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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 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
Establishment of Fracture Criteria for Mixed Mode in Bonded Dissimilar Materials with an Crack Emanating from an Edge Semicircular Hole
Jeong, Nam-Yong ; Song, Chun-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 907~915
DOI : 10.22634/KSME-A.2001.25.6.907
Application of bonded dissimilar materials in many industries are increasing. When these materials are to be used in structures, it needs to evaluate the failure strength applying fracture mechanics. Al/Epoxy bonded dissimilar materials with an interface crack and an interface crack emanating from an edge semicircular hole were prepared, experiment of fracture toughness were carried out. Stress intensity factors of interface cracks in bonded dissimilar materials were computed with boundary element method(BEM) and the fracture criteria of mixed mode crack were analyzed. From the results, the fracture criteria and the method of strength evaluation by the fracture toughness in Al/Epoxy bonded dissimilar materials were proposed.
A Lubrication Performance Analysis of Mechanical Face Seals Using Galerkin Finite Element Method
Choe, Byeong-Ryeol ; Lee, An-Seong ; Choe, Dong-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 916~922
DOI : 10.22634/KSME-A.2001.25.6.916
A mechanical face seal is a tribo-element intended to control leakage of working fluid at the interface between a rotating shaft and its housing. Leakage of working fluid decreases drastically as the clearance of the mating seal faces gets smaller. But the very small seal clearance results in an increased reduction of seal life because of high wear and heat generation. Therefore, in the design of mechanical face seals a compromise between low leakage and acceptable seal life is important, and it presents a difficult and practical design problem. A fluid film or sealing dam geometry of the seal clearance affects seal lubrication performance very much, and thereby it is one of the main design considerations. In this study the Reynolds equation for the sealing dam of mechanical face seals is numerically analyzed, using the Galerkin finite element method, which is readily applied to various seal geometries. Film pressures of the sealing dam are analyzed, including the effects of the seal face coning and tilt. Then, lubrication performances of the seals, such as opening forces, restoring moments, leakage, and dynamic coefficients, are calculated, and they are compared to the results obtained by the narrow seal approximation.
Development of Simulator for Performance Test of Electric Power Steering of Light Weight Vehicle
Han, Chang-Su ; Lee, Myeong-Ho ; Park, Ho ; O, Jae-Eung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 923~929
DOI : 10.22634/KSME-A.2001.25.6.923
Steering system is most important for vehicle in safety and driving feel. However, testing using real car to improve steering feel is often difficult in aspect to repeatability, safety and money. Repeatability in testing steering system is very important because steering feel for driver is variable according to the environment condition. And steering testing of vehicle is so dangerous that driver may not concentrate in testing. In this paper, the steering system simulator using front part of steering and suspension system was developed. We can test the electric power steering system for the light weight vehicle using this simulator cheap, safely and repeatably.
A Study on Friction and Wear Behavior of Carbon Fiber Reinforced Polyetheretherketone
Ryu, Seong-Guk ; Kim, Gyeong-Ung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 930~937
DOI : 10.22634/KSME-A.2001.25.6.930
The friction and wear behavior of short carbon fiber reinforced polyetheretherketone was studied experimentally under dry sliding conditions against SCM440(AISI 4140) disks with different surface roughness and hardness at the low sliding speeds and the high pressures on a pin-on-disk apparatus. Under the low disk surface roughness value the earsplitting noise and stick-slip were occurred. The increased adhesion friction and wear factor with stick-slip made the friction and wear behavior worse. Under the high disk surface hardness the break and falling-off of carbon fibers were accelerated. The carbon fibers fallen off from the matrix were ground into powder between two wear surfaces and this phenomenon caused abrasive friction and wear factor to increase. So the friction and wear behavior became worse. With the transfer film made of wear particles formed on a disk, the carbon powder film formed on a pin lowered a friction coefficient.
Hand Exoskeleton with PWM Driving Method
Choe, Byeong-Hyeon ; Choe, Hyeok-Ryeol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 938~948
DOI : 10.22634/KSME-A.2001.25.6.938
In this paper, we present an exoskeletal haptic device named SKK Hand Master. This device is directly driven linkages actuated with small ultrasonic motors. By adopting ultrasonic motors that have advantageous features useful for cybernetic actuators, a compact haptic device containing whole driving packages can be established without additional power transmissions such as tendons. Methods for measuring joint postures and joint torques are developed and a new control strategy called PWM/PS is proposed to overcome intrinsic disadvantages such as hysteresis. Issues regarding design and construction of the device are addressed and several results of experiments for the evaluations of performance are included.
