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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 29, Issue 12 - Dec 2005
Volume 29, Issue 11 - Nov 2005
Volume 29, Issue 10 - Oct 2005
Volume 29, Issue 9 - Sep 2005
Volume 29, Issue 8 - Aug 2005
Volume 29, Issue 7 - Jul 2005
Volume 29, Issue 6 - Jun 2005
Volume 29, Issue 5 - May 2005
Volume 29, Issue 4 - Apr 2005
Volume 29, Issue 3 - Mar 2005
Volume 29, Issue 2 - Feb 2005
Volume 29, Issue 1 - Jan 2005
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An Evaluation of Low Intensity Ultrasonic Characteristics for Arthritis Healing
Hong Sung-Min ; Han Seung-Moo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 787~794
DOI : 10.3795/KSME-A.2005.29.6.787
Nowadays chronic degenerative diseases such as arthritis are increasing rapidly, even though acute infectious diseases are decreasing due to the advance of modern medicine. Although many of remedies are developed for arthritis healing, there is no precise medical prescription, and pathogenesis is not examined exactly. In this study, we confirmed gene expression of BMP 1A, BMP 2B, osteonectin and MGP which are genes related with bone formation in osteoblast by using ultrasonic stimulation. Through this study, we also evaluated the fact that ultrasound could be applied to arthritis healing by making activated osteoblast induce remodeling of cartilage. As a result of this research, BMP 2B and MGP have higher rates of expression in specific ultrasound mode. In conclusion, it is expected that ultrasound could be used efficiently for healing arthritis if we use ultrasounds according to symptoms of arthritis on reasonable terms.
Study on the Observability of a Calibration System for a Parallel Tilting Table with Measuerment Operator
Park Kun Woo ; Lee Min Ki ; Kim Tae Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 795~803
DOI : 10.3795/KSME-A.2005.29.6.795
This paper studies the observability of calibration system with a measurement operator. The calibration system needs a simple digital indicator to measure the mobile table movements with respect to the MC coordinate. However, it yields the concern about the poor parameter observability due to measuring only a part of the movements. We uses the QR-decomposition to find the optimal calibration configurations maximizing the linear independence of rows of an observation matrix. The number of identifiable parameter is examined by the rank of the observation matrix, which represents the parameter observability. The method is applied to a 6-axis MC with parallel tilting table and the calibration results are presented. These results verify that all necessary kinematic parameters are observable and the calibration system has robustness to the noise using optimal calibration configurations.
Correlation Study on Tire Belt Adhesion Properties and Durability Performance
Hong Seungjun ; Lee Hoguen ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 804~808
DOI : 10.3795/KSME-A.2005.29.6.804
A pneumatic tire is made up of many flexible filaments of high modulus cord of natural textile, synthetic polymer, glass fiber, or fine hard drawn steel embedded in and bonded to a matrix of low modulus polymetric material. Adhesion property of these materials is very important in tire durability safety because belt-leaving-belt tread separation reduces the ability of a driver to control a vehicle, whether or not the separation is accompanied by a loss of air. In this study adhesion test of carcass-belt-tread is conducted on material properties of 5 PCR tire model, which are on sale in domestic market and analyzed adhesion properties. For those tire models FMVSS 109 indoor high speed durability test is conducted to analyze the correlation between adhesion force and high speed performance of tires and found the correlation between the two test results.
Optimization of T-Structure Supporting Steering System Using μGA
Lee Jong Soo ; Kim Sung Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 809~814
DOI : 10.3795/KSME-A.2005.29.6.809
The goal of this paper is to minimize the weight of the T-structure supporting steering system in reducing the vibration level on steering wheel which could be amplified by the resonance. Presently, requirements for reducing noise, vibration and harshness (NVH) in automotive area are more stringent than ever. One of them is the vibration of steering system which occurs sometimes at high speeds or when the engine is idling. Besides, the reduction of weight is also one of requirements for improvement of vehicle performance. This paper used the micro genetic algorithm as an optimization method to satisfy above two requirements. The whole T-structure assembly including steering column was used for frequency analysis.
A Proposal of Parameter to Predict Biaxial Fatigue Life for CF8M Cast Stainless Steels
Park Joong Cheul ; Kwon Jae Do ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 815~821
DOI : 10.3795/KSME-A.2005.29.6.815
Biaxial low cycle fatigue test was carried out to predict fatigue life under combined axial-torsional-loading condition which is that of in-phase and out-of-phase for CF8M cast stainless steels. Fatemi-Socie(FS) parameter which is based on critical plane approach is not only one of methods but also the best method that can predict fatigue life under biaxial loading condition. But the result showed that, biaxial fatigue life prediction by using FS parameter with several different parameters for the CF8M cast stainless steels is not conservative but best results. So in this present research, we proposed new fatigue life prediction parameter considering effective shear stress instead of FS parameter which considers the maximum normal stress acting on maximum shear strain and its effectiveness was verified.
