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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 26, Issue 12 - Dec 2002
Volume 26, Issue 11 - Nov 2002
Volume 26, Issue 10 - Oct 2002
Volume 26, Issue 9 - Sep 2002
Volume 26, Issue 8 - Aug 2002
Volume 26, Issue 7 - Jul 2002
Volume 26, Issue 6 - Jun 2002
Volume 26, Issue 5 - May 2002
Volume 26, Issue 4 - Apr 2002
Volume 26, Issue 3 - Mar 2002
Volume 26, Issue 2 - Feb 2002
Volume 26, Issue 1 - Jan 2002
Selecting the target year
Compensation of the Error due to Hole Eccentricity of Hole-drilling Method in Uniaxile Residual Stress Field Using Neural Network
Kim, Cheol ; Yang, Won-Ho ; Cho, Myoung-Rae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2475~2482
DOI : 10.3795/KSME-A.2002.26.12.2475
The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is compensated using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could compensated the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for compensation of the error due to hole eccentricity in hole-drilling method.
Robust Optimal Design Method Using Two-Point Diagonal Quadratic Approximation and Statistical Constraints
Kwon, Yong-Sam ; Kim, Min-Soo ; Kim, Jong-Rip ; Choi, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2483~2491
DOI : 10.3795/KSME-A.2002.26.12.2483
This study presents an efficient method for robust optimal design. In order to avoid the excessive evaluations of the exact performance functions, two-point diagonal quadratic approximation method is employed for approximating them during optimization process. This approximation method is one of the two point approximation methods. Therefore, the second order sensitivity information of the approximated performance functions are calculated by an analytical method. As a result, this enables one to avoid the expensive evaluations of the exact
derivatives of the performance functions unlike the conventional robust optimal design methods based on the gradient information. Finally, in order to show the numerical performance of the proposed method, one mathematical problem and two mechanical design problems are solved and their results are compared with those of the conventional methods.
Hyperelastic Finite Element Formulation using Pressure Potential
Kim, Heon-Young ; Kim, Ho ; Kim, Joong-Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2492~2502
DOI : 10.3795/KSME-A.2002.26.12.2492
A rubber-like material model is generally characterized by hyperelasticity and formulated by a total stress-total strain relationship because the material shows nonlinear elastic behaviour under large deformation. In this study, a pressure potential obtained by a separately interpolated pressure is introduced to the non-linear finite element formulation incorporating with incompressible or almost incompressible condition of the material. The present formulation is somewhat different from the general formulation using the pressure computed in the displacement field. A non-linear finite element analysis program is developed for the plane strain and the axisymmetric contact problems of a rubber-like material. Various examples with rubber material are analyzed for its verification. The results about deformed shapes and stress distributions thought to be meaningful in comparison with a commercial program, MARC.
Estimation of 3-D Symmetric Shapes Using Shape-from-Shading Technique
Hong, Soon-Hwa ; Hong, Dae-Hie ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2503~2510
DOI : 10.3795/KSME-A.2002.26.12.2503
Since the first shape-form-shading technique was developed by Horn in the early 1970s, many different approaches have been continuously emerging in the past three decades. Some of them improve existing techniques, while others are completely new approaches. Using the image reflectance equation, they estimate the 3-D shape of an object utilizing adequate constraints. Each algorithm applies different constraints such as brightness, smoothness, and integrability to solve the shape-from-shading problem. Especially for symmetric objects, a symmetry constraint is proposed to improve the performance of existing shape-from-shading algorithm in this paper. The symmetry constraint is imposed to a conventional algorithm and then the improvement in the performance of 3-D shape reconstruction is proved by quantitatively comparing the depth and gradient errors.
