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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
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 35, Issue 12 - Dec 2011
Volume 35, Issue 11 - Nov 2011
Volume 35, Issue 10 - Oct 2011
Volume 35, Issue 9 - Sep 2011
Volume 35, Issue 8 - Aug 2011
Volume 35, Issue 7 - Jul 2011
Volume 35, Issue 6 - Jun 2011
Volume 35, Issue 5 - May 2011
Volume 35, Issue 4 - Apr 2011
Volume 35, Issue 3 - Mar 2011
Volume 35, Issue 2 - Feb 2011
Volume 35, Issue 1 - Jan 2011
Selecting the target year
Reliability-Based Design Optimization Using Enhanced Pearson System
Kim, Tae-Kyun ; Lee, Tae-Hee ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 125~130
DOI : 10.3795/KSME-A.2011.35.2.125
Since conventional optimization that is classified as a deterministic method does not consider the uncertainty involved in a modeling or manufacturing process, an optimum design is often determined to be on the boundaries of the feasible region of constraints. Reliability-based design optimization is a method for obtaining a solution by minimizing the objective function while satisfying the reliability constraints. This method includes an optimization process and a reliability analysis that facilitates the quantization of the uncertainties related to design variables. Moment-based reliability analysis is a method for calculating the reliability of a system on the basis of statistical moments. In general, on the basis of these statistical moments, the Pearson system estimates seven types of distributions and determines the reliability of the system. However, it is technically difficult to practically consider the Pearson Type IV distribution. In this study, we propose an enhanced Pearson Type IV distribution based on a kriging model and validate the accuracy of the enhanced Pearson Type IV distribution by comparing it with a Monte Carlo simulation. Finally, reliability-based design optimization is performed for a system with type IV distribution by using the proposed method.
A Multicellular Spheroid Formation and Extraction Chip Using Removable Cell Trapping Barriers
Jin, Hye-Jin ; Kim, Tae-Yoon ; Cho, Young-Ho ; Gu, Jin-Mo ; Kim, Jhin-Gook ; Oh, Yong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 131~134
DOI : 10.3795/KSME-A.2011.35.2.131
We propose a spheroid chip that uses removable cell trapping barriers and that is capable of forming and extracting multicellular spheroids. By using a conventional well plate and flask, it is difficult to form small-sized spheroids, which resemble avascular 3D cell-cell interaction. It was difficult to extract spheroids using conventional microchips and fixed cell trapping barriers. The proposed chip, however, facilitates both formation and extraction of spheroids by using removable cell trapping barriers formed by membrane deflection. The cell trapping barriers, formed at the membrane pressure of 50 kPa, hold the cells in the trapping region at a cell inlet pressure of 145.155 Pa. After incubation for 24 h, the trapped cells form uniform spheroids. We successfully extract the spheroids at a cell inlet pressure of 5 kPa after removing the membrane pressure. The extracted spheroids have a diameter of
with a viability of
. Using the proposed chip, uniform spheroids can be formed and these spheroids can be safely extracted for carrying out the post-processing of spheroids.
System for Real-Time Analysis of Body Posture of Home Inhabitant by Using a Tilt Sensor
Cha, Joo-Heon ; Jun, Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 135~141
DOI : 10.3795/KSME-A.2011.35.2.135
A smart home provides services that its inhabitant needs or wants, by integrating and simultaneously controlling various devices and sensors. In this study, we focused on a smart-home system for people with disabilities and for elderly people. We introduced a new type of system for real-time analysis of body posture of the inhabitants of a smart home. The system includes the concept that offers remote healthcare or medical services by using a 3D tilt sensor for recognizing the static and dynamic postures of inhabitants in real time. It consists of a smart-home server and a 3D tilt sensor, and it uses wireless technology to communicate with the inhabitants and thus enhance their mobility. The smart-home server includes the inference engine that differentiates the dynamic postures from the static ones. Finally, we also demonstrate the usefulness of the proposed system by applying it to a real environment.
Development of a Forecasting Model for Refinery Crude Column Overhead Corrosion Control
Kim, Seung-Nam ; Kim, Jung-Hwan ; Moon, Il ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 143~148
DOI : 10.3795/KSME-A.2011.35.2.143
Corrosion at the top of a distillation column is a common problem in refineries and chemical plants. In particular, severe damage has been inflicted in refineries by corrosive materials such as hydrogen sulfide and chlorine. Therefore, the mechanism of the corrosion occurring at the top of a distillation column has been analyzed, and a model for forecasting the corrosion rate has been developed. Four major materials were selected for modeling:
. These were selected by taking into consideration their effect on the corrosion rate. Studies on the transport phenomenon and reaction engineering for this model were carried out, and the reliability of the model was verified on the basis of the data measured at a real refinery.
