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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
Editor in Chief :
Volume & Issues
Volume 20, Issue 12 - Dec 1996
Volume 20, Issue 11 - Nov 1996
Volume 20, Issue 10 - Oct 1996
Volume 20, Issue 9 - Sep 1996
Volume 20, Issue 8 - Aug 1996
Volume 20, Issue 7 - Jul 1996
Volume 20, Issue 6 - Jun 1996
Volume 20, Issue 5 - May 1996
Volume 20, Issue 4 - Apr 1996
Volume 20, Issue 3 - Mar 1996
Volume 20, Issue 2 - Feb 1996
Volume 20, Issue 1 - Jan 1996
Selecting the target year
Development of Precision Inspection Technique for Aircraft Parts Having Very Thin Features on CAD/CAI Integration
Park, Hui-Jae ; An, U-Jeong ; Kim, Wang-Do ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1743~1752
DOI : 10.22634/KSME-A.19220.127.116.113
In this paper, a precision inspection technique using CAD/CAI integration is proposed for the parts having very thin and sharp 3 dimensional curve features. The technique begings with feature reconstruction of turbine blades which have 3 dimensional combined feometry, such as splines, and thin circles. The alifnment procedures consistsb of two phases-rough and fine phases : rough phase alignment is based on the conventional 6 point5s probing on the clear cut surfacef, and fine phase alignment is based on the intial measurement on the 3 dimensional curved parts using an lterative measurement feed-back least sequares technique for alignment. Forf the analysis of profile tolerance of parts, the actual measured points are obtained by finding the closet points on the CAD geometry by the developed subdivision technique and the Tschebycheff norm is applied based on iterative fashion, giving accurate profile tolerance value. The developed inspection technique is applied to practical procedures of blade manufacturing and demonstrated high performance.
Wear Behaviors of
under Various Sliding Conditions
Lee, Yeong-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1753~1761
DOI : 10.22634/KSME-A.1918.104.22.1683
The wear behaviors of
under the different sliding conditions were investigated. The cylinder-on-disc wear tester was used. Using the servo-metor, the sliding speed did ot alternate due to the frictional forces. Threekinds of loads and speeds were selected to watch the variation of the wear rates and the frictional forces. Also three kinds of sliding condition under a constant speed were used to see the effects of the oxidationand the abrasion. The contact pressure was more effective than the repeated cycle on the wear behavior of
. With the low loads, the effect of the asperity-failure was more dominant than that of oxidation and abrasion. As increasing the load, the effects of oxidation and abrasion were increased, but the asperity-failure effects were decreased. The wear particles destroyed the ozide layers formed on sliding surfaces. The wear rate could be decreased due to delaying the oxidation. The frictional power and the wear weight per time were usefuel to see the transition of wear.
Kinematic Optical Design of an Open-Close Type Gripper Mechanism
Kim, Whee-Kuk ; Park, Joo-Young ; Yoon, Seong-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1762~1772
DOI : 10.22634/KSME-A.1922.214.171.1242
The main objective of this study is to develop a gripper mechanixm that can be employed for assembly and removal tasks of a nozzle-dam of steam genetator in the process of the nuclear reactor maintenances. Brief description of the open-close thpe gripper mechanism, its position analysis, and its kinematic analysis are given. The optimal design of the gripper mechanism with and without slipping on its two gipping surfaces is considered. As an optimal design index, the ratio of the actuator force of prismatic cylinder to gripping load is proposed. Then, based on this index the oiptimal design is carried out to identify values of optimal design parameters for the gripper dechanism.
Dynamic Analysis of the Structures under Dynamic Distributed Loads Using Spectral Element Method
Lee, U-Sik ; Lee, Jun-Geun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1773~1783
DOI : 10.22634/KSME-A.19126.96.36.1993
Finite element method(FEM) is one of the most popularly used method analyzing the dynamic behaviors of structures. But unless number of finite elements is large enough, the results from FEM some what different from exact analytical solutions, especially at high frequency range. On the other hand, as the spectral analysis method(SAM) deals directly with the governing equations of a structure, the results from this melthod cannot but be exact regardless of any frequency range. However, the SAM can be applied only to the case where a structure is subjected to the concentrated loads, despite a structure could be unddergone distributed loads more generally. In this paper, therefore, new spectral analysis algorithm is introduced through the spectral element method(SEM), so that it can be applied to anlystructures whether they are subjected to the concentrated loads or to the distributed loads. The results from this new SEM are compared with both the results from FEM and the exact analytical solutions. As expected, the results from new SEM algorithm are found to be almost identical to the exact analytical solutions while those from FEM are not agreed well with the exact analytical solutions as the mode number increases.
