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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 29, Issue 12 - Dec 2005
Volume 29, Issue 11 - Nov 2005
Volume 29, Issue 10 - Oct 2005
Volume 29, Issue 9 - Sep 2005
Volume 29, Issue 8 - Aug 2005
Volume 29, Issue 7 - Jul 2005
Volume 29, Issue 6 - Jun 2005
Volume 29, Issue 5 - May 2005
Volume 29, Issue 4 - Apr 2005
Volume 29, Issue 3 - Mar 2005
Volume 29, Issue 2 - Feb 2005
Volume 29, Issue 1 - Jan 2005
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A Development of Wind Tunnel Test System for Synthetic Jet Actuator with Embedded Web Server
Jung Gyu Hong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 639~646
DOI : 10.3795/KSME-A.2005.29.5.639
As the internet communication is prevalent in recent years, it becomes quite possible to monitor and control some mechanical plants from the remote place through the TCP/IP communication. Such a concept is expected to be applied to many industrial systems fur easy maintenance and trouble shooting as well as various kinds of expensive test equipments fo. sharing. Synthetic jet actuate.(SJA) is a kind of high-lifting device to prevent flow separation at high angle of attack and its use for flow control has received a great amount of attention. In this research, remote control and data monitoring system for SJA wind tunnel test is implemented by TCP/IP communication with DSP as a embedded web server. From the tests performed with embedded server, it showed the possibility of reliable remote control system design utilizing the internet communication.
Injection Molded Microcellular Plastic Gear (I) - Process Design for the Microcellular Plastic Gear -
Ha Young Wook ; Chong Tae Hyong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 647~654
DOI : 10.3795/KSME-A.2005.29.5.647
This research Proposes a Process design of injection molded microcellular plastic gears for enhancing the fatigue strength/durability and accuracy of the gears applying thermodynamic instability to microcellular foaming process. To develop the injection molded plastic gears by way of microceliular process, it is absolutely necessary the following two process design. The first is microcellular forming process for enhancing the strength/durability of plastic gears. To be microcellular process succeeded, based on the microcellular principle, mechanical apparatus is designed where nucleation and cell growth are to be generated renewably. The second is the counter pressure process which is mainly fur improving the tooth surface roughness and the accuracy of microcellular gears. For the former process, screw, nozzle and gas equipment are newly designed, and for the latter, counter pressure by nitrogen gas is intentionally brought about into mold cavity when injecting plastic gears. Based on the proposed process design, using gear mold, experiments of injection molding show that, in internal space of plastic gears, microcellular nuclear cells less than 5 lim in diameter have been generated homogeneously via electron microscope photos.
Injection Molded Microcellular Plastic Gear (II) - Characteristics of the Counter Pressurized Microcellular Plastic Gear -
Ha Young Wook ; Takahashi Hideo ; Chong Tae Hyong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 655~662
DOI : 10.3795/KSME-A.2005.29.5.655
This paper investigates the improvement of accuracy and fatigue life of the developed counter pressurized microcellular gears of polyacetal. It is shown that the fatigue life and operational characteristics of the counter pressurized microcellular gears are more improved than conventional injection molded plastic gears by the dynamic gear durability test. For the cases of test sea.5. conventional injection molded sea.5(SGea.) and counter pressurized microcellular gears(CGear) are manufactured. Durability test is performed on both conventional lnjection molded gears and counter pressurized microcellular gears. Accuracy variation and operational characteristics on fatigue life, wear and tooth surface temperature of CGear and Scear are compared and represented. Operational characteristics of the proposed counter pressurized microcellular gears show a good result in this research. The durability limit of counter pressurized microcellular gears is also obtained, and represented by a function of unit load as well as by a function off-factor.
