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 27, Issue 12 - Dec 2003
Volume 27, Issue 11 - Nov 2003
Volume 27, Issue 10 - Oct 2003
Volume 27, Issue 9 - Sep 2003
Volume 27, Issue 8 - Aug 2003
Volume 27, Issue 7 - Jul 2003
Volume 27, Issue 6 - Jun 2003
Volume 27, Issue 5 - May 2003
Volume 27, Issue 4 - Apr 2003
Volume 27, Issue 3 - Mar 2003
Volume 27, Issue 2 - Feb 2003
Volume 27, Issue 1 - Jan 2003
Selecting the target year
Analysis and Design of Constant-Force Mechanisms Using a Linear Spring
Kim, Whee-Kuk ; Kim, Hae-Soo ; Kim, Min-Gun ; Yi, Byung-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 215~222
DOI : 10.3795/KSME-A.2003.27.2.215
In this paper, kinematic analysis and design of constant force mechanisms which employ a linear spring are studied. Firstly, sufficient conditions for the mechanisms to be the constant force mechanisms are derived in terms of displacement variables through the kinematic analysis. Secondly, a few conceptual mechanisms satisfying these constraints are proposed.
On a Method for the Durability Enhancement of Plastic Spur Gear Using Finite Element Analysis
Kim, Choong-Hyun ; Ahn, Hyo-Sok ; Chong, Tae-Hyong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 223~230
DOI : 10.3795/KSME-A.2003.27.2.223
Stress patterns are created in the plastic spur gear tooth body by introducing a hole or a steel pin to improve stress distribution. Static analysis using finite element method is carried out to show the effect. The result shows that maximum stress as well as tooth tip displacement is dependent on the size and location of a hole or a steel pin. When a hole located on the tooth center line, the maximum static stress level and the tooth tip deflection is always higher than that of a solid gear. But, a considerable reduction in the maximum stress and tooth tip displacement is achieved by insertion of steel pin.
A Study on the Mechanical Properties of Nuclear Fuel Cladding Materials
Bae, Bong-Kook ; Song, Chun-Ho ; Seok, Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 231~238
DOI : 10.3795/KSME-A.2003.27.2.231
The fuel of light water reactor is used for several years under high temperature and pressure, so it needs to be clad with high corrosion resistance material. The cladding materials must have the characteristics of low absorption of a neutron and high corrosion resistance. Zircaloy-2 in Boiling Water Reactor, Zircaloy-4 in Pressurized Water Reactor have been used as cladding materials and Zirlo has been developed as the material for preventing the corrosion. If the fracture of the cladding tube occurs during operation, it will cause the economic loss to shut down and replace the system. So it is needed to evaluate the integrity of the cladding materials. In this paper, the tensile characteristics of the cladding materials were investigated for the basic research of fracture characteristics. Also the residual stress was analyzed to compare the tube type(original type) specimen and the flattened type specimen.
New Engineering J and COD Estimation Methods for Axial Through-Wall Cracked Pipes
Huh, Nam-Su ; Park, Young-Jae ; Kim, Yun-Jae ; Kim, Young-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 239~246
DOI : 10.3795/KSME-A.2003.27.2.239
This paper proposes engineering estimation equations of elastic-plastic J and COD fur axial through-wall cracked pipes under internal pressure. Based on detailed 3-D FE results based on deformation plasticity, the plastic influence functions for fully plastic J and COD solutions are tabulated as a function of the mean radius-to-thickness ratio, the normalized crack length. and the strain hardening. Based on these results, the GE/EPRI-type J and COD estimation equations are proposed and validated against the 3-D FE results based on deformation plasticity. For more general application to general stress-strain laws or to complex loading, the developed GE/EPRI-type solutions are re-formulated based on the reference stress concept. Such a reformulation provides simpler equations for J and COD, which are then further extended to combined internal pressure and bending. The proposed reference stress based J and COD estimation equations are compared with elastic-plastic 3-D FE results using actual stress-strain data for Type 316 stainless steels. The FE results for both internal pressure cases and combined internal pressure and bending cases compare very well with the proposed J and COD estimations.
Influence of Spring Dynamics and Friction on Dynamic Responses in a Spring-Driven Cam
Ahn, Kil-Young ; Kim, Soo-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 247~254
DOI : 10.3795/KSME-A.2003.27.2.247
The paper presents the influence of spring dynamics and friction on dynamic responses in a spring-driven cam system. The characteristics of the friction on the camshaft are analyzed using the nonlinear pendulum experiment while the parameters of the friction model are estimated using the optimization technique. The analysis reveals that the friction of the camshaft depends on stick-slip, Stribeck effect and viscous damping. Spring elements are found to have much influence on the dynamic characteristics. Hence, they are modeled as four-degree-of-freedom lumped masses with equivalent springs. The appropriateness of the derived friction model and spring model is verified by its application to a vacuum circuit breaker mechanism of the cam-follower type.