Stress Analysis of Fir-Tree Root in Turbine Rotor Using Photoelastic Technique
Sin, Gwang-Bok ; Gyeong, U-Min ; Hong, Chang-Seon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1784~1797
DOI : 10.22634/KSME-A.19188.8.131.524
The disk/blade assembly of a turbine engine is made in the shape of a dovetail type or a fir-tree type. Since disk fillet regions or contact surfaces undergo high stress comcentration, fatigue cracks frequentrly occur in the disk/blade assembly. Therefore, it is necessary to analyze the stress distributions in the fir-tree type disk/balde assembly and predict the region of fatigue failure. The stress distributions of the disk/blade assembly were investigated by using the photoelastic method and the finite element method. Two dimensional photoelastic techniques were used to investigate the stress distributions of contact surfaces and fillet regions. TH stress distributions were obtained by the shear-difference method and were compared to the finite element results. It was found that maximum tensile stresses were higher in the fillet region thatn in the contact surfaces of the fir-tree models. The finite element results showed good agreement with the experimental results.
Development of New Z-Factor for the Evaluation of Circumferential Surface Crack In Ferristic Steel Pipings
Choi, Yeong-Hwan ; Chung, Yeon-Ki ; Lee, Jeong-Bae ; WilkowsKi, Gery ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1798~1809
DOI : 10.22634/KSME-A.19184.108.40.2068
The purpose of this paper is to develop new Z-Factors to evaluate the behavior of circumferential surface crack in ferritic steel piping including base metal and Submerged Arc Weld(SAW) metal in nuclear power plant. The Z-factor is a load multiplier to convert plastic load to elasto-plastic load. However the current Z-Factor is a load multiplier to convert plastic load to elasto-plastic load. However the current Z-Factor gives too conservative results. In this study, a J-estimation method, SC.TNP method, which is based on GE/EPRI expression, is used to develop new Z-Factors. The desirabilities of both the SC.TNP mehtod and the new Z-Factors are examined using the previous experimental results for the circumferential surface crack in ferritic steel pippings. The results are as follows ; (1) The SC.TNP mehtod is good for describing the circumferential surface crack behavior in farritic steel pipings, while the well-known R6 mehtod and DPFAD method give too conservative results. (2) The ASME-Z-Factor method using nwe Z-Factors well predicts the behavior of circumferential surface crack in ferritic steel pipings including base emtal and SAW metal.
Blank Design and Strain Prediction in Sheete Metal Forming Process
Lee, Choong-Ho ; Huh, Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1810~1818
DOI : 10.22634/KSME-A.19220.127.116.110
A new finite elemetn approach is introduced for direct prediction of bland shapes and strain distributions from desired final shapes in sheet metal forming. The approach deals with the geometric compatibility of finite elements, plastic deformation theory, minimization of plastic work with constraints, and a proper initial guess. The algorithm developed is applied to cylindrical cup drawing, square cup drawing, and fron fender forming to confirm its validity by demonstratin reasonable accurate numerical results of each problems. Rapid calculation with this algorithm enables easy determination of various process variables for design of sheet metal forming process.
Optimum Field Balancing of Ratating Machinery Using Genetic Algorithm
Choi, Won-Ho ; Yang, Bo-Suk ; Joo, Ho-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1819~1826
DOI : 10.22634/KSME-A.1918.104.22.1689
This paper present the claculating method of optimum correction mass within permissible vibration linits for ratating machinery in two-plane field balancing. Basic technique of this method is based on influence coefficient method, and grphic vector composition that the resultant of two influence vectors obtained by trial mass have to be equilibrium with initial vibration vector in the each correction plane. Genetic algorithm which is a search algorithm based on the mechanism of natural selection and natural genetics is sued for vector composition, and SUMT method is used to objective function which seeks optimum correction mass for balancing a rotor.