A Cause Analysis of Fatigue Failure of Fuel Pump Block Material(CK35) for Marine Engine
Choi Sung Jong ; Kang Chang Won ; Kim Tae Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 663~670
DOI : 10.3795/KSME-A.2005.29.5.663
DIN CK35 (JIS S35CK) steels have been used as a material in fuel pump blocks for marine engines. Failures in the inner surface of a drilling hole, due to the initiation of fatigue cracks have been frequently reported. However, the mechanism initiating these cracks and growths has not been clearly diagnosed yet. This study was conducted using a scraped fuel pump block, containing an initiated fatigue crack in the inner surface of a drilling hole. Initially, the cracks and fractured surfaces inside the block were investigated using an optical microscope and a SEM (Scanning Electron Microscope). In addition, microstructure observation, fatigue life test and fatigue crack growth test were performed using a specimen, which was taken from the same block. Results from these tests are summarized as follows; (1) The early crack in the block was supposed to occur inside the inner surface of the drilling hole. (2) The fatigue endurance of this material was about 330 Mpa. (3) The early crack was generated in the cavitations created by the breakdown of a big inclusion, or separation between the big inclusion and the base metal, in which the fundamental ingredients of the inclusion were C, 5, and Mn. (4) In order to prevent these types of failures, the suppression of inclusions inflow by improving the casting process, formation of fine inclusions by applying a heat treatment process, and coating of the surface of the drilling hole were required.
Boundary Layer Mesh Generation for Three-Dimensional Geometries with Thin Thickness
Kwon Ki Youn ; Chae Soo-Won ; Lee Byung Chai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 671~679
DOI : 10.3795/KSME-A.2005.29.5.671
A method of generation boundary layer mesh has been presented. This paper describes the generation of semi-unstructured prismatic/tetrahedral meshes for three-dimensional geometries with thin thickness. By of fretting of surface triangle elements prismatic/tetrahedral meshes are generated and using the node relocation method of this research intersected meshes can be efficiently improved. Finally tetrahedral meshes are automatically generated at the rest of the domain. Sample meshes are constructed to demonstrate the mesh generating capability of the proposed algorithm.
Stiffness Analysis of a Low-DOE Parallel Manipulator using the Theory of Reciprocal Screws
Kim Han Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 680~688
DOI : 10.3795/KSME-A.2005.29.5.680
This paper presents a methodology for the stiffness analysis of a low-DOF parallel manipulator. A low-DOF parallel manipulator is a spatial parallel manipulator which has less than six degrees of freedom. The reciprocal screws of actuations and constraints in each leg can be determined by making use of the theory of reciprocal screws, which provide information about reaction forces due to actuations and constraints. When pure farce is applied to a leg, the leg stiffness is modeled as a linear spring along the line. For pure couple, it is modeled as a rotational spring about the axis. It is shown that the stiffness model of an it_DOF parallel nipulator consists of F springs related to actuations and 6-F springs related to constraints connected from the moving platform to the base in parallel. The 6x f Cartesian stiffness matrix is derived, which is the sum of the Cartesian stiffness matrices of actuations and constraints. Finally, the 3-UPU, 3-PRRR, and Tricept parallel manipulators are used as examples to demonstrate the methodology.
Reliability Estimation of Door Hinge for Rome Appliances
Kim Jin Woo ; Shin Jae Chul ; Kim Myung Soo ; Moon Ji Seob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 689~697
DOI : 10.3795/KSME-A.2005.29.5.689
This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor,
life and its lower bound with
confidence at worst case use condition are estimated by analyzing the accelerated life test data.
NURBS Curve Interpolator for Controlling the Surface Roughness
Choi In hugh ; Jung Tae sung ; Yang Min Yang ; Lee Dong yoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 698~706
DOI : 10.3795/KSME-A.2005.29.5.698
Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This NURBS interpolation adopts a feedrate optimizing strategy based on both the geometrical information and dynamic properties. In case of a finish cut using a ball-end mill, the curve interpolator needs to take the machining process into account for more improved surface, while reducing the polishing time. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A particular curve interpolation algorithm is proposed fur generating feedrate commands which are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented.
Optimization of Passive Mixer for Enhanced Mixing in a Micro-channel by Using Lattice Bloltzmann Method
Han Gyu suk ; Byun Sung Joon ; Yoon Joon Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 707~715
DOI : 10.3795/KSME-A.2005.29.5.707
In this work, Scalar Passive code in Lattice Boltzmann Method is employed to simulate two-phase flow of low Reynolds number in a micro-channel. The mixing characteristics in a micro-channel is a function of Peclet number. The mixing length increases with the Peclet number. It is found that with the inclusion of static elements at the channel, rapid mixing of two liquids can be achieved, as shown by the results of computer simulations. The enhancement in mixing performance is thought to be caused by the generation of eddies and by lateral velocity component when the mixture flows past static elements. The results indicate that the size of static element has more effect on the mixing than the number of static element.
