Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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 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
CWT-Based Method for Identifying the Location of the Impact Source in Buried Pipes
Kim, Eui-Youl ; Kim, Min-Su ; Lee, Sang-Kwon ; Koh, Jae-Pil ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1555~1565
DOI : 10.3795/KSME-A.2010.34.11.1555
This paper presents a new method for indentifying the location of impact source in a buried duct. In a gas pipeline, the problem of leakage occurs due to the mechanical load exerted by construction equipment. Such leakage can cause catastrophic disasters in gas supply industries. Generally, the cross-correlation method has been used for indentifying the location of impact source in a pipeline. Since this method involves the use of the dispersive acoustic wave, it derives an amount of error in process of estimating the time delay between acoustic sensors. The object of this paper is to estimate the time delay in the arrival of the direct wave by using the wavelet transform instead of the dispersive wave. The wavelet transform based method gives more accurate estimates of the impact location than the cross-correlation method does. This method is successfully used to identify the location of impact force in an actual buried gas duct.
Key Parameter of Peel-off Test for Reliability Assessment of Toner Film
Kim, Kwang-Il ; Kim, Dae-Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1567~1573
DOI : 10.3795/KSME-A.2010.34.11.1567
In printing systems, the reliability of printed material depends on the ability of the toner film to remain adhered to the paper surface. In order to measure the strength between the toner film and the paper surface, a peel-off test is often performed. After conducting the test, the amount of toner film remaining on the paper is measured in order to determine the interfacial strength. The results of this test can be affected by many factors such as the peeling rate, weight of the roller used, and dwell time of tape. Sensitivity analysis was performed with respect to peeling rate, weight of roller and dwell time of tape at different levels. It was found that the interfacial strength increased with an increase in these main parameters. On the other hand, the trend with respect to the percentage of toner loss was different. Further, the interfacial strength and percentage of toner loss were significantly affected by the peeling rate.
Analysis of Motion of Batoid Fins for Thrust Generation by Using Fluid-Structure Interaction Method
Kwon, Dong-Hyun ; Lee, Jong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1575~1580
DOI : 10.3795/KSME-A.2010.34.11.1575
Recently, the development of bio-mimetic underwater vehicles that can emulate the characteristic movements of marine fish and mammals has attracted considerable attention. In this study, the motion of the batoid (i.e., cownose ray) fin that facilitates excellent cruising and maneuvering during underwater movement has been studied. The velocity achieved and distance covered with each fin movement are numerically studied. A fluid-structure interaction method is used to perform 3D time-dependent numerical analysis, wherein an adaptive mesh is employed to account for the large deformation of a fin interacting with a fluid. The results of a preliminary study show that the thrust of a ray fin is highly dependent on the frequency. Further, once the fin amplitude required for generating a given thrust is evaluated for the conditions experienced by an actual ray, the frequency and amplitude values for achieving better thrust are determined.
Human-Oriented Design of Backrest of Office Chair Using Haptic-aided Design and Lumber Angle Prediction
Lee, Sang-Duck ; Lee, Hae-A ; Song, Jae-Bok ; Chae, Soo-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1581~1586
DOI : 10.3795/KSME-A.2010.34.11.1581
Haptic-aided design (HAD) involves the use of a haptic simulator in place of physical prototypes in the design and development of products with which human beings interact physically. The development time and cost can be significantly reduced by adopting this HAD scheme. Although both physical and emotional factors are equally important, only the emotional factors were taken into consideration in the previous HAD process. Consequently, the design of the products was sometimes unsatisfactory from the viewpoint of ergonomics, even though users were emotionally satisfied with the products. To overcome this problem, in this study, we propose a new human-oriented design methodology that is enhanced by taking the physical factors into consideration. The HAD scheme was verified by using a haptic chair simulator to design a tilt mechanism of an office chair for which the stiffness of the backrest can be adjusted; then, the design was simulated using MADYMO. The results show that the proposed method can reflect both the physical and emotional factors to modify the design in real-time.