Dynamic Analysis of an Optical Disk Drive with an Automatic Ball Balancer
Kim, Kang-Sung ; Chung, Jin-Tai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2511~2518
DOI : 10.3795/KSME-A.2002.26.12.2511
Dynamic behaviors and stability of an optical disk drive coupled with an automatic ball balancer (ABB) are analyzed by a theoretical approach. The feeding system is modeled a rigid body with six degree-of-freedom. Using Lagrange`s equation, we derive the nonlinear equations of motion for a non -autonomous system with respect to the rectangular coordinate. To investigate the dynamic stability of the system in the neighborhood of the equilibrium positions, the monodromy matrix technique is applied to the perturbed equations. On the other hand, time responses are computed by the Runge -Kutta method. We also investigate the effects of the damping coefficient and the position of ABB on the dynamic behaviors of the system.
Robust Vehicle Stability Control Using Disturbance Observer
Hahn, Jin-Oh ; Yi, Kyong-Su ; Kang, Soo-Joon ; Lee, Il-Kyo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2519~2526
DOI : 10.3795/KSME-A.2002.26.12.2519
A disturbance observer-based vehicle stability controller is proposed in this paper. The lumped disturbance to the vehicle yaw rate dynamics caused by the uncertain factors such as uncertain tire forces and parameters is estimated by the disturbance observer, which is utilized by the robust controller to stabilize the lateral dynamics of the vehicle. The dynamics of the hydraulic actuator is incorporated in the vehicle stability controller design using the model reduction technique. Modular control design methodology is adopted to effectively deal with the mismatched uncertainty. Simulation results indicate that the proposed disturbance observer-based vehicle stability controller can achieve the desired reference tracking performance as well as sufficient level of robustness.
Optimum Design of Six-Bar Function Generators with Prescribed Functions Defined for the Entire Motion Range
Lee, Sang-Choon ; Shin, Jae-Gyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2527~2534
DOI : 10.3795/KSME-A.2002.26.12.2527
An efficient method is proposed for the design of six-bar function generators with complex design tasks. Especially, the desired functions are defined for the entire motion ranges of the input variables. The design problem is defined as a nonlinear optimization problem. A concept of a weighted structural error is introduced for the definition of the objective function. Also simple branch identifiers are incorporated to eliminate the branch problems commonly encountered in a typical linkage synthesis problem. Two example problems of designing a Watt-II type double dwell mechanism and a Stephenson-III type double beat-up mechanism are demonstrated with numerical results. Constraints such as on the Grashof conditions and on the transmission angles are included for practical solutions.
A Study on Measurement of Micro Weld Deformation by Using PS-ESPI
Lee, Gun-Ha ; Kim, Ji-Tae ; Na, Suck-Joo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2535~2540
DOI : 10.3795/KSME-A.2002.26.12.2535
ESPI is a noncontact, nondestructive and relatively fast inspection method. For these reasons ESPI is being applied as a valuable tool in the nondestructive evaluation of structural components. Phase shifting ESPI is used more effectively than the traditional ESPI because spatial resolution of small object displacements are improved and numerical phase values are obtained for all pixels in the image. Consequently the quantitative measurement of deformation is possible. ESPI fringe patterns are contaminated with high levels of speckle noise. Therefore the phase image is to be smoothed to remove the noise and obtain a better signal-to-noise ratio. In this study, smoothing is done by phase shifting convolution to avoid smoothing errors close to the 2
phase ambiguities in the deformation phase image, and median filter is used as a smoothing filter.
Experimental Modal Analysis of Two Unequal Rectangular Plates Coupled with Fluid
Yoo, Gye-Hyoung ; Jeong, Kyeong-Hoon ; Lee, Seong-Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2541~2549
DOI : 10.3795/KSME-A.2002.26.12.2541
In order to study the vibration characteristics of fluid-structure interaction problem, two rectangular plates coupled with bounded fluid were investigated. Experimental modal analyses were carried out to extract the modal parameters of the system. Additionally. finite element modal analyses performed using a commercial computer code, ANSYS. The FEM solutions were compared with the experimental solutions to verify the finite element model. As a result, the comparison between the experiment and FEM results showed excellent agreement. The transverse vibration modes, in-phase and out-of-phase, were observed alternately in the fluid-coupled system. The thickness effect of the plates on the fluid-coupled natural frequencies and mode shapes was investigated for two different cases with the identical thickness and the unequal thickness. It was found that the coupled natural frequencies increase with the thickness for the identical plates regardless of the mode phase. The experimental and the finite element analysis results showed that the out-of-phase mode shapes were deviated from the symmetrical mode shapes in the plate transverse direction fur the unequal plate thickness case.