Acquisition of Data of Equipments on Shop Floor Using Interface Between Various Equipments
Nam, So-Jeong ; Lee, Jai-Kyung ; Lee, Sung-Woo ; Park, Jong-Kweon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 149~156
DOI : 10.3795/KSME-A.2011.35.2.149
There is much information of equipment in shop floor because the manufacturing processes are different as the equipment within the manufacturing process is varied. To provide effective process information to MES and other production systems, the DAS requires an equipment monitoring system that takes into account the characteristics of the equipment on the shop floor. In this study, we proposed some methods for collecting the required information about various equipments on a shop floor. The equipments such as CNC can be interfaced with the DAS by using a PLC-based method and a sensor-based interface board can be used to interface general equipments. The proposed methods can be used to collect information on the shop floor in real-time. Moreover these methods are very adaptive and can be easily modified according to the changes made to the shop floor. The information about a real shop floor acquired by employing these methods is saved in a database and the can be provided to a supervisor and MES so that they are aware of the status of the shop floor.
Creep-Fatigue Life Design with Various Stress and Temperature Conditions on the Basis of Lethargy Coefficient
Park, Jung-Eun ; Yang, Sung-Mo ; Han, Jae-Hee ; Yu, Hyo-Sun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 157~162
DOI : 10.3795/KSME-A.2011.35.2.157
High temperature and stress are encounted in power plants and vehicle engines. Therefore, determination of the creep-fatigue life of a material is necessary prior to fabricating equipments. In this study, life design was determined on the basis of the lethargy coefficient for different temperatures, stress and rupture times. SP-Creep test data was compared with computed data. The SP-Creep test was performed to obtain the rupture time for X20CrMoV121 steel. The integration life equation was considered for three cases with various load, temperature and load-temperature. First, the lethargy coefficient was calculated by using the obtained rupture stress and the rupture time that were determined by carrying out the SP-Creep test. Next, life was predicted on the basis of the temperature condition. Finally, it was observed that life decreases considerably due to the coupling effect that results when fatigue and creep occur simultaneously.
Study on Feasibility of Applying Function Approximation Moment Method to Achieve Reliability-Based Design Optimization
Huh, Jae-Sung ; Kwak, Byung-Man ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 163~168
DOI : 10.3795/KSME-A.2011.35.2.163
Robust optimization or reliability-based design optimization are some of the methodologies that are employed to take into account the uncertainties of a system at the design stage. For applying such methodologies to solve industrial problems, accurate and efficient methods for estimating statistical moments and failure probability are required, and further, the results of sensitivity analysis, which is needed for searching direction during the optimization process, should also be accurate. The aim of this study is to employ the function approximation moment method into the sensitivity analysis formulation, which is expressed as an integral form, to verify the accuracy of the sensitivity results, and to solve a typical problem of reliability-based design optimization. These results are compared with those of other moment methods, and the feasibility of the function approximation moment method is verified. The sensitivity analysis formula with integral form is the efficient formulation for evaluating sensitivity because any additional function calculation is not needed provided the failure probability or statistical moments are calculated.
Time-Based Characteristics of Acoustic Emission During Dental Composite Restoration
Gu, Ja-Uk ; Choi, Nak-Sam ; Arakawa, Kazuo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 169~174
DOI : 10.3795/KSME-A.2011.35.2.169
Acoustic emission (AE) signals were detected and analyzed in real time during the polymerization shrinkage of composite resin restoration in an artificial dental ring with a class I cavity. Most AE hit events were observed in the initial curing period of the 1st region with high contraction rate. The range of the
region for the stainless steel specimen was shorter than that for the PMMA specimen but longer than that for the human dentin specimen. AE hit events showed a blast-type signal having an amplitude in the range of 25.45 dB and a frequency band of 100.200 kHz or 240.300 kHz. These values of amplitude and frequency indicated the fracture of resin or of the adhesive layer.
A Noise-Robust Measuring Algorithm for Small Tubes Based on an Iterative Statistical Method
Kim, Hyoung-Seok ; Naranbaatar, Erdenesuren ; Lee, Byung-Ryong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 175~181
DOI : 10.3795/KSME-A.2011.35.2.175
We propose a novel algorithm for measuring the radius of tubes. This proposed algorithm is capable of effectively removing added noise and measuring the radius of tubes within allowable precision. The noise is removed by using a candidate true center that minimizes the standard deviation with respect to the radius. Further, the disconnection in data points resulting from noise removal is solved by using a connection algorithm. The final step of the process is repeated until the value of the standard deviation decreases to a small predefined value. Experiments were performed using circle geometries with added noise and a real tube with complex noise and that is used in the braking units of automobiles. It was concluded that the measurement carried out using the algorithm was accurate within 1.4%, even with 15% added noise.