A Study on Torch Path Generation for Laser Cutting Process
Han, Guk-Chan ; Na, Seok-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1827~1835
DOI : 10.22634/KSME-A.1922.214.171.1247
This paper addresses the problem of a torch path generation for the 2D laser cutting of a stock plate nested with resular or irregular parts. Under the constaint of the relative positions of parts enforced by nesting, the developed torch path algorithm generate feasible cutting path. In this paper, the basic object is a polygon( a many-slide figure) with holes. A part may be represented as a number of line segments connected end-to-end in counterclockwise order, and formed a closed contour as requied for cutting paths. The objective is to tranverse this cutting contours with a minimum path length. This paper proposes a simulated annealing based dtorch path algorithm, that is an improved version of previously suggested TSP models. Since everypiercing point of parts is not fixed in advance, the algorithm solves as relazed optimization problem for the constraint, thich is one of the main features of the proposed algorithm. For aolving the torch path optimization problem, an efficient generation mechanism of neighborhood structure and as annealing shedule were introduced. In this way, a global solution can be obtained in a reasonable time. Seveeral examples are represented to ilustrate the method.
Damage Behavior and Residual Bending Fatigue Strength of CFRP Composite Laminates Subjected to Impact Loading
Im, Kwang-Hee ; Yang, In-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1836~1842
DOI : 10.22634/KSME-A.19126.96.36.1996
In this paper, static and fatigue bending strengths of CFRP(carbon fiber reinforced plastic laminates having impact damage(FOD) are evaluated. Composite laminates used for this experiment are CF/EPOXY and CF/PEEK orthotropy laminated plates, which have two-interfaces[
. A steel ball launched by the air gun colides against CFRP laminates to generate impact damages. The damage growth during bending fatigue test is observed by the scanning acoustic microscope(SAM). When the impacted side is compressed, the residual fatigue bending strength of CF/PEEK specimen P is greater that that of CF/EPOXY SPECIMEN B. On the other hand, when the impacted side is in tension, the residual fatigue bending strength of CF/PEEK speicemen P is smaller than that of CF/EPOXY specimen B. In the case of impacted-side compression, fracture is proposed from the transverse crack generated near impact point. On the other hand, fracture is developed toward the impact point from the edge of interface-b delamination in the case of impacted-side tension.
Crack Stability Evaluation of Nuclear Main Stream Pipe Considering Load Reduction Effect
Koh, Bong-Hwan ; Kim, Yeong-Jin ; Seok, Chang-Seong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1843~1853
DOI : 10.22634/KSME-A.19188.8.131.523
The objective of this paper is to evaluate the crack stability of the nuclear main stresm pipes, considering the load reduction effect due to the presence of circumferential throuth-wall crack. Also, the optimization techniques are adoped tosimulate the crack effect on the elbow component of the piuping system. By using a general beam elemetn which contains a discontinuous cross-section, the piping analysis is accomplished to acquire the reduced load. Considering this reduced load, it is feasible for the LBB application in nuclear main stresm pipe. Also, by combining an optimization program and a genaral finite element analysis program, the appropriate dimensions of the simplified beam elemtn which represents the effect of crack in elbow could be successfully determined.
Finite Element Modeling and Experimental Verification of the Structures with Bolted Joints
Kim, Jin-Gon ; Park, Seong-Su ; Choe, Seok-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1854~1861
DOI : 10.22634/KSME-A.19184.108.40.2064
A reliable and practical finite element modeling technique to estimate the behavior of complex structures with bolted joints is important for engineeres in the industry. Accordingly, we have examined several simplified modeling techinques which do not require the use of special elements such as a gap eloement. The dynamic and static erxperiments have confirmed that the technique to model the bolted joints with eight-noded three dimensional elemnts which fill the bolt space gdives most satisfactory results.
Modification of Current Leak Before Break Criteria for Nuclear Piping System
Yu, Yeong-Jun ; Kim, Yeong-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1862~1871
DOI : 10.22634/KSME-A.19220.127.116.112
The puopose of this paper is sto modify the current LBB criteria. The validity of current LBB criteria and current standard LBB analysis mehtod are evaluated using linear elastic fracture mechanics and elastic-plastic fracture mechanics. The results of evaluation demonstrate that the current LBB driteria are very conservative and some level of margins already exist in the standard LBB analysis method. Thus, the margin on load .root. and margin on crack size 2 can be eliminated to extend LBB application for the samller diameter pipe.
