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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 33, Issue 12 - Dec 2009
Volume 33, Issue 11 - Nov 2009
Volume 33, Issue 10 - Oct 2009
Volume 33, Issue 9 - Sep 2009
Volume 33, Issue 8 - Aug 2009
Volume 33, Issue 7 - Jul 2009
Volume 33, Issue 6 - Jun 2009
Volume 33, Issue 5 - May 2009
Volume 33, Issue 4 - Apr 2009
Volume 33, Issue 3 - Mar 2009
Volume 33, Issue 2 - Feb 2009
Volume 33, Issue 1 - Jan 2009
Selecting the target year
Numerical Fracture Mechanics Evaluation on Surface Cracks in a Spherical Oxygen Holder
Cho, Doo-Ho ; Kim, Jong-Min ; Chang, Yoon-Suk ; Choi, Jae-Boong ; Kim, Young-Jin ; Han, Sang-In ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1187~1194
DOI : 10.3795/KSME-A.2009.33.11.1187
During the last decade, possibility of flaw occurrences has been rapidly increased world-widely as the increase of operating times of petro-chemical facilities. For instance, from a recent in-service inspection, three different sized surface cracks were detected in welding parts of a spherical oxygen holder in Korea. While API579 code provides corresponding engineering assessment procedures to determine crack driving forces, in the present work, numerical analyses are carried out for the cracked oxygen holder to investigate effects of complex geometry, analysis model and residual stress. With regard to the detailed finite element analysis, stress intensity factors are determined from both the full three-dimensional model and equivalent plate model. Also, as an alternative, stress intensity factors are calculated for equivalent plate model by employing the noted influence stress function technique. Finally, parametric structural integrity evaluation of the cracked oxygen holder is conducted in use of failure assessment diagram method, J/T method and DPFAD method. Effects of the geometry and so forth are examined and key findings from the simulations are fully discussed, which enables to determine practical safety margins of spherical components containing a defect.
Reliability Estimation and RBDO Using Kriging Metamodel and Genetic Algorithm
Cho, Tae-Min ; Lee, Byung-Chai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1195~1201
DOI : 10.3795/KSME-A.2009.33.11.1195
In this study, effective methods for reliability estimation and reliability-based design optimization(RBDO) are proposed using kriging metamodel and genetic algorithm. In our previous study, we proposed the accurate method for reliability estimation using two-staged kriging metamodel and genetic algorithm. In this study, the possibility of applying the previously proposed method to RBDO is investigated. The efficiency and accuracy of that method were much improved than those of the first order reliability method(FORM). Finally, the effective method for RBDO is proposed and applied to numerical examples. The results are compared to the existing RBDO methods and shown to be very effective and accurate.
Biomechanical Characterization with Inverse FE Model Parameter Estimation: Macro and Micro Applications
Ahn, Bum-Mo ; Kim, Yeong-Jin ; Shin, Jennifer H. ; Kim, Jung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1202~1208
DOI : 10.3795/KSME-A.2009.33.11.1202
An inverse finite element (FE) model parameter estimation algorithm can be used to characterize mechanical properties of biological tissues. Using this algorithm, we can consider the influence of material nonlinearity, contact mechanics, complex boundary conditions, and geometrical constraints in the modeling. In this study, biomechanical experiments on macro and micro samples are conducted and characterized with the developed algorithm. Macro scale experiments were performed to measure the force response of porcine livers against mechanical loadings using one-dimensional indentation device. The force response of the human liver cancer cells was also measured by the atomic force microscope (AFM). The mechanical behavior of porcine livers (macro) and human liver cancer cells (micro) were characterized with the algorithm via hyperelastic and linear viscoelastic models. The developed models are suitable for computing accurate reaction force on tools and deformation of biomechanical tissues.