Influence of Stress Ratio of Elastic Waves Generated by Fatigue Crack Growth and Penetration in 6061 Aluminum Plates
Ahn Seok Hwan ; Kim Jin Wook ; Nam Ki Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 822~827
DOI : 10.3795/KSME-A.2005.29.6.822
The characteristics of elastic waves emanating from crack initiation and propagation in 6061 aluminum alloy subjected to fatigue loading with different stress ratio was investigated. The objective of this study is to determine the properties of the signals generated from each stage of fatigue crack growth. AS a crack propagates, substantial elastic wave occurred just prior to penetration. Then it decreased and the crack penetrated. The waveforms and their power spectra were found to be dependent on the different stress ratio associated with the signals. It is determined that high-frequency signal
MHz is most likely emitted during crack propagation at peak load of fatigue cycle which release the highest energy. It is determined that 0.3 MHz is closely related to crack closure effect. The frequency peaks below 0.25 MHz may be attributed to fretting or hydraulic noise.
A Study on the Birefringence Measurement in Injection Molded Parts Using R-G-B Separation of White Light
Yoon Kyunghwan ; Kim Jongsun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 828~834
DOI : 10.3795/KSME-A.2005.29.6.828
Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in optical plastic parts using R-G-B separation of white light. The main idea of an analysis comes from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. A complete system to give the quantitative values of retardation covering high order 2-D birefringence will be demonstrated. Further investigation is under way to improve the accuracy of the system using diodes as light sources.
A Study on Optimal Design of Rocker Arm Shaft Using Improved Genetic Algorithm
Lee Soo Jin ; An Yong Su ; Lee Dong Woo ; Cho Seok Swoo ; Joo Won Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 835~841
DOI : 10.3795/KSME-A.2005.29.6.835
This study proposes a new optimization algorithm which is combined with genetic algorithm and ANOM. This improved genetic algorithm is not only faster than the simple genetic algorithm, but also gives a more accurate solution. The optimizing ability and convergence rate of a new optimization algorithm is identified by using a evaluation function which have several local optimum and an optimum design of rocker arm shaft. The calculation results are compared with the simple genetic algorithm.
Sequential Approximate Optimization Based on a Pure Quadratic Response Surface Method with Noise Filtering
Lee Yongbin ; Lee Ho-Jun ; Kim Min-Soo ; Choi Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 842~851
DOI : 10.3795/KSME-A.2005.29.6.842
In this paper, a new method for constrained optimization of noisy functions is proposed. In approximate optimization using response surface methods, if constraints have severe noise, the approximate feasible region defined by approximate constraints is apt to include some of the infeasible region defined by actual constraints. This can cause the approximate optimum to converge into the infeasible region. In the proposed method, the approximate optimization is performed with the approximate constraints shifted by their deviations, which are calculated using a diagonal quadratic response surface method. This can prevent the approximate optimum from converging into the infeasible region. To fit the objective and constraints into diagonal quadratic models, we select the center and 4 additional points along each axis of design variables as experimental points. The deviation of each function is calculated using the differences between the real and approximate function values at the experimental points. A sequential approximate optimization technique based on the trust region algorithm is adopted to manage approximate models. The proposed approach is validated by solving some design problems. The results of the problems show the effectiveness of the proposed method.
Molecular Dynamics Simulation of Deformation of Polymer Resist in Nanoimpirnt Lithography
Kim Kwang-Seop ; Kim Kyung-Woong ; Kang Ji-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 852~859
DOI : 10.3795/KSME-A.2005.29.6.852
Molecular dynamics simulations of nanoimprint lithography in which a stamp with patterns is pressed onto amorphous poly-(methylmethacrylate) (PMMA) surface are performed to study the deformation of polymer. Force fields including bond, angle, torsion, inversion, van der Waals and electrostatic potential are used to describe the intermolecular and intramolecular force of PMMA molecules and stamp. Periodic boundary condition is used in horizontal direction and Nose-Hoover thermostat is used to control the system temperature. As the simulation results, the adhesion forces between stamp and polymer are calculated and the mechanism of deformation are investigated. The effects of the adhesion and friction forces on the polymer deformation are also studied to analyze the pattern transfer in nanoimprint lithography. The mechanism of polymer deformation is investigated by means of inspecting the indentation process, molecular configurational properties, and molecular configurational energies.
The Meshfree Method Based on the Least-Squares Formulation for Elasto-Plasticity
Youn Sung-Kie ; Kwon Kie-Chan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 860~875
DOI : 10.3795/KSME-A.2005.29.6.860
A new meshfree method for the analysis of elasto-plastic deformations is presented. The method is based on the proposed first-order least-squares formulation, to which the moving least-squares approximation is applied. The least-squares formulation for the classical elasto-plasticity and its extension to an incrementally objective formulation for finite deformations are proposed. In the formulation, the equilibrium equation and flow rule are enforced in least-squares sense, while the hardening law and loading/unloading condition are enforced exactly at each integration point. The closest point projection method for the integration of rate-form constitutive equation is inherently involved in the formulation, and thus the radial-return mapping algorithm is not performed explicitly. Also the penalty schemes for the enforcement of the boundary and frictional contact conditions are devised. The main benefit of the proposed method is that any structure of cells is not used during the whole process of analysis. Through some numerical examples of metal forming processes, the validity and effectiveness of the method are presented.
