 20mm sheets of SS400 (speed range from 650 to 850 mm/min). Fiber laser cutting used in conventional hole nozzle could cut 12mm SS400 but used in special dual cutting nozzle could cut 20mm SS400.
Design of PI-PD Controllers to Improve a Response Characteristic in Position Control System
Kim, Jong-Hyeok ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 651~657
DOI : 10.7735/ksmte.2012.21.4.651
In many control fields high position performance is essentially required in reducing the over-shoot phenomena which is produced by improving the quick response in starting and in minimizing the variation of the response characteristic on disturbance and load variation In this paper, the design method for a position control is suggested for constructing the PI-PD controllers by using an internal PD feedback loop in PI and PD control system. Applying this method to the position control system used a DC servo motor as a driver, the transfer PI and PD controllers are designed simultaneously and the coefficients of these controllers are determined by using the transfer function of a plant and a proportional coefficient from mathematical technique. From the result of computer simulation in PI-PD control system by applying this control technique, we can verify the usefulness of this method in rejecting of over-shoot of starting, compensating of response variation on the load variation, and shorting the settling time.
A Study on the Machinability of the Micro-EDM Depending on the Materials
Lee, Sang-Kuk ; Kim, Tae-Hyun ; Hong, Min-Sung ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 658~665
DOI : 10.7735/ksmte.2012.21.4.658
Micro-EDM is widely used in metallic pattern, electronics, nuclear power and industry in the form of precision process. The improvement of Electro Discharge Machining has been on a steady progress since
century. The technology has overcome the limits of the traditional precision process, enabling micro-EDM, micro electrolytic machining, micro drilling, micro punching and laser beam machining, which create versatile products with smaller sizes. What have been known about the major feature of Micro-EDM is high thermal energy so that their products are free from the hardness of their products as long as they are electrical conductor. However, each metal is suspected to have different features and natures even if they are created through the same procedure. In this thesis, the methodology of Micro-EDM and how to categorize them are explained. Also, the nature of the examined materials with surface shape and surface roughnes are analyzed. The results of the experiments are expected to understand surface roughness and workability of other materials for Micro-EDM.
Diagnosis and Evaluation of the Real Time Transformer by the Infrared Thermal Image Equipment
Lee, Chul-Ku ; Baek, Won-Gab ; Kim, Sung-Dai ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 666~671
DOI : 10.7735/ksmte.2012.21.4.666
It was diagnosed customer transformers and other equipment by using non-contact infrared equipment. Examiners can identify not only abnormalities in real time in the field of the transformer immediately, as well as they were able to safely perform the scan. Thanks to successful transformer diagnosis, we can easily diagnose abnormalities of transformer itself which can be caused by deterioration of the oil used as overlaod or refrigerant and we can also diagnose abnomalities from low voltage bushing which can be result by external environmental factors and physical factors and abnomalities from its connections at the same time we found it is very useful at proactive diagnostics.
Tie-bar Elongation Evaluation of Toggle Type Injection Molding Machine
Jung, Hyun-Suk ; Yoo, Joong-Hak ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 672~676
DOI : 10.7735/ksmte.2012.21.4.672
This paper studies the relation between the deformation of platen caused by clamping force, the bending stress and elongation at the tie-bar in injection molding machine of toggle type. These data are analyzed through analytical molding and numerical approach by tensile tester. The effect of bending stress on the stress concentration of teeth and nut system is also analyzed by 2 dimensional numerical approach. The bending stress of tie-bar caused by platen deformation becomes less than 20% of average tensile stress. And the effect of bending stress on stress concentration at teeth and nut system of tie-bar is found to be small.
Finite Element Analysis on Formability of Parabolic Shape
Chung, Sang-Won ; Lee, Kyung-Won ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 677~682
DOI : 10.7735/ksmte.2012.21.4.677
For the product with small diameter, long column, and parabolic shape, the forging formability of the high-carbon steel wire rod was investigated in this study. By using the three-dimensional finite element method, the formability of wire was reviewed by forming analysis for the desired parabolic shape of local part. Analysis results due to forging direction, forging velocity, friction coefficient and constraint location were also investigated. On the basis of these results, it is noted that the forging direction has the big influence when the product with long column is forged. As the forging velocity increases, buckling tends to be limited and formability of parabolic shape is improved. By constraining the lower parabolic shape part to suppress plastic strain, the effect depending on friction coefficient is not almost appeared. And good parabolic shape is obtained at the region of the forging velocity of more than 0.5 m/s.
Semi-Active Control of a Suspension System with a MR Damper of a Large-sized Bus
Yoon, Ho-Sang ; Moon, Il-Dong ; Kim, Jae-Won ; Oh, Chae-Youn ; Lee, Hyung-Won ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 21, issue 4, 2012, Pages 683~690
DOI : 10.7735/ksmte.2012.21.4.683
In this work, the semi-active control of a large-sized bus suspension system with an MR damper was studied. An MR damper model that can aptly describe the hysteretic characteristics of an MR damper was adopted. Parameter values of the MR damper model were suitably modified by considering the maximum damping force of a passive damper used in the suspension system of a real large-sized bus. In addition, a fuzzy logic controller was developed for semi-active control of a suspension system with an MR damper. The vertical acceleration at the attachment point of the MR damper and the relative velocity between sprung and unsprung masses were used as input variables, while voltage was used as the output variable. Straight-ahead driving simulations were performed on a road with a random road profile and on a flat road with a bump. In straight-ahead driving simulations, the vertical acceleration and pitch angle were measured to compare the riding performance of a suspension system with a passive damper with that of a suspension with an MR damper. In addition, a single lane change simulation was performed. In the simulation, the lateral acceleration and roll angle were measured in order to compare the handling performance of a suspension system using a passive damper with that of a suspension system using an MR damper.