Effects of Specimen Geometry on Stress Distribution in Sandwich Specimen Under Combined Loads
Park, Su-Kyeong ; Hong, Sung-Tae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1587~1592
DOI : 10.3795/KSME-A.2010.34.11.1587
The effects of specimen geometry and loading conditions on the stress distribution in a sandwich specimen under combined loads are investigated by elastic finite element analysis. A commercial software NASTRAN is used in plain-strain two-dimensional finite element analysis of sandwich specimens; the analysis was performed for three different specimen shape factors and four different combined displacement conditions. The results of computational analysis suggest that the effect of the combined displacement angle, which is defined as the ratio of the shear displacement to the normal displacement, on the size of the non-homogeneous stress distribution is observed only in the case of the shear stress and von Mises stress. Also as the combined displacement angle increases, the size of the nonhomogeneous stress distribution decreases in the case of the shear stress and increases in the case of the von Mises stress. In addition, as the specimen shape factor, which is defined as the ratio of the specimen length to the height, increases, the size of the non-homogeneous stress distribution under combined displacement conditions decreases significantly.
Numerical Analysis and Optimum Design of Disposable Drug Infuser Using Fluid-Structure Interaction Technique
Kim, Heon-Young ; Kim, Hak-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1595~1602
DOI : 10.3795/KSME-A.2010.34.11.1595
A disposable drug infuser is used to provide drugs to patients who are not hospitalized; in this infuser, an elastic recovery force is exerted by a diaphragm made of a rubber-like materialsuch that a constant amount of drugs is provided to a patient. The drug infuser has to control the speed and amount of drugs to be released, as well as the overall duration for which they are to be administered. However, in a drug infuser with an elastic diaphragm, the infusion pressure depends on the amount of drug remaining within the infuser, and the amount of drug infused gradually decreases as the amount remaining in the infuser decreases. In this study, a finite element procedure involving the application of the fluid-structure interaction technique was developed and the performance of the elastic type disposable drug infuser was analyzed. The optimum design for ensuring that the infusion pressure remains constant throughout the duration of usage, including during infusion and discharge, was determined by this procedure.
Comparative Study of Approximate Optimization Techniques in CAE-Based Structural Design
Song, Chang-Yong ; Lee, Jong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1603~1611
DOI : 10.3795/KSME-A.2010.34.11.1603
The comparative study of regression-model-based approximate optimization techniques used in the strength design of an automotive knuckle component that will be under bump and brake loading conditions is carried out. The design problem is formulated such that the cross-sectional sizing variables are determined by minimizing the weight of the knuckle component that is subjected to stresses, deformations, and vibration frequency constraints. The techniques used in the comparative study are sequential approximate optimization (SAO), sequential two-point diagonal quadratic approximate optimization (STDQAO), and approximate optimization based on enhanced moving least squares method (MLSM), such as CF (constraint feasible)-MLSM and Post-MLSM. Commercial process integration and design optimization (PIDO) tools are utilized for the application of SAO and STDQAO. The enhanced MLSM-based approximate optimization techniques are newly developed to ensure constraint feasibility. The results of the approximate optimization techniques are compared with those of actual non-approximate optimization to evaluate their numerical performances.
Nano-Positioning of High-Power Ultrasonic Linear Motor Stage in High-Vacuum Environment
Kim, Wan-Soo ; Lee, Dong-Jin ; Lee, Sun-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1613~1622
DOI : 10.3795/KSME-A.2010.34.11.1613
In this paper, the ultraprecision positioning control of an ultrasonic linear motor in a high-vacuum environment is presented. The bolt-clamped Langivin type transducer (BLT) with the 3rd longitudinal; and 6th lateral vibration modes was developed, which was excited by using the Eigen resonance frequency for two vibration modes in order to generate stable and high power. In practical applications, however, even if a geometrical design has an Eigen frequency, discordance between both mode frequencies can be generated by the contact mechanism and because of manufacturing errors as well as environmental factors. Both mode frequencies were precisely matched by adjusting the impedence. By using this method, the BLT can be driven under any environmental conditions. The nominal characteristic trajectory following(NCTF) control method was adopted to control the positioning of the system in vacuum. The developed linear motor stage show high positioning accuracy with 5 nm.