Evaluation on Tensile Properties and Fracture Toughness of Glass Fiber/Aluminum Hybrid Laminates
Woo Sung-Choong ; Choi Nak-Sam ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 876~888
DOI : 10.3795/KSME-A.2005.29.6.876
Tensile properties and fracture toughness of monolithic aluminum, fiber reinforced plastics and glass fiber/aluminum hybrid laminates under tensile loads have been investigated using plain coupon and single-edge-notched specimens. Elastic modulus and ultimate tensile strength of GFMLs showed different characteristic behaviors according to the Al kind, fiber orientation and composition ratio. Fracture, toughness of A-GFML-UD which was determined by the evaluation of
based on critical load was similar to that of GFRP-UD and was much higher than monolithic Al. Therefore, A-GFML-UD presented superior fracture toughness as well as prominent damage tolerance in comparison to its constituent Al. By separating Al sheet from GFMLs after the test, optical microscope observation of fracture zone of GFRP layer in the vicinity of crack tip revealed that crack advance of GFMLs depended on the orientation of fiber layer as well as Al/fiber composition ratio.
Modal Analysis Employing In-plane Strain of Cantilever Plates Undergoing Translational Acceleration
Yoo Hong Hee ; Lim Hong Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 889~894
DOI : 10.3795/KSME-A.2005.29.6.889
A modeling method for the modal analysis of cantilever plates undergoing in-plane translational acceleration is presented in this paper. Cartesian deformation variables are employed to derive the equations of motion and the resulting equations are transformed into dimensionless forms. To obtain the modal equation from the equations of motion, the in-plane equilibrium strain measures are substituted into the strain energy expression based on Von Karman strain measures. The effects of two dimensionless parameters (related to acceleration and aspect ratio) on the modal characteristics of accelerated plates are investigated through numerical studies.
Uniform Scallop Height Tool Path Generation Using CL Surface Deformation
Yang Min-Yang ; Kim Su-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 895~903
DOI : 10.3795/KSME-A.2005.29.6.895
In this paper, we present a cutter location (CL) surface deformation approach for constant scallop height tool path generation from triangular mesh. The triangular mesh model of the stereo lithography (STL) format is offset to the CL surface and then deformed in accordance with the deformation vectors, which are computed by the slope and the curvature of the CL surface. In addition, the tool path which is computed by slicing the deformed CL surface is inversely deformed by those same deformation vectors to a tool path with a constant scallop height. The proposed method is implemented, and a tool path generated by the proposed method is tested by simulation and by numerical control (NC) machining. The scallop height was found to be constant over the entire machined surface, demonstrating much better quality than that of mesh slicing, under the same constraints for machining time.
Development of a Three-Dimensional Barrier Embedded Kenics Micromixer by Means of a Micro-Stereolithography Technology
Lee In Hwan ; Kwon Tai Hun ; Cho Dong-Woo ; Kim Dong Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 904~912
DOI : 10.3795/KSME-A.2005.29.6.904
The flow in a microchannel is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved. In this regard, we developed a novel chaotic micromixer, named Barrier Embedded Kenics Micromixer (BEKM). In the BEKM, the higher level of chaotic mixing can be achieved by combining two general chaotic mixing mechanisms: (i) splitting/reorientation by helical elements inside the microchannel and (ii) stretching/folding via periodically located barriers on the channel wall. The fully three-dimensional geometry of BEKM was realized by a micro-stereolithography technology, in this study, along with a Kenics micromixer and a circular T-pipe. Mixing performances of three micromixers were experimentally characterized in terms of an average mixing color intensity of phenolphthalein. Experimental results show that BEKM has better mixing performance than other two micromixers. Chaotic mixing mechanism, proposed in this study, could be integrated as a mixing component with Micro-Total-Analysis-System, Lab-on-a-chip and so on.
Development of a Finite Element Human Neck Model for Neck Injury Analysis - Application to Low Speed Rear-End Offset Impacts -
Kim Young Eun ; Jo Hui Chang ;
Transactions of the Korean Society of Mechanical Engineers A, volume 29, issue 6, 2005, Pages 913~920
DOI : 10.3795/KSME-A.2005.29.6.913
Compared to previous in-vitro test, FE model showed reliable motion patterns. A finite element model of a 50th percentile male neck was developed to study the mechanics of whiplash injury while the rear impacts. The model was consisted of the whole cervical vertebrae including part of occipital, intervertebral discs. which were modeled using linear viscoelastic materials and posterior elements. The sliding interfaces were defined to simulate contact phenomena in facet joints and in odontoid process. All ligaments and atlanto-occipital membrane were modeled as nonlinear bar elements. Only muscle elements were not considered. Motion of each cervical vertebra was obtained from the dynamic simulation with a MADYMO model for 15 km/h
rear end offset impacts. Soft tissue neck injury(STNI) was investigated with a developed FE model. In FE model analysis, the high stress was appeared at C3/C4 disc in offset impact. Further research is still needed in order to improve the developed neck FE model for many different crash patterns.