Design Optimization of a Heat Sink for Mobile Telecommunication Module Satisfying Temperature Limits
Jeong, Seung-Hyun ; Jeong, Hyun-Su ; Lee, Yong-Bin ; Choi, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 183~190
DOI : 10.3795/KSME-A.2011.35.2.183
As the number of mobile subscribers has increased recently, the demand for more number of base stations has increased. However, because of the shortage of sites for constructing base stations, a mobile communication module needs to be small in size. To minimize the size of the module, the size of the heat sink attached to the outside of the module should be minimized. Furthermore, the temperature of each electronic component of the module should be lower than the allowable temperature so that thermal stability can be maintained. A commercial PIDO (process integration and design optimization) tool PIAnO and a commercial CFD (computational fluid dynamics) tool FLOTHERM are used to minimize the size of the module while the constraints on the temperatures of the twelve electronic components are satisfied. As a result of design optimization, the volume of the heat sink is reduced by 41.9% while all the constraints on the temperature of the twelve electronic components of the module are satisfied.
High-temperature Structural Analysis of Small-scale Prototype of Process Heat Exchanger (III)
Song, Kee-Nam ; Lee, Heong-Yeon ; Kim, Chan-Soo ; Hong, Seong-Duk ; Park, Hong-Yoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 191~200
DOI : 10.3795/KSME-A.2011.35.2.191
A PHE (Process Heat Exchanger) is a key component of nuclear hydrogen system for massive production of hydrogen; the PHE transfers the very high temperature heat (
) generated from the VHTR (Very High Temperature Reactor) to a chemical reaction. The Korea Atomic Energy Research Institute developed a small-scale gas loop for testing the performance of VHTR components and manufactured a modified PHE prototype for carrying out the testing in the gas loop. In this study, as a part of the evaluation of the high-temperature structural integrity of the modified PHE prototype which is scheduled to test in the gas loop, we carried out high-temperature structural analysis modeling, macroscopic thermal and structural analysis of the PHE prototype under the gas loop test conditions as a precedent study before carrying out the performance test in the gas loop. The results obtained in this study will be used to design the performance test setup for the modified PHE prototype.
Study on Characteristics of Sliding Support for Fuel Rod
Song, Kee-Nam ; Lee, Sang-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 201~206
DOI : 10.3795/KSME-A.2011.35.2.201
A spacer grid assembly is one of the most important structural components of the nuclear fuel assembly of a pressurized water reactor (PWR), and it affects the performance of the fuel assembly. The primary design requirement is that the mechanical integrity of the fuel rod should be maintained by the spacer grid assembly during the operation of the reactor. It was known that fretting damage to the fuel rod can be reduced by adjusting the relative moving displacement between the fuel rod and its support. In this study, we used the finite element method to evaluate the characteristics of a sliding support designed to reduce fretting damage of fuel rods.
Optimal Design for Minimizing Weight of Housing of Hydraulic Breaker
Park, Gyu-Byung ; Park, Chang-Hyun ; Park, Yong-Shik ; Choi, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 207~212
DOI : 10.3795/KSME-A.2011.35.2.207
A hydraulic breaker is an attachment installed at the end of excavator arm and is used for breaking. As per the authors' knowledge, there have been no research results on reducing the weight of the hydraulic breaker even though this weight reduction is very important for improving the performance of the excavator. In this study, we minimize the weight of the housing of the hydraulic breaker under normal operating conditions, while the maximum stress of the housing is lower than the allowable stress. A meta-model, which is generated by using the CAE results for the sampling design points determined by an orthogonal array, is used to solve the minimization problem. The weight of the housing according to the optimal design is found to be lower than the original weight by 4.8% while satisfying the constraint on the maximum stress.
Weight Reducing of Aluminum Extrusion Profiles of a Railway-Car Body Based on Topology and Size Optimization
Han, Soon-Woo ; Jung, Hyun-Seung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 2, 2011, Pages 213~221
DOI : 10.3795/KSME-A.2011.35.2.213
In this study, we discussed the weight reducing of a urban railway-car body, in particular, of the Korean EMU, by optimizing topology and size of aluminum extrusion profiles. The heaviest parts of aluminum railway-car bodies, i.e., the base plate of underframe and side panels of side frame composed of double skin structures are considered for optimization. Topology optimization process is applied to obtain get an optimized rib structure for the base plate. The thickness of ribs and plates of the topologically optimized base plate and the existing side panel are also optimized by employing the size optimization process. The results are verified by comparing the maximum von Mises stresses and maximum deformation in the case of the existing design with those in the case of the optimized design. It is shown that the weight of a base plate and side panel can be reduced by 12% and that the weight of the whole car body can be reduced by 8.5%.