Reduction of the Roll-Over of the Sector Tooth for Achieving Improved Recliner Locking Performance
Lee, Sang-Hoon ; Choi, Hong-Seok ; Chang, Myung-Jin ; Kim, Dong-Su ; Bae, Jae-Ho ; Ko, Dae-Cheol ; Kim, Byung-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1623~1630
DOI : 10.3795/KSME-A.2010.34.11.1623
In this study, effective forming methods for reducing the roll-over of a sector tooth, which is a main component of an automotive seat recliner, are proposed. Due to the large amount of roll-over, accurate contact between the inner gear of a sector tooth and the outer gear of a pawl tooth cannot be normally achieved; thus sensitivity and safety for the passengers decrease. To overcome the aforementioned drawback, we investigated the effect of flowcontrol forming methods involving local embossing die, coining punch, and VIC (Variable Inverse Clearance) on the roll-over depth by FE-analysis and an experiment. The results of a fine-blanking experiment for verifying the proposed methods showed that VIC type is decidedly superior from the aspects of reduction of roll-over and tool strength of the sector tooth.
Localized Oxidation of (100) Silicon Surface by Pulsed Electrochemical Processes Based on AFM
Lee, Jeong-Min ; Kim, Sun-Ho ; Park, Jeong-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1631~1636
DOI : 10.3795/KSME-A.2010.34.11.1631
In this study, we demonstrate a nano-scale lithograph obtained on localized (100) silicon (p-type) surface using by modified AFM (Atomic force microscope) apparatuses and by adopting controlling methods. AFM-based experimental apparatuses are connected to a customized pulse generator that supplies electricity between the conductive tip and the silicon surface, while maintaining a constant humidity throughout the lithography process. The pulse durations are controlled according to various experimental conditions. The electrochemical reaction induced by the pulses occurs in the gap between the conductive tip and silicon surface and result in the formation of nanoscale oxide particles. Oxide particles with various heights and widths can be created by AFM surface modification; the size of the oxide particle depends on the pulse durations and the applied electrical conditions under a humid environment.
Fabrication of High-Quality Diffractive-Lens Mold having Submicron Patterns
Woo, Do-Kyun ; Hane, Kazuhiro ; Lee, Sun-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1637~1642
DOI : 10.3795/KSME-A.2010.34.11.1637
In this paper, we present the fabrication of a high-quality diffractive-lens mold having submicron patterns, which is suitable for an ultra-slim optical system. In order to fabricate high-quality diffractive lens with a variety of submicron patterns, the multi-alignment method was used; high-resolution electron-beam lithography and FAB plasma etching were carried out to obtain the patterns. The most important key technology in the multi-alignment method is to reduce alignment error, lithography error, and etching error. In this paper, these major fabrication errors were minimized, and a high-quality diffractive lens with a diameter of
(NA = 0.25), minimum pattern width of 226 nm, and thickness of 819 nm was successfully fabricated.
Control of Polarity by Magnetic Array Table in Magnetic Abrasive Polishing Process
Gang, Han-Sung ; Kim, Tae-Hui ; Kawk, Jae-Seob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1643~1648
DOI : 10.3795/KSME-A.2010.34.11.1643
It is very difficult to polish non-magnetic materials by the magnetic abrasive polishing (MAP) process because magnetic force is required for MAP, but the magnetic force for non.magnetic materials is low. In this study, we aimed to develop a magnetic array table and control the magnetic polarity such that the magnetic force can be increased for the MAP of non-magnetic materials. The newly designed magnetic array table has 32 electro magnets, and the magnetic polarity of each electro-magnet can be easily controlled by changing the electric polarity. It was analytically verified that the magnetic flux density of non-magnetic materials can be varied by varying the applied magnetic polarity.