A Study on the Processing Characteristic in the Compression Molding of Hybrid Thermoplastic Composites
Heo, Seok-Bong ; Lee, Joong-Hee ; Shin, Gwi-Su ; Rhee, Kyoung-Yop ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2550~2555
DOI : 10.3795/KSME-A.2002.26.12.2550
Hybrid composites usually are defined as composites having different types of reinforcements such as fibers and particles. The major advantage of hybrid composites is able to control the material properties such as optical, electrical, and mechanical properties. For this reason, hybrid composites are widely used in automotive, marine, household, and electrical industries. The objective of this work was to investigate processing characteristics in the compression molding of hybrid thermoplastic composites. The mechanical properties of composites manufactured in various forming conditions were monitored. The composites contained randomly oriented long carbon fiber and carbon black in polypropylene(PP) matrix were used. The carbon fiber contents of composites were 5%, 10%, 15%, and 20%, and carbon black contents were 5%, 10%, 15%, 20%, and 25% by weight. Compression molding was conducted at various mold temperatures. Crstallinity was also measured by using X-RD. The tensile modulus of the composites increased with increasing the mold temperature. However, the impact strength of the composites decreased as the mold temperature increased.
Optimization of Transonic Airfoil Using GA Based on Neural Network and Multiple Regression Model
Kim, Yun-Sik ; Kim, Jong-Hun ; Lee, Jong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2556~2564
DOI : 10.3795/KSME-A.2002.26.12.2556
The design of airfoil had practiced by repeat tests in its first stage, though an airfoil has as been designed based on simulations according to techniques of computational fluid dynamics. Here, using of traditional optimization is unsuitable because a state of flux is hypersensitive to the shape of airfoil. Therefore the paper optimized the shape of airfoil in transonic region using a genetic algorithm (GA). Response surfaces are based on back propagation neural network (BPN) and regression model. Training data of BPN and regression model were obtained by computational fluid dynamic analysis using CFD-ACE, and each analysis has been designed by design of experiments
A Study on Stress Analysis of Small Punch-Creep Test and Its Experimental Correlations with Uniaxial-Creep Test
Lee, Song-In ; Baek, Seoung-Se ; Kwon, Il-Hyun ; Yu, Hyo-Sun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2565~2573
DOI : 10.3795/KSME-A.2002.26.12.2565
A basic research was performed to ensure the usefulness of Small Punch-creep(SP-creep) test for residual life evaluation of heat resistant components effectively. This paper presents analytical results of initial stress and strain distributions in SP specimen caused by constant loading for SP-creep test and its experimental correlations with uniaxial creep(Ten-creep) test on 9Cr1MoVNb steel. It was shown that the initial maximum equivalent stress,
from FE analysis was correlated with steady-state equivalent creep strain rate,
, activation energy, Q and Larson-Miller Parameter, LMP during SP-creep deformation. The simple correlation laws,
adopted to established a quantitative correlation between SP-creep and Ten-creep test data. Especially, the activation energy obtained from SP-creep test is linearly related to that from Ten-creep test at
as follows :
Experimental Verification of the Structural Damage Identification Method Developed for Beam Structures
Cho, Kook-Lae ; Shin, Jin-Ho ; Lee, U-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2574~2580
DOI : 10.3795/KSME-A.2002.26.12.2574
In this paper, an experimental verification has been conducted for the frequency response function (FRF)-based structural damage identification method (SDIM) proposed for beam structures. The FRF-based SDIM requires the natural frequencies and mode shapes measured in the intact state and the FRF-data measured in the damaged state. Experiments are conducted for the cantilevered beam specimens with one slot and with three slots. It is shown that the proposed FRF-based SDIM provides damage identification results that agree quite well with true damage state.