Evaluation on Material Properties of 3Cr-lMo-0.25V Steel by Electromagnetic Methods
Nam, Young-Hyun ; Ahn, Bong-Young ; Lee, Seung-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 255~261
DOI : 10.3795/KSME-A.2003.27.2.255
It is advantageous to use NDE methods to assess the mechanical properties of materials since the conventional method is time-consuming and sometimes requires cutting of sample from the component. The NDE parameters such as ultrasonic velocity and attenuation, electric resistivity, and magnetic coercive force and remanance have been utilized to evaluate changes of material properties due to heat treatment condition. It has been found that changes of materials properties under quenched and tempered/PWHT treatments could not be detected using EMAT and Electrical resistivity methods. However, victors hardness and magnetic hysteresis loop decreased with heat treatment procedures. These results were obtained using 3Cr-lMo-0.25V steel. The magnetic parameters were found to be most sensitive to changes of material properties.
Error Estimation for the Semi-Analytic Design Sensitivity Using the Geometric Series Expansion Method
Dan, Ho-Jin ; Lee, Byung-Chai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 262~267
DOI : 10.3795/KSME-A.2003.27.2.262
Error of the geometric series expansion method for the structural sensitivity analysis is estimated. Although the semi-analytic method has several advantages, accuracy of the method prevents it from practical application. One of the promising remedies is the use of geometric series formula for the matrix inversion. Its result of the sensitivity analysis converges that of the global difference method which is known as reliable one. To reduce computational efforts and to obtain reliable results, it is important to know how many terms need to expand. In this paper, the error formula is presented and Its usefulness is illustrated through numerical experiments.
Mathematical Proof for Structural Optimization with Equivalent Static Loads Transformed from Dynamic Loads
Park, Gyung-Jin ; Kang, Byung-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 268~275
DOI : 10.3795/KSME-A.2003.27.2.268
Generally, structural optimization is carried out based on external static loads. All forces have dynamic characteristics in the real world. Mathematical optimization with dynamic loads is extremely difficult in a large-scale problem due to the behaviors in the time domain. The dynamic loads are often transformed into static loads by dynamic factors, design codes, and etc. Therefore, the optimization results can give inaccurate solutions. Recently, a systematic transformation has been proposed as an engineering algorithm. Equivalent static loads are made to generate the same displacement field as the one from dynamic loads at each time step of dynamic analysis. Thus, many load cases are used as the multiple leading conditions which are not costly to include in modern structural optimization. In this research, it is mathematically proved that the solution of the algorithm satisfies the Karush-Kuhn-Tucker necessary condition. At first, the solution of the new algorithm is mathematically obtained. Using the termination criteria, it is proved that the solution satisfies the Karush-Kuhn-Tucker necessary condition of the original dynamic response optimization problem. The application of the algorithm is discussed.
Study on Robustness of Incomplete Cholesky Factorization using Preconditioning for Conjugate Gradient Method
Ko, Jin-Hwan ; Lee, Byung-Chai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 276~284
DOI : 10.3795/KSME-A.2003.27.2.276
The preconditioned conjugate gradient method is an efficient iterative solution scheme for large size finite element problems. As preconditioning method, we choose an incomplete Cholesky factorization which has efficiency and easiness in implementation in this paper. The incomplete Cholesky factorization mettled sometimes leads to breakdown of the computational procedure that means pivots in the matrix become minus during factorization. So, it is inevitable that a reduction process fur stabilizing and this process will guarantee robustness of the algorithm at the cost of a little computation. Recently incomplete factorization that enhances robustness through increasing diagonal dominancy instead of reduction process has been developed. This method has better efficiency for the problem that has rotational degree of freedom but is sensitive to parameters and the breakdown can be occurred occasionally. Therefore, this paper presents new method that guarantees robustness for this method. Numerical experiment shows that the present method guarantees robustness without further efficiency loss.
A Genetic Algorithm based an Optimal Design Methodology for a Lever Sub-Assembly of an Auto Lever
Jung, Hyun-Hyo ; Seo, Kwang-Kyu ; Park, Ji-Hyung ; Lee, Soo-Hong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 285~293
DOI : 10.3795/KSME-A.2003.27.2.285
This paper explores an optimal design methodology for an auto lever using a genetic algorithm. Components of the auto lever have been designed sequentially in the industry, but this study presents a novel design method to determine the design parameters of components simultaneously. The genetic algorithm approach is described to decide a set of design parameters for auto lever. The authors have attempted to model the design problem with the objective of minimizing the angle variation of detent spring subject to constraints such as modulus of elasticity of steel, geometry of shift pipe, and stiffness of spring. This method gives the promising design alternative.
Spectral Element Vibration Analysis of the Pipeline Conveying Internal Flow
Oh, Hyuck-Jin ; Kang, Kwan-Ho ; Lee, U-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 294~301
DOI : 10.3795/KSME-A.2003.27.2.294
It is of often important to accurately predict the flow-induced vibration or dynamic instability of a pipeline conveying internal high speed flow in advance, which requires a very accurate solution method. In this study, first the dynamic equations for the axial and transverse vibrations of a pipeline are reduced from a set of pipe-dynamic equations derived in the previous study and then the spectral element model is formulated. The accuracy of the spectral element method (SEM) is then verified by comparing its results with the results obtained by finite element method (FEM). It is shown that the present spectral element model provides very accurate solutions by using an extremely small number of degrees-of-freedom when compared with FEM. The dynamics of a sample pipeline is investigated with varying the axial tension and the speed of internal flow.