Dynamic Interfacial Crack in Bonded Anisotropic Strip Under Out-of-Plane Deformation
Park, Jae-Wan ; Choe, Seong-Ryeol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 949~958
DOI : 10.22634/KSME-A.2001.25.6.949
A semi-infinite interfacial crack propagated with constant velocity in two bonded anisotropic strips under out-of-plane clamped displacements is analyzed. Using Fourier integral transform the problem is formulated and the Wiener-Hopf equation is derived. By solving this equation the asymptotic stress and displacement fields near the crack tip are obtained, where the results get more general expressions applicable not only to isotropic/orthotropic materials but also to the extent of the anisotropic material having one plane of elastic symmetry for the interfacial crack. The dynamic stress intensity factor is obtained as a closed form, which is decreased as the velocity of crack propagation increases. The critical velocity where the stress intensity factor comes to zero is obtained, which agrees with the lower value between the critical values of parallel crack merged in the material 1 and 2 adjacent to the interface. Using the near tip fields of stresses and displacements, the dynamic energy release rate is also obtained as a form of the stress intensiy factor.
Microfabrication of Microwave Transceivers for On-Chip Near-Field Electromagnetic Shielding Characterization of Electroplated Copper Layers
Gang, Tae-Gu ; Jo, Yeong-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 959~964
DOI : 10.22634/KSME-A.2001.25.6.959
An experimental investigation on the near-field electromagnetic loss of thin copper layers has been presented using microfabricated microwave transceivers for applications to multi-chip microsystems. Copper layers in the thickness range of 0.2
m have been electroplated on the Pyrex glass substrates. Microwave transceivers have been fabricated using the 3.5mm
3.5mm nickel microloop antennas, electroformed on the silicon substrates. Electromagnetic radiation loss of the copper layers placed between the microloop transceivers has been measured as 10dB∼40dB for the wave frequency range of 100MHz∼1GHz. The 0.2
m-thick copper layer provides a shield loss of 20dB at the frequencies higher than 300MHz, whereas showing a predominant decreases of shield loss to 10dB at lower frequencies. No substantial increase of the shield effectiveness has been found for the copper shield layers thicker that 2
Corrosive Characterisics of 12Cr Alloy Steel and Fatigue Characteristics of the Artificially Degraded 12Cr Alloy Steel
Jo, Sun-Young ; Kim, Chul-Han ; Bae, Dong-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 965~971
DOI : 10.22634/KSME-A.2001.25.6.965
To estimate the reliability of 12Cr alloy steel, the material of turbine blade in the steam power plant, Its corrosion susceptibility and fatigue characteristics in NaCl and Na
solution with the difference of concentration and temperature was investigated. The polarization tests recommended in ASTM G5 standard for corrosion susceptibility in the various corrosive solutions was estimated. It showed that the higher temperature, the faster corrosion rates and corrosion rates were the fastest in 3.5 wt.% NaCl and 1M Na
solution. From these results, the degradation conditions were determined in distilled water, 3.5 wt.% NaCl and 1M Na
solution at room temperature, 60
during 3, 6 and 9 months. Its surface had a few pits for long duration. But, it was not susceptible in sulfide and chloride condition of several temperatures. If the degraded 12Cr alloy steel and non-degraded one were compared with fatigue characteristics, Any differences were not found regardless of temperature and degradation period.
Prediction of the Amount of Tool Fracture in Face Milling Using Cutting Force Signal
Kim, Gi-Dae ; Ju, Jong-Nam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 972~979
DOI : 10.22634/KSME-A.2001.25.6.972
Tool fracture index(TFI) was developed in order not only to detect tool fracture but also to predict the amount of tool fracture in face milling. TFI is calculated by using peak-to-valley values of cutting force acting on teeth and their ratio between the adjacent teeth. When the tool fractures, a large value of TFI proportional to the amount of tool fracture was obtained periodically and decreased gradually. It was found that TFI is independent of cutter runout and it almost does not vary during transient cutting such as cutting condition change during machining. The threshold of tool fracture can be analytically determined by TFI developed in this paper, because the magnitude of TFI was shown to be dependent on the ratio of the amount of tool fracture to feed per tooth and immersion ratio. It was possible to predict the amount of tool fracture in experiments by using the proposed TFI.
Finite Element Analysis for the Variation of Carcass Tension Distribution to the Sidewall-Radius Change
Jo, Jin-Rae ; Jeong, Hyeon-Seong ; Lee, Hong-U ; Kim, Nam-Jeon ; Kim, Gi-Un ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 980~987
DOI : 10.22634/KSME-A.2001.25.6.980
Tire performance is significantly influenced by the carcass tension distribution that is governed by the sidewall contour. To maximize the tire performance, it is very important for one to find the sidewall contour with the ideal tension distribution. But it is not easy to find such an optimal sidewall contour. Therefore, in order for a successful tire-shape optimization, we need to investigate how the change of sidewall radius influences on the carcass tension distribution. In this paper, we intend to numerically investigate the relation between the sidewall-radius change and the carcass tension distribution.