Replication of Polyethylene Nano-Microstructures Using Ultrasonic Forming
Lee, Chi-Hoon ; Yu, Hyun-Woo ; Shin, Bo-Sung ; Ko, Jong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1209~1216
DOI : 10.3795/KSME-A.2009.33.11.1209
Nano-micro hierarchical structures that nanoprotrusions were formed on the network-type microstructures were fabricated using an ultrasonic vibration forming technology. A commercial ultrasonic welding system was used to apply ultrasonic vibration energy. To evaluate the formability of ultrasonic vibration forming, nickel nano-micro hierarchical mold was fabricated and polyethylene (PE) was used as the replication material. The optimal molding time was 3.5 sec for PE nano-micro hierarchical structures. The molding process was conducted at atmospheric pressure.
Torsional Rigidity of a Two-stage Cycloid Drive
Kim, Kyoung-Hong ; Lee, Chun-Se ; Ahn, Hyeong-Joon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1217~1224
DOI : 10.3795/KSME-A.2009.33.11.1217
This paper presents a finite element (FE) analysis of the torsional rigidity of a two-stage cycloid drive. The cycloid disk makes contact with a number of pin-rollers simultaneously and eccentric shafts transmit not only torque of the spur gear stage to the cycloid disk, but also that of the cycloid disk to the output disk. Contacts between the disk and pin-rollers are simplified as linear spring elements, and the bearing of eccentric shaft is modeled as a rigid ring that has frictional contact to the disk and an elastic support. FE analysis for an ideal solid cycloid drive was performed and verified by a theoretical calculation. Accurate contact forces were then estimated by iterating between FE analysis for contact forces and Hertz theory calculations for nonlinear contact stiffness. In addition, torsional rigidity of the cycloid drive is analyzed to show that the bearing and nonlinear Hertz contact theory should be considered in analysis and design of a cycloid drive, which was verified with experiments. Finally, the effects of contact stiffness, bearing stiffness and cycloid disk structural stiffness according to the cycloid disk rotation on the torsional rigidity were investigated.
Structural Optimization of a Control Arm with Consideration of Durability Criteria
Kim, Jong-Kyu ; Park, Young-Chul ; Kim, Young-Jun ; Lee, Kwon-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1225~1232
DOI : 10.3795/KSME-A.2009.33.11.1225
This study suggests a structural design process for the upper control arm installed at a vehicle. Static strength and durability are the most important responses in the structural design of a control arm. This study considers the static strength in the optimization process. The inertia relief method for FE analysis is utilized to simulate the static loading conditions. According to the classification of structural optimization, the structural design of a control arm is included in the category of shape optimization. In this study, the metamodel technique using the kriging method is adopted to obtain the minimum weight satisfying the strength constraint. Then, the final design is suggested by considering the durability criteria. The durability assessment is obtained by the index of fatigue durability called the SWT (Smith-Watson-Topper) index. The final optimum shape has been proposed by trial and error method.
Characterization of High Temperature Strength of Si
Composite Ceramics According to the Amount of SiO
Nano Colloidal Added
Nam, Ki-Woo ; Lee, Kun-Chan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1233~1238
DOI : 10.3795/KSME-A.2009.33.11.1233
This study analyzed the characterization of high temperature strength of
composite ceramics additive based on variations in the amount of nano colloidal
added. Semi-elliptical cracks about 100
length were obtained from a Vickers indenter using a load of 24.5 N. The results showed that the heat-treated smooth specimens with
nano colloidal coating exhibited the highest bending strength at 0.0 wt%
nano colloidal added, which is amounted to a 187 % increase over that of smooth specimen. Limiting temperature for bending strength of crack-healed zone for bending strength was about 1273 K. However, the bending strength of SSTS-3 and SSTS-4 was considerably increased while that of SSTS-1 and SSTS-2 was decreased at a temperature of 1,573K.
Seismic Analysis of the Cooling Water Pump for Nuclear Power Plant for the Seismic Load
Chung, Chul-Sup ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1239~1243
DOI : 10.3795/KSME-A.2009.33.11.1239
To evaluate the structural integrity of the nuclear seismic category penetration cooling water pump under the seismic service conditions the seismic analysis was performed in accordance with IEEE-STD-344 code. The finite element computer program, ANSYS, Version 10.0, is used to perform both a mode frequency analysis and an equivalent static seismic analysis of the pump assembly. The mode frequency analysis results show the fundamental natural frequency is greater than 33 Hz and does not exist in seismic range, thus justifying the use of the static analysis. The stresses resulted from various loadings and their combinations are within the allowable limits specified in the above mentioned IEEE code. The results of the seismic evaluation fully satisfied the structural acceptance criteria of the IEEE code. Accordingly the structural integrity on the pump assembly was proved.