Observation of Tribologically Transformed Structures and fretting Wear Characteristics of Nuclear Fuel Cladding
Kim, Kyeong-Ho ; Lee, Min-Ku ; Rhee, Chang-Kyu ; Wey, Myeong-Yong ; Kim, Whung-Whoe ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2581~2589
DOI : 10.3795/KSME-A.2002.26.12.2581
In this research, fretting tests were conducted in air to investigate the wear characteristics of fuel cladding materials with the fretting parameters such as normal load, slip amplitude, frequency and the number of cycles. A high frequency fretting wear tester was designed for this experiment by KAERI. After the experiments, the wear volume and the shape of wear contour were measured by the surface roughness tester. Tribologically transformed structures(TTS) were analysed by means of optical and scanning electron microscopes to identify the main wear mechanisms. The results of this study showed that the wear volume were increased with increasing slip amplitude, and the shape of wear contour was transformed V-type to W-type. Also, it was found that the critical slip amplitude was 168
. These phenomena mean that wear mechanism transformed partial slip to gross slip to accelerate wear volume. The wear depth increased with an increase of friction coefficient due to increase of normal load and frequency. The fretting wear mechanisms were believed that, after adhesion and surface plastic deformation occurred by relative sliding motion on the contact between two specimens, TTS creation was induced by surface strain hardening and wear debris were detached from the contact surface which were produced by the micro crack propagation and creation.
Output Characteristics and Sensitivity Analysis of Capacitive Type Torque Sensor
Lee, Shin-Pyo ; Kim, Jong-Bo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2590~2597
DOI : 10.3795/KSME-A.2002.26.12.2590
A new torque measuring apparatus adopting the basic principle of a capacitive type sensor is proposed in this article. Two plate electrodes are working as a capacitive sensor, whose capacitance varies as torque is applied. One end of each plate is connected to the torque carrying shaft. Output characteristics of the torque sensor were theoretically analyzed and its validity was investigated through experiment. Calculations and calibration experiments show that the output is nonlinear, that is, the sensitivity is very high at low torque but decreases as torque increases. The sensitivity of the proposed system is about 100 times roughly higher than that of a conventional 4-strain gauge type torque sensor.
Locomotion Mechanism Using a Combination Cam with Multi-Phases
Kim, Kyung-Dae ; Jeong, Youn-Koo ; Kim, Byung-Kyu ; Park, Jong-Oh ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2598~2604
DOI : 10.3795/KSME-A.2002.26.12.2598
Robots that can move along the narrow and rough tube are very important as the request for the inspection increases. It is necessary for the inspection robots to have a capability to move successfully at even overturned situation and have a simple mechanism to reduce the unexpected failure possibility fer the successful completion of the given mission. Through this paper, the authors propose a novel and simple mechanism using a combination cam device to generate the locomotive motion of multi-legs. This robot uses one DC motor and one combination cam shaft to generate the locomotive motion and can move rough tubes without failure even at the overturned situation. The robot also shows enough fragging force fer the connected line that is very important for a wired inspection robot. Kinematics analysis to design the specification of the robot will be followed and several applications show this robot`s potential capabilities.
The Characteristic Analysis of an Automotive Starter Motor with Pole Core
Bae, Joon-Young ; Kim, Jin-Goo ; Lee, Sang-Ryong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2605~2614
DOI : 10.3795/KSME-A.2002.26.12.2605
This paper describes an analysis method based on the experimental parameter for the 0.9kW starter motor of vehicle with permanent magnet and pole core, and analyzed the influence by the effect of pole core of starting motor by using the 2D-FEM analysis technique to reflect the structural characteristic of 3D. A starter motor consists mainly of armature, yoke and permanent magnet with the pole core. Additionally, there is different the axial length of each part. Therefore, the effective of analysis method is needed to improve the characteristic of it. This paper approached the 2D-FEM analysis estimated by the 3D-EMCN(Three Dimensional Equivalent Magnetic Circuit Network) instead of the 3D-FEM analysis to minimize parameters. As a result, this paper is proposed the validity of 2D-FEM analysis and obtained reasonable results for improving a performance.