Effects of Molding Condition on Surface Unevenness of GFRP Composites in Compression Molding
Kim, Hyoung-Seok ; Kim, Jin-Woo ; Kim, Yong-Jae ; Lee, Dong-Gi ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1649~1657
DOI : 10.3795/KSME-A.2010.34.11.1649
We have investigated the unexpected phenomena on the surface of molded GFRP composites. The major cause of the unevenness, as a result of which the surface becomes rough, is a shrinking of the matrix in the process of holding pressure and cooling temperature. The higher holding pressure load in a molding process and the lower demolding temperature in an annealing experiment, the better GFRP composites moldings improved its appearance. In addition, by taking the holding pressure and demolding temperature into consideration, we evaluate the process that causes the surface unevenness and the variation in the fiber projection height.
Compressive Characteristics of New Wire-woven Cellular Metal
Ko, Gyeong-Deuk ; Lee, Ki-Won ; Kang, Ki-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1659~1666
DOI : 10.3795/KSME-A.2010.34.11.1659
In this study, a new type of wire-woven cellular metal named WBD(wire-woven bulk diamond) was developed. Like WBK(wire-woven bulk Kagome), WBD is composed of helically formed wires; WBK was introduced a few years ago, and its mechanical, thermal properties, and engineering applications have been extensively investigated. The number of wires that pass by one another at each cross point in WBD is four, whereas that in WBK is three. The mechanical behavior of WBD subjected to compression was investigated and the results were compared to those for WBK. For a given slenderness ratio the density and yield strength of WBD were about twice as high as those for WBK, but elastic stiffness of WBD was not that higher than that for WBK.
Study on Fatigue Life Estimation for Aircraft Engine Support Structure
Hur, Jang-Wook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1667~1674
DOI : 10.3795/KSME-A.2010.34.11.1667
The fatigue life is estimated while determining the reliability of aircraft structures. In this study, the estimation of fatigue life was carried out on the basis of a cumulative damage theory; the working S-N curve and the equivalent stress on the engine support structure significantly affect the safety of the aircraft. The maximum stress observed was 1,080 MPa in the case of scissors link under crash load condition, and there was a 5% margin for the allowable stress corresponding to the temperature reduction factor. The maximum stress was 876 MPa, and the stress equation coefficient had a maximum value of 0.019 MPa/N in the case of scissors link under fatigue loads. In the results of the fatigue life analysis, the safety life in a fretting area of scissors link upper part was 416,667 flight hour, and other parts showed to infinite life. Therefore, it was demonstrated that the fatigue life requirement of aircraft engine support structure (scissors link, straight link) could be satisfied.
Limit Loads for Circular Wall-Thinned Feeder Pipes Subjected to Bending and Internal Pressure.
Je, Jin-Ho ; Lee, Kuk-Hee ; Chung, Ha-Joo ; Kim, Jong-Sung ; Kim, Yun-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1675~1680
DOI : 10.3795/KSME-A.2010.34.11.1675
Flow Accelerated Corrosion (FAC) occurring during in-service conditions results in localized wall-thinning in the feeder pipes of CANDU. The wall-thinning of the feeder pipes is the main degradation mechanisms affecting the integrity of piping systems. In this paper, we assess the integrity of wall-thinned feeder pipes by limit load analysis. The limit loads for wall-thinning feeder pipes subjected to in-plane bending and internal pressure were determined on the basis of finte element limit analyses. The limit loads are determined from the results of limit analyses of elasticperfectly-plastic materials using the large geometry change. Closed-form approximations of limit load solutions for wall-thinning feeder pipes subjected to in-plane bending and pressure are proposed.
Fault Classification for Rotating Machinery Using Support Vector Machines with Optimal Features Corresponding to Each Fault Type
Kim, Yang-Seok ; Lee, Do-Hwan ; Kim, Seong-Kook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1681~1689
DOI : 10.3795/KSME-A.2010.34.11.1681
Several studies on the use of Support Vector Machines (SVMs) for diagnosing rotating machinery have been successfully carried out, but the fault classification depends on the input features as well as a multi-classification scheme, binary optimizer, kernel function, and the parameter to be used in the kernel function. Most of the published papers on multiclass SVM applications report the use of the same features to classify the faults. In this study, simple statistical features are determined on the basis of time domain vibration signals for various fault conditions, and the optimal features for each fault condition are selected. Then, the optimal features are used in the SVM training and in the classification of each fault condition. Simulation results using experimental data show that the results of the proposed stepwise classification approach with a relatively short training time are comparable to those for a single multi-class SVM.