Variational Formulation of Hybrid-Trefftz Plate Elements and Evaluation of Their Static Performance
Choo, Yeon-Seok ; Lee, Byung-Chai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 302~309
DOI : 10.3795/KSME-A.2003.27.2.302
Hybrid-Trefftz plate bending elements are known to be robust and free of shear locking in the thin limit because of Internal displacements fields and linked boundary displacements. Also, their finite element approximation is very simple regardless to boundary shape since all element matrices can be calculated using only boundary integrals. In this study, new hybrid-Trefftz variational formulation based on the total potential energy principle of internal displacements and displacement consistency conditions at the boundary is derived. And flat shell elements are derived by combining hybrid-Trefftz bending stiffness and plane stress stiffness with drilling dofs.
A Development of the Inference Algorithm for Bead Geometry in the GMA Welding Using Neuro-fuzzy Algorithm
Kim, Myun-Hee ; Bae, Joon-Young ; Lee, Sang-Ryong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 310~316
DOI : 10.3795/KSME-A.2003.27.2.310
One of the significant subject in the automatic arc welding is to establish control system of the welding parameters for controlling bead geometry as a criterion to evaluate the quality of arc welding. This paper proposes an inference algorithm for bead geometry in CMA Welding using Neuro-Fuzzy algorithm. The characteristic welding parameters are measured by the circuit composed of hall sensor, voltage divider tachometer, etc. and then the bead geometry of each weld pool is calculated and detected by an image processing with CCD camera and a measuring with microscope. The relationships between the characteristic welding parameters and the bead geometry have been arranged empirically. From the result of experiments, membership functions and fuzzy rules are tuned and determined by the learning of neural network, and then the relationship between actual bead geometry and inferred bead geometry are concluded by fuzzy logic controller. In the applied inference system of bead geometry using Neuro-Fuzzy algorithm, the inference error percent is within -5%∼+4% in case of bead width, -10%∼+10% in bead height, -5%∼+6% in bead area, -10%∼+10% in penetration. Use of the Neuro-Fuzzy algorithm allows the CMA Welding system to evaluate the quality in bead geometry in real time as the welding parameters change.
The Analysis of Fatigue Behavior Using the Delamination Growth Rate(dA
/da) and Fiber Bridging Effect Factor(F
) in Al/GERP Laminates
Song, Sam-Hong ; Kim, Cheol-Woong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 317~326
DOI : 10.3795/KSME-A.2003.27.2.317
The influence of cyclic bending moment on the delamination and the fatigue crack propagation behavior in Al/GFRP laminate such as the wing section was investigated. The main objective of this study was to evaluate the relationship between crack profile and delamination behavior. And a propose parameter on the delamination growth rate(d
/da) of Al/GFRP laminates with a saw-cut using relationship between delamination area(
) and cycles(N), crack length(a), stress intensity factor range(
K). Also, the fiber bridging effect factor(
) was propose that the fiber bridging modification factor(
) to evaluate using the delamination growth rate(d
/da). The shape and size of the delamination zone formed along the fatigue crack between aluminum alloy sheet. Class fiber-adhesive layer were measured by an ultrasonic C-scan image. The shape of delamination zone turns out to be semi-elliptic with the contour decreased non-linearly toward the crack tip. It represents that relationship between crack length and delamination growth rate(d
/da) were interdependent by reciprocal action, therefore it`s applicable present a model for the delamination growth rate(dA/sib D//da) in Al/GFRP laminates.minates.s.
Development of New Back-Up Roll for Strip Shape Control
Lee, Won-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 27, issue 2, 2003, Pages 327~333
DOI : 10.3795/KSME-A.2003.27.2.327
Most of shape defects in steel strip are originated from the structure of rolling mill itself. For instance, strip crown occurs when the work roll is deformed by the bending moment induced on roll chocks. To get rids of the shape defects, it is necessary to increase the stiffness of rolling mill. The structure change of back-up roll is one of alternative ways to increase the mill stiffness without facility revamping from 4 high mill to 6 high mill. In this research work, the new back-up roll was developed and can be used in any type of 4 high mill to reduce the strip shape defects. The developed back-up roll consists of sleeve, arbor and phase angle adjusting system for arbor. The circumference of arbor is specially machined to adapt the strip width change during rolling. The experimental cold rolling test was done to prove the effectiveness of newly developed back-up roll. The experimental rolling results show that the new back-up roll has more powerful performance in reducing the shape defects than conventional back-up roll. It was also found that the new back-up roll has higher stability for shape control. In addition to, the only sleeve surface needs to be reground and changed in most cases, so that the maintenance cost can be greatly reduced.