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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
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 25, Issue 12 - Dec 2001
Volume 25, Issue 11 - Nov 2001
Volume 25, Issue 10 - Oct 2001
Volume 25, Issue 9 - Sep 2001
Volume 25, Issue 8 - Aug 2001
Volume 25, Issue 7 - Jul 2001
Volume 25, Issue 6 - Jun 2001
Volume 25, Issue 5 - May 2001
Volume 25, Issue 4 - Apr 2001
Volume 25, Issue 3 - Mar 2001
Volume 25, Issue 2 - Feb 2001
Volume 25, Issue 1 - Jan 2001
Selecting the target year
A Study on Determination of
by Time-Frequency Analysis Method
Nam, Gi-U ; An, Seok-Hwan ; Kim, Bong-Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 765~771
DOI : 10.22634/KSME-A.2001.25.5.765
Elastic-plastic fracture toughness JIC can be used a s an effective design criterion in elastic-plastic fracture mechanics. Among the JIC test methods approved by ASTM, unloading compliance method was used in this study. In order to examine the relationship between fracture behavior of JIC test and AE signals, the post processing of AE signals has been carried out by Short Time Fourier Transform(STFT), one of the time-frequency analysis methods. The objective of this study is to evaluate the application of characterization of AE signals for unloading compliance method of JIC test. As a result of time-frequency analysis, we could extract the AE from the raw signal and analyze the frequencies in AE signal at the same time. AE signal generated by elastic-plastic fracture of material has some different aspects at elastic and plastic ranges, or the first portion of crack growth by fracture. First of all, increased energy recorded and detected by using AE count method increase rapidly from the start of ductile fracture. The variation of main frequency range with time-frequency analysis method could be confirmed. We could know fracture behavior of interior material by examination AE characteristics generated in real-time when elastic-plastic fracture occurred in material under loading.
Corrosive Characterisics of 12Cr Alloy Steel and Fatigue Characteristics of the Artificially Degraded 12Cr Alloy Steel
Jo, Seon-Yeong ; Kim, Cheol-Han ; Bae, Dong-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 772~778
DOI : 10.22634/KSME-A.2001.25.5.772
In this study, corrosion fatigue characteristics of 12Cr alloy steel were investigated in 3.5wt.% NaCl solution of 150
and 4.5bar. Behavior of corrosion fatigue cracks was measured by the indirect compliance method and compared with the results in distilled water and in air. 1) 12Cr alloy steel was susceptible to temperature. Its susceptibility was increased as the temperature was increased. 2) The crack growth characteristics of 12Cr alloy steel in distilled water were similar to 3.5wt.% NaCl solution. 3) The temperature of solution affects to the crack growth characteristics of 12Cr alloy steel. In corrosion solutions of 4.5bar, 150
, fracture surfaces of corrosion fatigue crack growth at a/W=0.3 was showed the trans-granular fracture suface. As the crack grew up, it was changed to inter-granular type. In condition of high temperature, The crack growth behaviors of 12Cr alloy steel were remarkable.
A Study on the Optimal Design, Modeling and Control of the Multi d.o.f Precision Positioning System Using Magnetic Levitation Actuating Principle
Jeong, Gwang-Seok ; Baek, Yun-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 779~787
DOI : 10.22634/KSME-A.2001.25.5.779
The multi degree of freedom system using magnetic levitation has been implemented successfully. Differently from another noncontact systems, the developed system was focused on the maximization of the system stiffness under the constraint of a limited input. The variation of a relative adopting point between the magnetic pair, its location on the fixed base, and the selection of optimal specifications for the main active magnetic elements give us another chance to realize the increased robustness against external disturbances with the less control inputs. In this paper, the overall development procedures are given including the optimal design, the dynamic modeling, the various control tests, and the main issues to be solved.