Estimation of Dynamic Stiffness of a Rubber Bush
Goo, Jun-Hwan ; Ahn, Tae-Kil ; Kim, Joo-Sung ; Lee, Yong-Heon ; Bae, Dae-Sung ; Kim, Kee-Joo ; Choi, Byung-Ik ; Lee, Hak-Joo ; Woo, Chang-Su ; Kim, Kyung-Shik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1244~1248
DOI : 10.3795/KSME-A.2009.33.11.1244
Although rubber components are extensively used in mechanic parts. There are still a lot of difficulties in designing the rubber components applied in complex shapes and preloaded states because of the complicated material properties. One of the most important parameters for more detailed and accurate mechanical analysis during the development stages is the dynamic characteristics of the rubber components. It is well known that the dynamic properties of rubber are dependent on frequency as well as static preload. Consequently, a large number of experiments have to be conducted to identify the dynamic stiffness of a rubber bush considering the various applied conditions. In this paper, an efficient experimental method is suggested, which estimates the dynamic stiffness of a rubber bush using rubber material test and static stiffness of the bush. This method is capable of predicting the dynamic stiffness of a rubber bush under various load conditions from minimized test data.
Effect of Interface in Three-phase Cord-Rubber Composites
Kim, Jong-Kuk ; Yum, Young-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1249~1255
DOI : 10.3795/KSME-A.2009.33.11.1249
Cord-rubber composites widely used in tires show very complicated mechanical behavior such as nonlinearity and large deformation. Three-phase(cord, rubber and the interface) modeling has been used to analyze the stress distribution in the cord-rubber composites more accurately. In this study, finite element methods were performed using two-dimensional generalized plane strain element and plane strain element to investigate the stress distribution and effective modulus of cord-rubber composites. Neo Hookean model was used for rubber property and several interface properties were assumed for various loading directions. It was found that the interface properties affect the effective modulus and the distributions of shear stress.
A Study on Characteristics of Plasma Emission Signals with Welding Conditions in CO
Kim, Jong-Do ; Lee, Chang-Je ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1256~1261
DOI : 10.3795/KSME-A.2009.33.11.1256
Today, implementation of the defect detection in laser welding has been researched for a long time, but most studies have been made around thin plate within
. Therefore, this study was measured and analyzed light emission signals of the induced plasma in
laser lap welding of
Zn primer-coated steel, and based on this analysis, research made an investigation into possibility of monitoring in thick plate welding. It was been analyzing the measured signals by RMS and FFT processing, as a results, we were able to confirm definite difference of two signals between humping bead and sound bead. Thus, possibility of real time monitoring in
laser lap welding verified experimentally.
Noise and Vibration Analysis for Net Form Slabs
Kim, Young-Woo ; Kang, Ki-Jun ; Jung, Jun-Oh ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1262~1266
DOI : 10.3795/KSME-A.2009.33.11.1262
The slab(flat) truss plate used for building construction is analyzed for vibration and noise. Using floor impact test and numerical method (FEM), both net form and traditional form are compared for vibration and noise. The results show that the frequencies of a net form are lower than those of a traditional form in the case of free vibration, and the noise values of a net form are lower than those of a traditional form for the range from 500 Hz to 2000 Hz.
Evaluation of Design Parameters for Optimizing the Cooling Channel in Hot Press Bending Process
Nam, Ki-Ju ; Choi, Hong-Seok ; Ko, Dae-Cheol ; Kim, Byung-Min ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1267~1273
DOI : 10.3795/KSME-A.2009.33.11.1267
Hot press forming can produce high-strength components by rapidly cooling between closed punch and die after hot forming using quenchable boron steel austenized in a furnace. In the hot press forming process, the cooling rate is influenced by the size, position and arrangement of the cooling channel and the file condition of cooling water in the die. Also, mechanical properties of the final components and operation time are related to cooling rate. Therefore, the design of optimized cooling channel is one of the most important works. In this paper, the effect of position and size of the cooling channel on the cooling rate was investigated by using design of experiment and FE analysis in hot press bending process. Therefore the optimum cooling channel ratio was presented in the HPB.