Hybrid Component Mode Synthesis Considering Residual Dynamic Flexibility Attachment Mode
Cha Hyun Joo ; Kim Jin Ho ; Lee Shi Bok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 716~725
DOI : 10.3795/KSME-A.2005.29.5.716
The method of substructure synthesis o. component mode synthesis(CMS) provides an effective means of dynamic analysis of very large and/or complex structures. In this study, residual dynamic flexibility attachment modes in hybrid component mode synthesis are considered for the purpose of exactly compensating the effect of higher order truncated modes. Following this way, the analysis accuracy of the synthesized structure can be improved effectively with less computational effort. In order to show the accuracy and effectiveness of the proposed hybrid component mode synthesis(HCMS), numerical experiments were carried out for the models of a clamped-clamped beam. The results verified the effectiveness of the proposed method.
Machining Accuracy for Large Optical Mirror using On-Machine Spherical Surface ]Referenced Shack-Hartmann System
Hong Jong Hui ; Oh Chang Jin ; Lee Eung Suk ; Kim Ock Hyn ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 726~733
DOI : 10.3795/KSME-A.2005.29.5.726
A spherical surface referenced Shack-Hartmann method is studied for inspecting machining accuracy of large concave mirror This method is so strong to the vibration environment for using as an on-machine inspection system during polishing process of large optics comparing with the interferometry. The measuring uncertainty of the system is shown as less than p-v 150 m. On-machine measured surface profile data with this method is used for feed back control of the polishing time or depth to improve the surface profile accuracy of large concave mirror. Also, the spherical surface referenced Shack-Hartmann method is useful for measuring aspheric such as parabolic or hyperbolic surface profile, comparing that the interferomehy needs a special null lens, which is to be a reference and difficult to fabricate.
Integrity Evaluation Model for a Straight Pipe with Local Wall Thinning Defect
Park Chi Yong ; Kim Jin Weon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 734~742
DOI : 10.3795/KSME-A.2005.29.5.734
The present study proposes the integrity evaluation model for a straight pipe with local wall thinning defect, which reflects the characteristics of training shape and loading condition in the Piping of nuclear power plant. For this purpose, a series of finite element analyses are performed under various defect geometries and loading conditions, and real pipe experiment data performed previously is employed. The model includes the effect of thinning length as well as thinning depth and width, and also it considers the combined loading effect between internal pressure and bending moment. The proposed model has been validated using the results of finite element analysis and pipe experiment data. The results indicate that the proposed model provides more reliable predictions of pipe failure than the current existing model, in terms of accuracy, consistency, and conservativeness of results.
Modeling on an Antenna Flexible Characteristics of a Prototype Gimbal with an Antenna and Major Design Factors to determine a System Bandwidth
Baek Joo Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 743~753
DOI : 10.3795/KSME-A.2005.29.5.743
The model of azimuth driving servo system with a flexible antenna in a prototype gimbal has been derived in this work. The validity of the model is verified by comparing the result of the model with that of experiment. It is found that one should consider an antenna as a flexible body in case of modeling the dynamics of the gimbal with an antenna. It is also known that the effect of reducing backlash magnitude for extending the bandwidth in the system with a flexible antenna is smaller than the system with a stiff antenna. It is thought that the model-based design optimization of the gimbal with an antenna will be possible by virtue of the derived model, when a weight reduction and a bandwidth extension are required.
Development of Optimum Global Failure Prediction Model for Steam Generator Tube with Two Parallel Cracks
Moon Seong ln ; Chang Yoon Suk ; Lee Jin Ho ; Song Myung Ho ; Choi Young Hwan ; Kim Joung Soo ; Kim Young Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 754~761
DOI : 10.3795/KSME-A.2005.29.5.754
The 40\% of wall thickness criterion which has been used as a plugging rule of steam generator tubes is applicable only to a single cracked tube. In the previous studies performed by authors, several global failure prediction models were introduced to estimate the failure loads of steam generator tubes containing two adjacent parallel axial through-wall cracks. These models were applied for thin plates with two parallel cracks and the COD base model was selected as the optimum one. The objective of this study is to verify the applicability of the proposed optimum global failure prediction model for real steam generator tubes with two parallel axial through-wall cracks. For the sake of this, a series of plastic collapse tests and finite element analyses have been carried out fur the steam generator tubes with two machined parallel axial through-wall cracks. Thereby, it was proven that the proposed optimum failure prediction model can be used as the best one to estimate the failure load quite well. Also, interaction effects between two adjacent cracks were assessed through additional finite element analyses to investigate the effect on the global failure behavior.