Expansion of Sensitivity Analysis for Statistical Moments and Probability Constraints to Non-Normal Variables
Huh, Jae-Sung ; Kwak, Byung-Man ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1691~1696
DOI : 10.3795/KSME-A.2010.34.11.1691
The efforts of reflecting the system's uncertainties in design step have been made and robust optimization or reliabilitybased design optimization are examples of the most famous methodologies. The statistical moments of a performance function and the constraints corresponding to probability conditions are involved in the formulation of these methodologies. Therefore, it is essential to effectively and accurately calculate them. The sensitivities of these methodologies have to be determined when nonlinear programming is utilized during the optimization process. The sensitivity of statistical moments and probability constraints is expressed in the integral form and limited to the normal random variable; we aim to expand the sensitivity formulation to nonnormal variables. Additional functional calculation will not be required when statistical moments and failure or satisfaction probabilities are already obtained at a design point. On the other hand, the accuracy of the sensitivity results could be worse than that of the moments because the target function is expressed as a product of the performance function and the explicit functions derived from probability density functions.
A Study of Life Characteristic of Hydraulic Hose Assembly by Adopting Complex Accelerated Model with Acceleration Factors of Pressure and Temperature
Lee, Gi-Chun ; Kim, Hyoung-Eui ; Cho, You-Hee ; Kim, Jae-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1697~1703
DOI : 10.3795/KSME-A.2010.34.11.1697
Hydraulic hoses are used as pipelines for transferring power from hydraulic systems in various machineries such as construction equipments, automobiles, and aircraft. Hydraulic hoses protect the system from vibration or impacts, and they are being used to transfer energy in all segments of the industry. In order to protect the system from various external environmental conditions, hydraulic hose assemblies must be able to withstand a wide range of temperatures and pressures, as well as variations in other factors. In previous studies, an acceleration model for the hydraulic hose assembly was developed by taking into account only one of the acceleration factors (temperature or pressure). Therefore, the objective of this study is to develop a comprehensive acceleration model that takes both temperature and pressure into consideration.
Evaluation of Statistical Fatigue Life of Hybrid Composite Joints in Low-Floor Bus
Jung, Dal-Woo ; Choi, Nak-Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1705~1713
DOI : 10.3795/KSME-A.2010.34.11.1705
The reliable fatigue life for hybrid composite joint structures was estimated by a statistical method for evaluating fatigue life; the results of the fatigue test varied widely. Cyclic bending tests were performed on a cantilever beam with a hybrid composite joint, which was developed for the body of a low-floor bus. In order to estimate the fatigue life of the hybrid composite joint structure by comparing the data obtained during the fatigue tests, the most suitable probabilistic density function among the normal, lognormal, and Weibull distributions was selected. The probabilistic-stress-life (P-S-N) curves calculated by using the selected Weibull distribution was suggested for process of statistical fatigue life estimation and reliability design.
Characterization of Crack Healing of Si
Ceramic Structures According to Crack Length and Coating Methods
Nam, Ki-Woo ; Moon, Chang-Kwon ; Park, Sang-Hyun ; Eun, Kyung-Ki ; Kim, Jong-Soon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1715~1720
DOI : 10.3795/KSME-A.2010.34.11.1715
In this study, we analyzed the crack-healing characteristics of specimens; different crack lengths and coating methods of
ceramic structures with long cracks were analyzed. Cracks with lengths of about
were obtained using a Vickers indenter for a load of 24.5-98 N. In the case of a crack obtained by applying a load of 24.5 N, the crack-healed specimen with
nanocolloid coating exhibited the highest bending strength, which was higher than that of a smooth specimen by 140%, but the bending strength of a crack-healed specimen that had a
nanocolloid coating and originally had multiple cracks was lower than that of a smooth specimen. However, when compared to the cracked specimens, the bending strength of most specimens with multiple cracks increased slightly. On the basis of these results, the crack-healing characteristics of
ceramic structures with multiple indentations were studied for different coating methods. The most effective coating method for long-crack specimens was hydrostatic pressure coating.