A Study on 3 Shaft Hydromechanical Transmission Design Considering Power and Speed Characteristics
Sung, Duk-Hwan ; Kim, Hyun-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2615~2623
DOI : 10.3795/KSME-A.2002.26.12.2615
In this paper, a systematic design approach for a three shaft hydromechanical transmission(HMT) system is proposed by considering the power characteristics and speed ratio range. Using network analysis, possible configurations of the 3 shaft HMT are analyzed and it is found that the influence of HSU stroke on the power distribution of the HMT can be investigated by the network analysis. In addition, design methods are presented from the viewpoint of (1) power distribution and (2) speed ratio range. From the power distribution and the speed ratio range, a HMT configuration can be constructed, which minimizes the power circulation and provides the desired speed ranges. Based on the 3 shaft HMT analyses and the proposed design approach, a 3 shaft HMT is designed which provides 4 speeds in forward and 1 speed in reverse while keeping the power circulation less than 150% of the input power. It is expected that the design method suggested in this study can be used in a systematic design of the 3 shaft HMT.
A study on the Synthesis and Characterization of Polyimide/TiO
Lee, Bong-Shin ; Lee, Joong-Hee ; Kim, In-Taek ; Lee, Myong-Hoon ; Nah, Chang-Woon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2624~2630
DOI : 10.3795/KSME-A.2002.26.12.2624
Organic/inorganic hybrid materials have rapidly become a fascinating research field. In this study,
composites were synthesized from nano-sized anatase
and two types of polyimide, that is, BPDA-PPD and PMDA-ODA. Nano-sized
particles were prepared from
solution by the sol-gel method. The synthesized PI/
composites were characterized by using XRD, TGA, FT-IR, TEM, and Atomic Force Microscope(AFM).
particles were dispersed well in polyimides and the mechanical and thermal stability of polyimide was improved with
The Semi-Analytic Structural Sensitivity Using Pade Approximation
Dan, Ho-Jin ; Lee, Byung-Chai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2631~2635
DOI : 10.3795/KSME-A.2002.26.12.2631
The semi-analytic sensitivity analysis using Pade approximation is presented for linear elastic structures. Although the semi-analytic method has several advantages, accuracy of the method prevents it from practical application. One of promising remedies is the use of geometric series for the matrix inversion. Though series expansion of order three has been successfully applied to the calculation of the structural sensitivity in the most range of the design perturbation, it is prone to have a slow convergence for large perturbation. To overcome this shortage, Pade approximation is introduced so that it can broaden the trust region of the perturbation without adding expansion terms. Numerical results show that the confident sensitivity can be obtained with tiny expenses of computation effort.
Dynamic Analysis of a Rotating System Due to the Effect of Ball Bearing Waviness (I)-Vibration Analysis-
Jeong, Seong-Weon ; Jang, Gun-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2636~2646
DOI : 10.3795/KSME-A.2002.26.12.2636
This research presents an analytical model to investigate vibration due to ball bearing waviness in a rotating system supported by two or more ball bearings, taking account of the centrifugal force and gyroscopic moment of the ball. The waviness of rolling elements is modeled by the sinusoidal function, and it is incorporated into the position vectors of the race curvature center. The Hertzian con tact theory is applied to calculate the elastic deflection and nonlinear contact force while the rotor has translational and angular motions. Both the centrifugal force and gyroscopic moment of the ball and the waviness of the rolling elements are included in the kinematic constraints and force equilibrium equations of a ball to derive the nonlinear governing equations of the rotor, which are solved by using the Runge-Kutta-Fehlberg algorithm to determine the new position of the rotor. The proposed model is validated by the comparison of the results of the prior researchers. This research shows that the centrifugal force and gyroscopic moment of the ball plays the important role in determining the bearing frequencies, i.e. the principal frequencies, their harmonics and the sideband frequencies resulting from the waviness of the rolling elements of ball bearing. It also shows that the bearing vibration frequencies are generated by the waviness interaction not only between the rolling elements of one ball bearing but also between those of two or more ball bearings constrained by the rotor.