Analysis of a Bydrodynamic Bearing of a BDD Spindle Motor Due to Elevated Temperature
Kim Kwan Soo ; Kim Hak Woon ; Lee Haeng Soo ; Kim Chul Soon ; Jang Gun Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 762~769
DOI : 10.3795/KSME-A.2005.29.5.762
This paper presents a method to investigate the characteristics of a hydrodynamic bearing of a HDD spindle motor due to elevated temperature considering the variation of the clearance as well as the lubricant viscosity. Iterative finite element analysis of the heat conduction and the thermal deformation is performed to determine the viscosity and clearance of a hydrodynamic bearing due to elevated temperature until the temperature of the bearing area converges. Proposed method is verified by comparing the calculated temperature with the measured one in elevated surrounding temperature as well as in room temperature. This research shows that elevated temperature changes the clearance as well as the lubricant viscosity of the hydrodynamic bearing of a HDD spindle motor. Once the viscosity and the clearance of a hydrodynamic bearing of a HDD spindle motor are determined, finite element analysis of the Reynolds equation is performed to investigate the static and dynamic characteristics of a hydrodynamic bearing of a HDB spindle motor due to elevated temperature. It also shows that the variation of clearance due to elevated temperature is another important design consideration to affect the static and dynamic characteristics of a hydrodynamic bearing of a HDD spindle motor
A Measuring Method for Positioning Characteristics Analysis of NC Machine Controller using Dynamometer
Kim Hyung Gon ; An Dong Youl ; Lee Eung Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 770~776
DOI : 10.3795/KSME-A.2005.29.5.770
The gains fur NC controller parameter are fixed when the controller is combined with a machine. However, the characteristics of controller could be changed as it has being used by the machine or other environmental conditions. Those result in that the tool positioning accuracy is influenced. The loading torque in servo motor influences on the tool positioning accuracy and it is controlled by the parameter gains. It is required to analyze the torque variation with angular positioning accuracy of the servo motor. This study focus on a measuring method and device for verifying angular positioning accuracy of NC servo motor. We used a high resolution An converter for acquiring analogue signal of rotary encoder in servo motor. The positional accuracy for a nominal tool path, which is generated by the combination of axial movements (X,Y,Z), is analyzed with the servo motor torque. The current variation signal is acquired at the power line using a hall sensor and converted to the loading torque of servo motor. The method of measurement and analysis proposed in this study will be used for determining the gains of parameter in NC controller. This gain tuning is also necessary when the controller is set up at a machine.
Swing-Motion Control System Design for the Crane Based on Simultaneous Optimum Design Approach
Jang Ji Seong ; Kim Young Bok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 5, 2005, Pages 777~785
DOI : 10.3795/KSME-A.2005.29.5.777
The swing motion control problem of a container hanging on the trolly is considered in the paper. In the container crane control problem, suppressing the residual swing motion of the container at the end of acceleration, deceleration or the case of that the unexpected disturbance input exists is main issue. For this problem, in general, many trolley motion control strategies are introduced and applied. In this paper, we introduce and synthesize a swing motion control system in which a small auxiliary mass is installed on the spreader made by ourselves. In this control system, the actuator reacting against the auxiliary mass applies inertial control forces to the container to reduce the swing motion in the desired manner. In many studies, the controllers used to suppress the vibration have been synthesized for the given mathematical model of plants. And, the designers have not been able to utilize the degree of freedom to adjust the structural parameters for the control object. To overcome this problem, so called `Structure/control Simultaneous Method` is used. In this paper, the simultaneous design method is used to determine the optimum weight of moving mass such that the optimal system performance would be achieved. And the experimental result shows that the proposed control strategy is useful to the case of that the controlled system is exposed to the uncertainties and, robust to the unexpected disturbance inputs.