Fabrication of Carbon Microneedle Arrays with High Aspect Ratios and The Control of Hydrophobicity of These Arrays for Bio-Applications
Lee, Jung-A ; Lee, Seok-Woo ; Lee, Seung-Seob ; Park, Se-Il ; Lee, Kwang-Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1721~1725
DOI : 10.3795/KSME-A.2010.34.11.1721
This paper reports the fabrication of geometry-controlled carbon microneedles by a backside exposure method and pyrolysis. The SU-8 microneedles are a polymer precursor in a carbonization process, which geometries such as base diameter, spacing, and aspect ratio can be controlled in a photolithography step. Using this fabrication method, highly reproducible carbon microneedles, which have high aspect ratios of more than 10 and very sharp nanotips, can be realized. The quartz surface with carbon microneedles becomes very hydrophilic and its wettability is adjusted by carrying out the silane treatment. In the carbon microneedle array (
), the contact angle is extremly enhanced (
); this will be advantageous in developing low-drag microfluidics and labs-on-a-chip as well as in other bio-applications.
Forensic Engineering Study on Assessment of Damage to Aerial Lifter Parts
Kim, Eui-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1727~1732
DOI : 10.3795/KSME-A.2010.34.11.1727
Forensic engineering is the area of expertise of people qualified to serve as engineering experts in courts of law or during arbitration proceedings. An aerial-lifter can lift and carry load, including people, using power. Recently, failure of aerial-lifter internal parts while working and sweeping 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 accidents, such as a vehicle catching fire is the failure of oil pressure machine and the supporting pin. The results of formal inspections and engineering tests can reveal the cause for the failure of the mechanical parts. Therefore, the failure mechanism is analyzed by adopting fractography methods and by applying an instrumented indentation technique to compare the material properties of the reference part with those of the malfunctioning part.
Drop Analysis of a Package and Cushion Performance of Drum Washing Machine
Kim, Chang-Sub ; Bae, Bong-Kook ; Sung, Do-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1733~1740
DOI : 10.3795/KSME-A.2010.34.11.1733
The analysis of the dynamic behavior of the packaging of a drum washing machine has been carried out under the drop impact conditions. LS-DYNA software is used for performing the finite element analysis, and the validations are performed by comparing with the impact acceleration, effective stress and deformation of cushioned package with high-speed camera during free drop test. By analyzing the cushion characteristics and the design parameters of the original packaging, a packaging with an improved design is developed, and this design is validated on the basis of the results of the distribution test which consists of drop test, vibration test, stacking test, squeez test and so on. The drop impact simulation and analysis methods developed in this study can be adopted to successfully improve the cushioning provided by the packaging and to reduce the cost involved in developing new packaging for drum washing machines.
Design of an Economic Service Robot Hand Based on Biomimetics and TRIZ
Ko, Hun-Keon ; Cho, Chang-Hee ; Kim, Kwon-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1741~1747
DOI : 10.3795/KSME-A.2010.34.11.1741
This work presents a study on the design of an economic service robot hand for tele-presence manipulators. The conceptual design of new robot hand is derived from biomimetics approach. Guided by the analysis of human arm' musculoskeletal structure, the fingers are actuated by cables and actuators in the forearm. High tension in the cables is achieved by screw-nut mechanism driven by DC motors. A set of combination springs is incorporated in each of the screw-nut mechanism for easy control of gripping force. The first prototype revealed difficulties with finger control and coupling problem between gripping force and wrist movement. The solutions to these problems have been derived from the contradiction analysis of TRIZ. The second design has been verified by tests on various objects with different weight and shape for full range of wrist motion.