A Study on Fracture Characteristic of Ceramic Dome Using Shock Tube
Hwang, Kwon-Tae ; Kim, Jae-Hoon ; Lee, Young-Shin ; Park, Jong-Ho ; Kwon, Sun-Guk ; Song, Kee-Hyuck ; Yoon, Su-Jin ; Lee, Gi-Chun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1274~1278
DOI : 10.3795/KSME-A.2009.33.11.1274
Fracture characteristics for plate and dome shapes of glass filled ceramics using shock tube were carried out. Glass filled ceramics have been considered as a promising candidate material for the dome port cover of air breathing engine. This part of the air breathing engine has an important role as separated membrane between combustion and external air, and needs the frangible characteristics that the particles of fractured glass filled ceramics should not affect the internal components of combustion. The objectives of this study are to evaluate the fracture pressures for various thicknesses and diameters of shock impact area. Also fracture phenomena of separated membrane using a shock tube compare with analytical method. The experimental apparatus consists of a driver, a driven section and a dump tank. The used material is glass filled ceramic made from Corning company. Specimens have the thickness of 3, 4.5 and 6mm. It is expected that the results obtained from this study can be used in the basic data for the dome port cover design of an air breathing engine.
A Study About Weld Defects Detection By Using A Magnetostrictive Sensor
Na, Hyun-Ho ; Kim, Ill-Soo ; Seo, Joo-Hwan ; Son, Sung-Woo ; Jeong, Jae-Won ; Kim, Ji-Sun ; Lee, Ji-Hye ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1279~1287
DOI : 10.3795/KSME-A.2009.33.11.1279
An increasingly competitive business environment has been concentrated on industries to reduce the operating costs. Industries such as gas, oil, petrochemical, chemical, and electric power have employed for the operation and used for large equipment or structures that require a high capital investment. In order to meet these requirements, the industries are increasingly moving toward saving the experimental verification and computer simulation. Therefore industries to reduce the maintenance costs without compromising the operational safety have been forced on finding for better and more efficient methods to inspect their equipment and structures. In this study, it focused on the development the real-time non-contract monitoring system as an efficient tool for the experimental study of weld defects based on the relationship between the measured voltage and input parameters.
Response Characteristics of Two Block System under Seismic Base Excitation
Shin, Tae-myung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1288~1293
DOI : 10.3795/KSME-A.2009.33.11.1288
This paper discusses about modeling method to simulate a nonlinear behavior like sliding or rocking of two stacked body system under earthquake condition. A double body system design can be an option to reduce seismic response of a component in comparison to a single body system for free standing structures. Therefore, according to the priority of components, the structure is to be designed by proper ratio of partition in their height for improvement of seismic capability and structural integrity. Nonlinear modeling and analysis using simple rigid body and dynamic system has been performed to check the trend in such cases. As a result, one of the two bodies can be chosen to reduce the seismic response from energy absorption of the other one by appropriate application of friction ratios not only in slip-slip condition but in slip-rock condition.
Real-time Simulation for Dynamic Characteristics of Mechanical Braking of the Korean Tilting Train
Kim, Ho-Yeon ; Kang, Chul-Goo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1294~1299
DOI : 10.3795/KSME-A.2009.33.11.1294
The Korean tilting train called Hanvit 200 was launched recently in Korea to improve train speed up to 200 km/h at conventional lines. In this paper, we propose a HILS system for simulations of mechanical braking of the Hanvit 200 train using actual ASCU, actual dump valves, Simulink, dSPACE board, and ControlDesk software. In the proposed HILS system, dynamics of wheelsets, bogies and car body, brake force generation, creep force generations are realized via mathematical models, and anti-skid logic is realized using actual components. The validity of the proposed HILS system is demonstrated via comparing results of real-time and off-line simulations.