Study on the Volume Fraction Optimization of Functionally Graded Heat-Resisting Composites
Jo, Jin-Rae ; Ha, Dae-Yul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 988~995
DOI : 10.22634/KSME-A.2001.25.6.988
Functionally graded materials(FGMs) are highlighted to be suitable for high temperature engineering due to their continuous distribution of material properties. In this paper, an optimal design is executed for determining the optimal material volume distribution pattern that minimizes the steady-state thermal stress of FGM heat-resisting composites. The interior penalty function method and the golden section method are employed as optimization techniques while the finite element method is used for thermal stress analysis. Through numerical simulations we suggest the volume fraction distributions that considerably improve initial thermal stress distributions.
Fatigue Fracture Characteristics by Corrosion Degradation of 12Cr Alloy Steel
Jo, Seon-Yeong ; Kim, Cheol-Han ; Bae, Dong-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 996~1003
DOI : 10.22634/KSME-A.2001.25.6.996
In order to investigate the fatigue fracture characteristics by corrosion degradation of 12Cr alloy steel, both the fatigue characteristics in air of them artificially degraded during long period and the corrosion fatigue characteristics were experimentally evaluated in various environments which were determined from electro-chemical polarization tests. And also, their fracture mechanisms were analyzed and compared, fractographyically. From their results, the fracture mechanical characteristics of it artificially degraded during long period in the distilled water, 3.5 wt.% NaCl solution and 12.7wt.%(1M) Na
solution of 25, 60 and 90
did not show distinguishable difference comparing with non-corroded one in regardless of temperature and degradation period. It means that degradation of the material by just surface corrosion does not remarkably affect to fatigue crack growth. On the other hand, the crack growth rates by corrosion fatigue increased due to activity increase of corrosive factors such as OH(sub)-,Cl(sup)- and SO
(sup)- at the crack tip with temperature increase. Therefore, the crack growth rates by corrosion fatigue were more faster than that in air of the artificially degraded specimen due to the such difference of crack growth mechanism.
Development of Algorithm for 2-D Automatic Mesh Generation and Remeshing Technique Using Bubble Packing Method (I) -Linear Analysis-
Jeong, Sun-Wan ; Kim, Seung-Jo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 1004~1014
DOI : 10.22634/KSME-A.2001.25.6.1004
The fully automatic algorithm from initial finite element mesh generation to remeshing in two dimensional geometry is introduced using bubble packing method (BPM) for finite element analysis. BPM determines the node placement by force-balancing configuration of bubbles and the triangular meshes are made by Delaunay triangulation with advancing front concept. In BPM, we suggest two node-search algorithms and the adaptive/recursive bubble controls to search the optimal nodal position. To use the automatically generated mesh information in FEA, the new enhanced bandwidth minimization scheme with high efficiency in CPU time is developed. In the remeshing stage, the mesh refinement is incorporated by the control of bubble size using two parameters. And Superconvergent Patch Recovery (SPR) technique is used for error estimation. To verify the capability of this algorithm, we consider two elasticity problems, one is the bending problem of short cantilever beam and the tension problem of infinite plate with hole. The numerical results indicate that the algorithm by BPM is able to refine the mesh based on a posteriori error and control the mesh size easily by two parameters.
Development of Nuclear Piping Integriry Expert System (II) -System Development and Case Studies-
Jeon, Hyeon-Gyu ; Heo, Nam-Su ; Kim, Yeong-Jin ; Park, Yun-Won ; Choe, Yeong-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 1015~1022
DOI : 10.22634/KSME-A.2001.25.6.1015
The objective of this paper is to develop an expert system called NPIES for nuclear piping integrity. This paper describes the structure and the development strategy of the NPIES system. The NPIES system consists of 3 part; the data input part, the analysis part and the output part. The data input part consists of the material properties database module and the suer interface module. The analysis part consists of the LEFM, CDFD, J/T, limit load modules and the 12 analysis routines for different cracks and loading conditions are provided respectively. Analysis results are presented to screen, printer and text file in the output part. Several case studies on circumferentially cracked piping were performed to evaluate the accuracy and the usefulness of the code. Maximum piping loads predicted by the NPIES system agreed well with those by the 3-dimensional finite element analysis. In addition, even if the material properties were not fully given, the NPIES system provided reasonable evaluation results with the predicted material properties inferred from the material properties database module.
Effects of Short-fiber End Shape on Tensile Properties of Reinforced Rubber
Ryu, Sang-Ryeol ; Lee, Dong-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 25, issue 6, 2001, Pages 1023~1030
DOI : 10.22634/KSME-A.2001.25.6.1023
The tensile properties of short nylon6 fiber reinforced NR and SBR have been investigated as functions of diameter ratio(DR), interphase condition, fiber aspect ratio(AR), and fiber content. The short-fiber(DR=3 and AR=2) reinforced SBR did not show the dilution effect for all interphase conditions. And the short-fiber(DR=3 and AR=2) reinforced NR did not show the dilution effect except for the no-coating. The better interphase condition, the lower dilution effect at same DR. The tensile moduli are significantly improved due to fiber content and diameter ratio at same interphase condition. The pull-out force increased with the DR. The better interphase condition, the higher pull-out force at same DR. It is found that the DR and AR have an important effect on tensile properties.