Development of VR Monitoring System for Gas Plant
Seo, Myeong-Won ; Jo, Gi-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 788~796
DOI : 10.22634/KSME-A.2001.25.5.788
VR(Virtual reality) technologies have given engineers the ability to design, test, and evaluate engineering systems in a virtual environment. The virtual plant is the highlight of the application of the VR technology to plant engineering. Plant design, maintenance, control, management, operation are integrated in the virtual plant. The VR monitoring system including the concept of the virtual plant is developed to replace a current control room that has number of gages and warning lamps in two-dimensional panels which shows the operating status of a plant. The operating status of the plant is displayed in the VR monitoring system through the realistic computer graphics. Sophisticated, realistic and prompt control becomes possible. The VR monitoring system consists of advanced visualization, walk-through simulation and navigation. In the virtual environment, a user can navigate and interact with each component of a plant. In addition, the user can access the information by just clicking interesting component. The VR monitoring system is operated with various modules, such as (1) virtual plant constructed with Graphic Management System (GMS), (2) Touch & Tell System, and (3) Equipment DB System of Part. In order to confirm the usefulness of the VR monitoring system, a pilot gas plant which is currently being used for plant operator training is taken as application. The end of the paper gives an outlook on the future work and a brief conclusion.
Evaluation of Fatigue Crack Growth Characteristics Considering Crack Closure Phenomenon in Weldment of Multi-Pass Welded Pipe
Kim, Cheol-Han ; Jo, Seon-Yeong ; Bae, Dong-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 797~804
DOI : 10.22634/KSME-A.2001.25.5.797
To obtain representative fatigue crack growth characteristic curve in residual stress field, fatigue crack growth test was carried out at various stress ratio and fatigue crack growth characteristic curve was represented using crack closure concept. Obtained results are as follows;K(sub)op/K(sub)max was independent of K(sub)max when R was lower than 0.5 and crack closure phenomenon was not observed when R is higher than 0.5. therefore neglecting crack closure behaviour, actual fatigue crack growth rate can be underestimated. Thus, considering crack closure phenomenon, fatigue crack growth characteristics curve of A 106 Gr B Steel weldment can be effectively estimated.
Modeling and Design of an Active Pressure Regulating Valve(Implant)
Bae, Byeong-Hun ; Kim, Nak-Hun ; Lee, Yeon ; Gi, Hong-Seok ; Kim, Seon-Ho ; Park, Gi-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 805~815
DOI : 10.22634/KSME-A.2001.25.5.805
Glaucoma is an eye disease which is caused by abnormal high IOP (Intra Ocular Pressure). High IOP is caused by the aqueous humor which is produced consistently but not drained due to malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are three methods to treat glaucoma-using medicines, surgical operation, and using implant device. The first and second methods are not long acting, so the use of implants is increasing in these days in order to drain out the aqueous humor compulsory. However, though conventional implants have a capability of pressure regulation, they cannot maintain IOPs desired for different patients, and too much aqueous humor are usually drained, to cause hypotony. To solve these problems, it is needed to develop a new implant which is capable of controling the IOP actively and copes with personal difference of patients. An active glaucoma implant consists of the valve actuator, pressure sensor, controller, and power supply. In this paper, firstly, we make an analysis of the operation of a conventional implant using a bond graph and show defects and limitations of the conventional valve analytically. Secondly, we design and analyze a valve actuator considering actuation principles, resistance elements, control methods, and energy sources focused on power saving problem. Finally, using simulations the possibility of the proposed valve actuator is investigated.
The Effect of Gas Absorption Induced a Change of Glass Transition Temperature in Microcellular Foamed Plastics
Hwang, Yun-Dong ; Cha, Seong-Un ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 816~822
DOI : 10.22634/KSME-A.2001.25.5.816
The thermoforming process is widely used in the plastics industry to produce articles for the packaging, automotive, domestic construction and leisure industries. The microcellular foaming process appeared at M.I.T. in 1980s to save a quantity of polymer materials and increase their mechanical properties. The glass transition temperature of polymer materials is one of many important process variables in appling the microcellular foaming process to the conventional thermoforming process. The goal of this research is to evaluate the relation between gas absorption and glass transition temperature in batch process using microcellular foaming process. The weight gain ratio of polymer materials has a conception of gas absorption. Polymers such as acrylonitrile-butadiene-styrene(ABS), polystyrene(PS) have been used in this experiment. According to conventional Chows model and Cha-Yoon model, it was estimated with real experimental result to predict a change of glass transition temperature as a function of the weight gain ratio of polymer materials in batch process to gain microcellular foamed plastic products.