Swimming Microrobot Actuated by External Magnetic Field
Byun, Dong-Hak ; Kim, Jun-Young ; Baek, Seung-Man ; Choi, Hyun-Chul ; Park, Jong-Oh ; Park, Suk-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1300~1305
DOI : 10.3795/KSME-A.2009.33.11.1300
The various electromagnetic based actuation(EMA) methods have been proposed for actuating microrobot. The advantage of EMA is that it can provide wireless driving to microrobot. In this reason a lot of researchers have been focusing on the EMA driven microrobot. This paper proposed a swimming microrobot driven by external alternating magnet field which is generated by two pairs of Helmholtz coils. The microrobot has a fish-like shape and consists of a buoyant robot body, a permanent magnet, and a fin. The fin is directly linked to the permanent magnet and the magnet is swung by the alternating magnet field, which makes the propulsion and steering power of the robot. In this paper, firstly, we designed the locomotive mechanism of the microrobot boy EMA. Secondly, we set up the control system. Finally, we demonstrated the swimming robot and evaluated the performance of the microrobot by the experiments.
Dynamic Analysis of a Three-dimensional Catenary System Using the Finite Element Method
Lee, Kyo-Ho ; Cho, Yong-Hyun ; Chung, Jin-Tai ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1306~1313
DOI : 10.3795/KSME-A.2009.33.11.1306
Dynamic and static behaviors of a three-dimensional catenary system for a high-speed railway are analyzed by using the finite element method. Considering tensions in the contact wire and the messenger wire, we drive the equations of motion for the catenary system. These equations are for the longitudinal, transverse, vertical and torsional motions. After establishing the weak form, the weak forms are spatially discretized with newly defined two-node beam elements. With the discretized equations, a finite element computer program is developed for the static and dynamic analyses. The static deflections of the catenary system, which are important for good contact between the pantograph and the contact line, are computed when the gravity is applied. On the other hand, we analyze the natural frequencies and the corresponding natural modes of the catenary system. The dynamic responses of the system are also investigated when applying a load to the contact line. For verification of the developed finite element program, vibrations of the catenary system are measured and they are compared to computed time responses.
Statistical Estimation of Modal Characteristics of a Structural System Based on Design Variable Samples
Kim, Yong-Woo ; Yoo, Hong-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1314~1319
DOI : 10.3795/KSME-A.2009.33.11.1314
The design methods of mechanical systems are largely classified into deterministic methods and stochastic methods. In deterministic methods, design parameters are assumed to have fixed values. On the other hand, in stochastic methods, design parameters are assumed to be statistically distributed. When a stochastic method is employed, statistical characteristics of the populations of design variables are assumed to be known. However, very often, it is almost impossible or very expensive to obtain the statistical characteristics of the populations. Therefore a sample survey method is usually employed for stochastic methods. This paper describes the procedure of estimating the statistical characteristics of populations by employing sample data sets. An example of AFM micro cantilever beam is employed to show the effectiveness of the procedure.
Vibration Transmission of Railway Floor Structure due to Connecting Materials
Shin, Bum-Sik ; Chun, Kwang-Wook ; Choi, Yeon-Sun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1320~1325
DOI : 10.3795/KSME-A.2009.33.11.1320
The sources of the vibration of railway vehicles in the cabin are usually bogie, axle, and wheel. The vibrations are transmitted through the floor structures of railway vehicle. The floor structure is the combination of bottom plate, plywood, and rubber. In this research the vibration transmission is measured experimentally and analyzed numerically to find the transmission characteristics of the vehicle floor structures. The result shows that the vibration characteristic of soft rubber is better than hard rubber or wood as the connecting material between the bottom plate and the plywood.