Dynamic Analysis of a Rotating System Due to the Effect of Ball Bearing Waviness (I) -Vibration Analysis-
Jeong, Seong-Weon ; Jang, Gun-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2647~2655
DOI : 10.3795/KSME-A.2002.26.12.2647
This research presents an analytical model to investigate the stability due to the ball bearing waviness i n a rotating system supported by two ball bearings. The stiffness of a ball bearing changes periodically due to the waviness in the rolling elements as the rotor rotates, and it can be calculated by differentiating the nonlinear contact forces. The linearized equations of motion can be represented as a parametrically excited system in the form of Mathieu`s equation, because the stiffness coefficients have time -varying components due to the waviness. Their solution can be assumed as a Fourier series expansion so that the equations of motion can be rewritten as the simultaneous algebraic equations with respect to the Fourier coefficients. Then, stability can be determined by solving the Hill`s infinite determinant of these algebraic equations. The validity of this research is proved by comparing the stability chart with the time responses of the vibration model suggested by prior researches. This research shows that the waviness in the rolling elements of a ball bearing generates the time-varying component of the stiffness coefficient, whose frequency is called the frequency of the parametric excitation. It also shows that the instability takes place from the positions in which the ratio of the natural frequency to the frequency of the parametric excitation corresponds to i/2 (i
Finite Element Analysis of Shot Peening Effected by Multiple Impacts
Kim, Tae-Joon ; Kim, Nak-Soo ; Park, Soon-Cheol ; Jeong, Won-Wook ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2656~2661
DOI : 10.3795/KSME-A.2002.26.12.2656
Multiple impact models to examine the effect of stress interference are proposed and investigated. The single shot model analysis, which used various shot ball conditions, was carried out to compare with multiple impacts analysis. Then the multiple impact analysis were performed to predict the effect of the shot ball distances. The results showed that the stress interference in the multiple impact model significantly reduced the maximum value of the compressive residual stresses. The residual stress profiles were strongly effected by the shot ball distances. The multiple impact model can simulate a realistic shot peening process rather than a single shot model does. It is concluded that the proposed model predicts the real process more accurately.
Effect of Temperature and Immersion Time on the Environmental Adhesive Strength of Adhesively Bonded Joints of Rolled Steel Sheet
Song, Jun-Hee ; Lee, Hee-Jae ; Lim, Jae-Kyoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2662~2669
DOI : 10.3795/KSME-A.2002.26.12.2662
Recently structural applications of adhesive bonding method have been increased extensively in automobile industry. Adhesively-bonded joints which are used in automobile field are exposed to various environmental conditions. In this study, several environmental factors were concerned to evaluate their effects on the adhesive strength such as air temperature, water temperature, exposed time in water. The specimens are exposed for 1, 10 and 100 hours at various air temperatures to evaluate the effects of the air and water temperature on the adhesive strength. It is proved that the adhesive strength decrease with rising the air and water temperature, and the adhesive strength decrease steeply at the higher temperature with increasing the exposure time in water.
Prediction of Spread and Contact Region in Ring Rolling Process Using Rigid- plastic Finite Element Method
Ko, Young-Soo ; Yoon, Hwan-Jin ; Kim, Nak-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2670~2677
DOI : 10.3795/KSME-A.2002.26.12.2670
The ring rolling process involves three-dimensional non-steady material flow and continuous change of radius and thickness of the ring workpiece. In this study, the deformation analysis and geometric updating algorithm of the ring rolling process were verified by using the three-dimensional rigid-plastic finite element method. Manufacturing processes for plain ring and T-shaped ring were investigated by comparing experiments with simulation results, especially in side spread, load-stroke and pressure distribution, showing a good agreement. It was concluded that the simulation method would be a useful tool for the design of a ring rolling process.