C* Based Life Assessment of 3D Crack at High Temperature
Han, Tae-Soo ; Yoon, Kee-Bong ; Lee, Hyung-Il ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 823~833
DOI : 10.22634/KSME-A.2001.25.5.823
In recent years, the subject of remaining life assessment has drawn considerable attention in chemical plants, where various structural components typically operate at high temperature an pressure. Thus a life prediction methodology accounting for high temperature creep fracture is increasingly needed for the components. Critical defects in such structures are generally found in the form of semi-elliptical surface crack, and the analysis of which is consequently an important problem in engineering fracture mechanics. On this background, we first develop an auto mesh generation program for detailed 3-D finite element analyses of axial and circumferential semi-elliptical surface cracks in a piping system. A high temperature creep fracture parameter C-integral is obtained from the finite element analyses of generated 3-D models. Post crack growth module is further appended here to calculate the amount of crack growth. Finally the remaining lives of surface cracked pipes for various analytical parameters are assessed using the developed life assessment program.
Development and Implementation of Real Time Multibody Vehicle Dynamics Model
O, Yeong-Seok ; Kim, Seong-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 834~840
DOI : 10.22634/KSME-A.2001.25.5.834
A real time multibody vehicle dynamics model has been developed and implemented using a subsystem synthesis method based on recursive formulation. To verify real time simulation capability the developed model has been applied to HMMWV(High Mobility Multipurpose Wheeled Vehicle) with steering system. For the kinematically driven steering system, the coupled front suspension-steering subsystem can be decoupled into two SLA suspension subsystems, which improves the efficiency of simulation. To investigate theoretical efficiency, operational counting method has been also employed to compare the proposed model with the conventional recursive dynamics model. Various simulations such as unsymmetric bump run, step steering(J-turn) and sine steering input test have been carried out to verify the real time feasibility of the proposed model.
Object Recognition Using Hausdorff Distance and Image Matching Algorithm
Kim, Dong-Gi ; Lee, Wan-Jae ; Gang, Lee-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 841~849
DOI : 10.22634/KSME-A.2001.25.5.841
The pixel information of the object was obtained sequentially and pixels were clustered to a label by the line labeling method. Feature points were determined by finding the slope for edge pixels after selecting the fixed number of edge pixels. The slope was estimated by the least square method to reduce the detection error. Once a matching point was determined by comparing the feature information of the object and the pattern, the parameters for translation, scaling and rotation were obtained by selecting the longer line of the two which passed through the matching point from left and right sides. Finally, modified Hausdorff Distance has been used to identify the similarity between the object and the given pattern. The multi-label method was developed for recognizing the patterns with more than one label, which performs the modified Hausdorff Distance twice. Experiments have been performed to verify the performance of the proposed algorithm and method for simple target image, complex target image, simple pattern, and complex pattern as well as the partially hidden object. It was proved via experiments that the proposed image matching algorithm for recognizing the object had a good performance of matching.
Robust Control of the Nonlinear Hydraulic Servo System Using a PID Control Technique
Yu, Sam-Hyeon ; Lee, Jong-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 850~856
DOI : 10.22634/KSME-A.2001.25.5.850
Even though the hydraulic servo system has been widely used in industrial and military equipments since it has a lot of advantages, it is not easy to design controller due to the high nonlinearities and the parametric uncertainties. The dynamic behavior of the real process in the hydraulic servo system differs from that described by its model because the model is linearized. Another reason of the difference is caused by the variety of parameters, since the system parameters of the dynamic equation are affected by the operating conditions such as temperature and pressure. In this study, the designing process of the MRNC with a PID compensator is introduced and applied to the load sensing hydraulic servo system. The results show that the designed controller guarantees the robust control performance despite of both the nonlinearities and the parametric uncertainties.
Thermo-elastic Creep and Frequency Optimization by Using Feasible Direction Method
Jo, Hui-Geun ; Park, Yeong-Won ; Gang, Yeon-Sik ; Lee, Gyeong-Don ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 857~865
DOI : 10.22634/KSME-A.2001.25.5.857
In finite element analysis, engineering optimizations are divided two major parts that are topology and structural optimization. Until these days most structural optimizations usually concentrate on single disciplinary optimization. Therefore numerical analysis and methodology which can optimize thermo-elastic creep and frequency phenomena are not suggested. In this paper finite element analysis methodology and algorithm of thermo -elastic creep and frequency optimizations are suggested and corroborate the efficiency of suggested new numerical methodology and algorithm by solving example problem.