Virtual Sensor Verification Using Neural Network Theory of the Quadruped Robot
Ko, Kwang-Jin ; Kim, Wan-Soo ; Yu, Seung-Nam ; Han, Chang-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1326~1331
DOI : 10.3795/KSME-A.2009.33.11.1326
The sensor data measured by the legged robot are used to recognize the physical environment or information that controls the robot`s posture. Therefore, a robot`s ambulation can be advanced with the use of such sensing information. For the precise control of a robot, highly accurate sensor data are required, but most sensors are expensive and are exposed to excessive load operation in the field. The seriousness of these problems will be seen if the prototype`s practicality and mass productivity, which are closely related to the unit cost of production and maintenance, will be considered. In this paper, the use of a virtual sensor technology was suggested to address the aforementioned problems, and various ways of applying the theory to a walking robot obtained through training with an actual sensor, and of various hardware information, were presented. Finally, the possibility of the replacement of the ground reaction force sensor of legged robot was verified.
A Study on the Bucket Loading Characteristics for Wheel-loader Loading Automation
Seo, Dong-Kwan ; Seo, Hyun-Jae ; Kang, In-Pil ; Kwon, Young-Min ; Lee, Sang-Hoon ; Hwang, Sung-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1332~1340
DOI : 10.3795/KSME-A.2009.33.11.1332
The front end wheel loader is widely used for the loading of materials in mining and construction fields. It has repetitive digging, loading and dumping procedures. The bucket is subjected to large resistance force from the soil during scooping. We considered the soil reaction force characteristics from scooping procedure, the protection by overload and automatic scooping mode algorithm. The main topic of this paper is the analysis of the soil reaction force characteristics. The analysis of soil mechanics is carried out and the developed soil model is verified by experimental results from the simplified experimental equipment. A simplified model of the soil shape and bucket trajectory is used to determine the scooping direction based on an estimation of the resistance force applied on the bucket during the scooping motion. In the future, this model will be used for the generation of an appropriate path for the wheel loader automation.
Application of the Durability Reinforcement Technique on the Frame Structure
Kwon, Sung-Hun ; Yoo, Hong-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1341~1346
DOI : 10.3795/KSME-A.2009.33.11.1341
In this paper, the technique to reinforce the durability performance of structure using the sensitivity information for the frame structure is applied. The fatigue life calculation for the frame structure is performed from the quasi-static and transient analysis and the characteristics of two methods are compared for the fatigue analysis. Then the reinforcement technique is applied. First, some design variables related to the locations of fatigue failure is selected. Then sensitivities of fatigue life at fracture points with respect to the variation of design variables are calculated and the vector composed of gaps between the target life and initial life cycles is calculated. If the number of fatigue fracture points is same as the number of design variables, the variations of the design variables are calculated from the linear algebraic equation. If not, the variations of the design variables are calculated from the optimization formulation with the constraints.
Development of the Six Degree-of-Freedom Active Vibration Isolation System by Using a Phase Compensated Velocity Sensor
Kim, Yong-Dae ; Kim, Sang-Yoo ; Park, Kyi-Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1347~1352
DOI : 10.3795/KSME-A.2009.33.11.1347
Magnetic force driven six degree-of-freedom active vibration isolation system is developed. The velocity sensor using an electromagnetic principle that is commonly used in the vibration control is investigated since its phase lead characteristic causes an instability problem for a low frequency vibration. A lag-type compensator is adopted to reduce the phase lead and the stability test is performed by using a Bode analysis. The performance of the AVIS is validated by comparing with the passive isolation system by using the frequency responses.
Characteristic Comparison of Linear Thrust Forces for Magnet Wheels
Shim, Ki-Bon ; Jung, Kwang-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 33, issue 11, 2009, Pages 1353~1356
DOI : 10.3795/KSME-A.2009.33.11.1353
As a method obtaining linear thrust force for the magnet wheel producing a strong traction torque, the concept of magnetic shield is suggested and compared with the existing approaches. Specially, as the magnet wheel, in which the permanent magnets rotate mechanically instead of ac driving to make traveling field, is physically similar with the rotary induction motor, there is a periodical force ripple in tangential direction as well as normal direction. But, the force ripple can be suppressed from a shape change of the shield plate. Namely, the change brings out a change of entry and exit effect of the circumferential field for the magnet wheel. The feasibility of the shield concept is verified from simulation and experiment.