Effect of Nozzle on LBB Evaluation for Small Diameter Nuclear Piping
Yu, Yeong-Jun ; Kim, Yeong-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1872~1881
DOI : 10.22634/KSME-A.1918.104.22.1682
LBB(Leak-Before-Break) analysis is performed for the highest stress location of each different type of mateerials in the nuclear piping line. In most cases, the highest stress occurs in the pipe and nozzle interface location. i.e. terminal end. The current finite element analysis approach utilizes the symmetry condition both for locations near the nozzle and for locationa away from the nozzle to minimize the size of the finite element model and to make analysis simple when calculating the J-integral values at the crack tip. In other words, the nozzle is not included in the finite element model. However, in reality, the symmetric condition is not applicable for the pipe-nozzle interface location. Because the pipe-nozzle interface location is asymmetric due to different stiffenss of the pipe and nozzle(both material and dimensions). The simplified analysis approach for pipe-nozzle interface locaiton is too conservative for a smaller diameter piping. In tlhis paper, various analyses are performed for the range of materials and crack sizes to evaluate the nozzle effect for a LBB anlaysis. This paper presents methodology for developing the piping evaluaiton diagram at the pipe-nozzle interface location.
Robust Control of the Position of a Manipulator Using Pneumatic Artificial Muscle
Park, No-Cheol ; Yang, Hyun-Seok ; Park, Young-Pil ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1882~1892
DOI : 10.22634/KSME-A.1922.214.171.1242
This paper is concerned with the position control of the ond degree-of freedom manipulator using pneumatic artificial muscle actuator which is built to have a proper compliance. For t his pneumatic artificial muscle actuator though, it is difficult to make an effective control scheme due to the nonlinearity and uncertainties on the dynamics of the actuator. In this paper, a third-order equation of motion is derived for the actuator including the dynamics of the pneumatic servovalve. Later, various modeling uncertainties due to the nonlinearity and unmodeled dynamics of the servo vlave and the actuator are taken care of, as a trade-off between the closed-loop performance of the controlled system and its robustness to uncertainties. A controller using .mu. synthesis thchnique is designed, and robust performance against measurement noise, various modeling uncertainties due to the dynamics of the servo valve and actuator is achieved. The effectiveness of the proposed control methods is illustrated through simulations and experiments.
Analysis for Cold Die Compaction of Meteal Powder
Gwon, Yeong-Sam ; Lee, Hui-Tae ; Kim, Gi-Tae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1893~1902
DOI : 10.22634/KSME-A.19126.96.36.1993
Densification behavior of 316L stainless steel power under die pressing was studied. The efects of friction between the powder and die wall under different die pressing modes were also investigated. The elastoplastic constitutive equations based on the yield functions of Fleck-Gurson and of Shima and Oyane were implemented into finite element program(ABAQUS) to simulate die compaction processes. The finite element results were compared with experimental data for 316L stainless steel powder under die pressing.
An Experimental Study on Damage Mechanism of Glass Resulting Frojm Particle Impact
Seo, Chang-Min ; Sin, Hyeong-Seop ; Hwang, Byeong-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1903~1912
DOI : 10.22634/KSME-A.19188.8.131.523
A quantitative study of impact damage of a soda-lime glass was carried out. An initiation and a propagation of cracks by the impact of two inds of steel ball was investigated. The fron, side and rear view of cracks were observed by a stereo-microscope. And the lowering of the benidng strength due to the impact of steel balls was examined through the 4-point bending test. A transparent glass is very helpful to understand and analyze the impact damage behavior of another brittle matereial. A deagdram about crack patterns according to the threshold impact velocity was sketched. A ring crack and a cone crack were formed at the low impact velocity. And as the impact velocity was higher, initial lateral crack was generated on the slanting surface of cone crack, and radial cracks were generated from the outermost ring crack. When the impact velocity of steel balls exceed a critical velocity, the contact site of specimens were crushed. According to the propagation of a cone crack, a rapid strength degradation occurred. In the specimen having crushed region, a bending strength was converged to a constant value instead of strength degradation.
Study on the Development for Low Noise Indoor and Outdoor Package Air-Conditioner
Kim, Jang-Kweon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 20, issue 6, 1996, Pages 1913~1920
DOI : 10.22634/KSME-A.19184.108.40.2063
The purpose of this study was to reduce the airborne noise emitted from the package air-conditioner(PAC) therefore, the optimim design melthods of the fans and the flow-paths were investigated experimentally through the anlaysis of the nose problems caused by the conventional PAC system, and the fan performance tests and the systme resistance measurements of the parts which belong to the flow-paths of the PACwere used to study these noise problems. As a results, through the optimized flow-paths of the new PAC system with the lowset system resistance, and by adjusting and matching the operating point of each fan to each PAC system, the airborne noise reductions from the new indoor PAC and the outdoor one were achieved upto 5.5 dBA and 6.6 dBA respectively in overall noise level as compared with the conventional PAC system.