Prediction of Lift Performance of Automotive Glass Using Finite Element Analysis
Moon, Hyung-Il ; Kim, Heon-Young ; Choi, Cheon ; Lee, In-Heok ; Kim, Do-Hyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1749~1755
DOI : 10.3795/KSME-A.2010.34.11.1749
The performance of power window system was decided by driving characteristics of the window regulator part and reaction by the glass run. The performance of power window system usually has been predicted by experimental methods. In this paper, an analytical method using the explicit code was suggested to overcome the limit of the experimental methods. The friction coefficient of glass run was obtained by the friction test at various conditions and the Mooney-Rivlin model was used. Also, a mechanism of window regulator consisted of the fast belt system and the slip ring elements. And, we conducted the analysis considering characteristic of a motor and obtained the lifting speed of automotive glass with high reliability
Development of Rotordynamics Program Based on the 2D Finite Element Method for Flywheel Energy Storage System
Gu, Dong-Sik ; Bae, Yong-Cae ; Lee, Wook-Ryun ; Kim, Jae-Gu ; Kim, Hyo-Jung ; Choi, Byeong-Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1757~1763
DOI : 10.3795/KSME-A.2010.34.11.1757
Flywheel energy storage system (FESS) is defined as a high speed rotating flywheel system that can save surplus electric power. The FESS is proposed as an efficient energy storage system because it can accumulate a large amount of energy when it is operated at a high rotating speed and no mechanical problems are encountered. The FESS consists of a shaft, flywheel, motor/generator, bearings, and case. It is difficult to simulate rotor dynamics using common structure simulation programs because these programs are based on the 3D model and complex input rotating conditions. Therefore, in this paper, a program for the FESS based on the 2D FEM was developed. The 2D FEM can model easier than 3D, and it can present the multi-layer rotor with different material each other. Stiffness changing of the shaft caused by shrink fitting of the hub can be inputted to get clear solving results. The results obtained using the program were compared with those obtained using the common programs to determine any errors.
Optimization of Laser Process Parameters for Realizing Optimal Via Holes for MEMS Devices
Park, Si-Beom ; Lee, Chul-Jae ; Kwon, Hui-June ; Jun, Chan-Bong ; Kang, Jung-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1765~1771
DOI : 10.3795/KSME-A.2010.34.11.1765
In the case of micro.electro-mechanical system (MEMS) devices, the quality of punched via hole is one of the most important factors governing the performance of the device. The common features that affect the laser micromachining of via holes drilled by using Nd:
laser are described, and efficient optimization methods to measure them are presented. The analysis methods involving an orthogonal array, analysis of variance (ANOVA), and response surface optimization are employed to determine the main effects and to determine the optimal laser process parameters. The significant laser process parameters were identified and their effects on the quality of via holes were studied. Finally, an experiment in which the optimal levels of the laser process parameters were used was carried out to demonstrate the effectiveness of the optimization method.
Seismic Evaluation of Structural Integrity of Main Cooling-Water Pump by Response Spectrum Analysis
Chung, Chul-Sup ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1773~1778
DOI : 10.3795/KSME-A.2010.34.11.1773
To evaluate the structural integrity of the main cooling-water pump of a nuclear power plant under different seismic conditions, the seismic analysis was performed in accordance with IEEE-STD-344 code. The finite element computer program, ANSYS, was used to perform both mode frequency analysis and response spectrum analysis for the pump assembly. The natural frequencies, the mode shapes, and the mode participation factors were obtained from the results of the mode frequency analysis. The stresses resulting from various loadings and their combinations were within the allowable limits specified in the above-mentioned IEEE code. The results of the seismic evaluation fully satisfied the structural acceptance criteria of the IEEE code. Thus, it was proved that the structural integrity of the pump assembly was satisfactory.
Development of Novel Net Hauler for Improved Washing of Fishing Nets
Choi, Deok-Ki ; Kim, Yong-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 11, 2010, Pages 1779~1784
DOI : 10.3795/KSME-A.2010.34.11.1779
Net washing in a fishery involves considerable labor and is a time-consuming process; it also causes severe environmental pollution. In this study, we developed a net hauler for washing fishing nets. This hauler can be used to simultaneously haul and wash the net. We devised the revolver structure of the net hauler in order to resolve the net slip problem. The net hauler can be used by itself for washing small-sized nets, or it can be used in an auxiliary washing step in case of a large-sized net. Further, the component installed in the net hauler for unraveling the net improves the net washing performance of an automatic net washer. During the experiments conducted using the prototypes of the new net hauler, the net did not slip and the desired washing performance could be achieved.