Use of the Delayed Time Fuzzy Controller for Autonomous Wheelchairs
Ryu, Yeong-Soon ; Ga, Chun-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2678~2686
DOI : 10.3795/KSME-A.2002.26.12.2678
A novel approach is developed for avoidance of obstacles in unknown environment. This paper proposes a new way of intelligent autonomous wheelchairs for the handicapped to move safely and comfortably. It is the objective of this paper to develop delayed time fuzzy control algorithms to deal with various obstacles. This new algorithm gives the benefit of the collision free movement in real time and optimal path to the moving target. The computer simulations and the experiments are demonstrated to the effect of the suggested control method.
A Measuring Method for 3-DOF Displacement by Using Spherical Reflector
Kwon, Ki-Hwan ; Moon, Hong-Kie ; Cho, Nahm-Gyoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2687~2694
DOI : 10.3795/KSME-A.2002.26.12.2687
A precision displacement measuring system is proposed, which can detect the 3-DOF translational motions of precision positioning devices. The optical system, which is composed of two diode-laser sources and two quadratic PSDs, is adapted to detect the position of the spherical reflector usually mounted on the platform of positioning devices. Each of the laser beams from diode-laser sources is reflected at the highly reflective surface of the sphere; hence, the 3-dimensional position of the sphere causes the directional change of the reflected beams, which is detected by the PSDs. In this paper, we define the relationships between the output values of the two PSDs and the 3-DOF translational motions of the sphere. Based on a deduced measurement model, we perform measurement simulation and evaluate the performance of the proposed measurement system: linearity, sensitivity, measuring range, and measurement error. The results show that the proposed measuring method is very useful for the measurement of the precision displacement of 3-DOF micro motions.
Transmission Error Analysis of the Helical Gears for the Elevator
Park, Chan-Il ; Kim, Dae-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2695~2702
DOI : 10.3795/KSME-A.2002.26.12.2695
The elevator gear box with the helical gears needs to be developed instead of the one with the worm gears to improve the efficiency. In order to develop the gear box, the analytical tool to predict the helical gear noise is necessary to meet customer`s noise requirement. Gear noise is related to the loaded transmission error. Therefore, the simulation program fer the loaded transmission error analysis of the helical gears is developed in this study. Using the developed program, the effects of tooth modification such as tip relief and the extent of tip relief are investigated. Finally, the procedures to determine the tip relief and the extent of tip relief are proposed.
Energy Absorption Characteristics and Optimal Welding Space of Square Hat Type Thin-walled Tube
Lee, Hyung-Yil ; Kim, Bum-Joon ; Han, Byoung-Kee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 26, issue 12, 2002, Pages 2703~2714
DOI : 10.3795/KSME-A.2002.26.12.2703
In this work, energy absorption characteristics and optimal welding space of spot-welded square hat type tube are investigated via quasi-static crush experiments and finite element (FE) analyses. A FE model reflecting the crush characteristics is established based on the experimentally observed crush mechanisms of specimens with welding spaces (20, 30 & 45 mm) and (25,40 & 55 mm) respectively for two specimen widths (60, 75 mm). The established FE model is then applied to other crush models of widths (50, 60 & 75 mm) with various welding spaces (20, 25, 30, 40, 45, 55, 75, 150, 300 mm) respectively. We examine the energy absorption characteristics with respect to the welding space for each specimen width. The outcome suggests an optimal spot welding space of square hat type thin-walled tube. Energy absorption is also presented in terms of yield strength of base metal, specimen thickness, width, and mean crushing force of spot-welded square hat type thin-walled tube.