Wave Motion of Helical Springs with a Circular Section
Lee, Jae-Hyeong ; Heo, Seung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 866~873
DOI : 10.22634/KSME-A.2001.25.5.866
The governing partial differential equations of a helical spring with a circular section were derived from Frenet formulas and Timoshenko beam theory. These were solved to give the dispersion relationship between wave number and frequency along with wave form. Wave motions of helical springs are categorized by 4 regimes. In the first regime, the lower frequency area, the torsional and extensional waves of the spring are predominant and two waves are composite wave motions involving lateral motion of the coils and rotation of the coils about a horizontal axis. All waves are propagating in the second regime. The wave of the extensional motion of the spring and one wave of transverse motion of a wire change from travelling waves to near field waves in the third regime. Both waves excited by both axial and transverse motion are predominant in the fourth regime.
A Proposal of Parameter Determination Method in the Residual Strength Degradation Model for the Prediction of Fatigue Life (I)
Kim, Sang-Tae ; Jang, Seong-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 874~882
DOI : 10.22634/KSME-A.2001.25.5.874
The static and fatigue tests have been carried out to verify the validity of a generalized residual strength degradation model. And a new method of parameter determination in the model is verified experimentally to account for the effect of tension-compression fatigue loading of spheroidal graphite cast iron. It is shown that the correlation between the experimental results and the theoretical prediction on the statistical distribution of fatigue life by using the proposed method is very reasonable. Furthermore, it is found that the correlation between the theoretical prediction and the experimental results of fatigue life in case of tension-tension fatigue data in composite material appears to be reasonable. Therefore, the proposed method is more adjustable in the determination of the parameter than maximum likelihood method and minimization technique.
Parallel Processing Based Decompositon Technique for Efficient Collaborative Optimization
Park, Hyeong-Uk ; Kim, Seong-Chan ; Kim, Min-Su ; Choe, Dong-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 883~890
DOI : 10.22634/KSME-A.2001.25.5.883
In practical design studies, most of designers solve multidisciplinary problems with large size and complex design system. These multidisciplinary problems have hundreds of analysis and thousands of variables. The sequence of process to solve these problems affects the speed of total design cycle. Thus it is very important for designer to reorder the original design processes to minimize total computational cost. This is accomplished by decomposing large multidisciplinary problem into several multidisciplinary analysis subsystem (MDASS) and processing it in parallel. This paper proposes new strategy for parallel decomposition of multidisciplinary problem to raise design efficiency by using genetic algorithm and shows the relationship between decomposition and multidisciplinary design optimization (MDO) methodology.
A Study on a Virtual Object Exploration Using a Force Reflection Virtual Teleoperation System
Gwon, Hyeok-Jo ; Kim, Gi-Ho ; O, Jae-Yun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 891~898
DOI : 10.22634/KSME-A.2001.25.5.891
This paper develops a master manipulator which can reflect a force from a slave manipulator effectively. It many have a big workspace, can represent a human operators manipulation perfectly, and is composed of a position control part, an orientation control part and an end effector control part. This paper also develops a graphic simulator using the Visual C++ and OpenGL in the Window operating system. It can be used to make a virtual slave manipulator and set a virtual working environment, and provide a visual information from a desired view point. A virtual teleoperation system is developed by connecting the developed master manipulator to the graphic simulator using an interfacing hardware bilaterally. It is used for performing a virtual object exploration experiment. In the experiment, two virtual objects are used. They are virtual wall and virtual hexahedron which have 0.7N/mm and 2.2 N/mm stiffness respectively. The experiments are performed under six different working conditions. The experiment results will show the effectiveness of the reflected force from the slave manipulator for improving the efficiency and stability of the teleoperation task.
Finite Element Analysis and Experimental Study About Damage Behavior of Glass by Oblique Impact of Steel Ball
Seo, Chang-Min ; Kim, Seong-Ho ; Kim, Dong-Gyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 5, 2001, Pages 899~905
DOI : 10.22634/KSME-A.2001.25.5.899
The damage behavior of soda-lime glass was studied due to a steel ball of 1mm and 2mm at oblique impact test. The thickness of glass specimen were 3mm and 5mm and oblique degrees of impact were 90
. After the steel ball impact test, the crack patterns were investigated using a stereo-microscope. In addition, the finite element method was performed to analyze the stresses distribution and variation in the oblique impacted glass by steel ball. As a result of the impact test, the crack length of 90
impacted glass was the largest and that of 50
impacted glass was the smallest. In particular, as the impact velocity and diameter of the steel ball increased, the difference of crack length was prominent. The finite element analysis showed the maximum principle stresses distribution in contact area of glass specimen. The result of analysis was accorded with the crack growth behavior by the oblique impact test.