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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 31, Issue 12 - Dec 2007
Volume 31, Issue 11 - Nov 2007
Volume 31, Issue 10 - Oct 2007
Volume 31, Issue 9 - Sep 2007
Volume 31, Issue 8 - Aug 2007
Volume 31, Issue 7 - Jul 2007
Volume 31, Issue 6 - Jun 2007
Volume 31, Issue 5 - May 2007
Volume 31, Issue 4 - Apr 2007
Volume 31, Issue 3 - Mar 2007
Volume 31, Issue 2 - Feb 2007
Volume 31, Issue 1 - Jan 2007
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Performance Test and Finite Element Analysis of Air Spring for Automobile
Huh, Shin ; Woo, Chang-Soo ; Han, Houk-Seop ; Kim, Wan-Doo ; Kim, Seong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 725~731
DOI : 10.3795/KSME-A.2007.31.7.725
An air spring which is a part of the suspension system of automobiles is used to reduce and absorb the vibration and the noise. Main components of the air spring are a cord reinforced rubber bellows, a canister and a piston. The performance of the air spring are depended on configurations of rubber bellows, the angle and elastic modulus of cord. The finite element analysis are executed to predict and evaluate the load capacity and the stiffness. The design variables of air spring are determined to adjust the required specifications of the air spring. Several samples of the air spring are manufactured and experimented. It is shown that the results by finite element analysis are in close agreement with the test results.
Effect of Melt-mixing Conditions on Fracture Properties of Bioabsorbable HA/PLLA Composite Materials
Park, Sang-Dae ; Lee, Deok-Bo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 732~738
DOI : 10.3795/KSME-A.2007.31.7.732
Effects of melt-mixing conditions on fracture properties of hydroxyapatite filled bioabsorbable poly(L-lactic acid)(HA/PLLA) composites was investigated by measuring the firacture toughness value of HA/PLLA composites prepared under different mixing time and rotor speed. The fracture surface morphology was also examined by profile measurement and scanning electron microscopies. It was found that the fracture toughness of HA/PLLA composites decreases due to decrease of ductile deformation of PLLA matrix and debonding of interfaces with increase of the rotor speed and mixing time. Effect of mixing process on neat PLLA was also assessed, and it was found that the fracture toughness of PLLA decreases due to disappearance of multiple craze formation and increase of defects. Such thermal and shear-stress degradation were found to be the primary mechanisms of the degradation of HA/PLLA composites during melt-mixing process.
Generating FE Mesh Automatically from STL File Model
Park, Jung-Min ; Kwon, Ki-Youn ; Lee, Byung-Chai ; Chae, Soo-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 739~746
DOI : 10.3795/KSME-A.2007.31.7.739
Recently, models in STL files are widely used in reverse engineering processes, CAD systems and analysis systems. However the models have poor geometric quality and include only triangles, so the models are not suitable for the finite element analysis. This paper presents a general method that generates finite element mesh from STL file models. Given triangular meshes, the method estimates triangles and makes clusters which consist of triangles. The clusters are merged by some geometric indices. After merging clusters, the method applies plane meshing algorithm, based on domain decomposition method, to each cluster and then the result plane mesh is projected into the original triangular set. Because the algorithm uses general methods to generate plane mesh, we can obtain both tri and quad meshes unlike previous researches. Some mechanical part models are used to show the validity of the proposed method.
A Data Driven Motion Generation for Driving Simulators Using Motion Texture
Cha, Moo-Hyun ; Han, Soon-Hung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 747~755
DOI : 10.3795/KSME-A.2007.31.7.747
To improve the reality of motion simulator, the method of data-driven motion generation has been introduced to simply record and replay the motion of real vehicles. We can achieve high quality of reality from real samples, but it has no interactions between users and simulations. However, in character animation, user controllable motions are generated by the database made up of motion capture signals and appropriate control algorithms. In this study, as a tool for the interactive data-driven driving simulator, we proposed a new motion generation method. We sample the motion data from a real vehicle, transform the data into the appropriate data structure(motion block), and store a series of them into a database. While simulation, our system searches and synthesizes optimal motion blocks from database and generates motion stream reflecting current simulation conditions and parameterized user demands. We demonstrate the value of the proposed method through experiments with the integrated motion platform system.
Damage Evaluation of Wheel Tread for High Speed Train Using Replication and Fracture Mechanics Characteristics
Kwon, Seok-Jin ; Lee, Dong-Hyung ; Seo, Jung-Won ; Kwon, Sung-Tae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 756~763
DOI : 10.3795/KSME-A.2007.31.7.756
The majority of catastrophic wheel failures are caused by surface opening fatigue cracks either in the wheel tread or wheel flange areas. The inclined cracks at railway wheel tread are initiated and the cracks are caused by wheel damage-spatting after 60,000 km running. Because the failured railway wheel is reprofiled before regular wheel reprofiling, the maintenance cost for the railway wheel is increased. Therefore, it is necessary to analyze the mechanism for initiation of crack. In the present paper, the combined effect on railway wheels of a periodically varying contact pressure and an intermittent thermal braking loading is investigated. To analyze damage cause for railway wheels, the measurements for replication of wheel surface and the effect of braking application in field test are carried out. The result shows that the damages in railway wheel tread are due to combination of thermal loading and ratcheting.
Filing Experiments and Structural Analysis of Human Body
Lee, Se-Hoon ; Choi, Young-Jin ; Choi, Eui-Jung ; Chae, Je-Wook ; Lee, Young-Shin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 764~776
DOI : 10.3795/KSME-A.2007.31.7.764
On the human-rifle system, the human body is affected by the firing impact. The firing impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The musculoskeletal model is developed by finite element method using beam and spar elements. In this study structural analysis has been performed in order to investigate the human body impact by firing of 5.56mm small caliber machine gun. The firing experiments with the standing shooting postures were performed to verify analytical results. The result if this study shows analytical displacements of the human-rifle system and experimental displacements of the real firing. As the results, the analytical displacement and stress of human body are presented.
Study of Spring Modeling Techniques for Kinematic and Dynamic Analysis of a Spring Operating Mechanism for the Circuit Breaker
Sohn, Jeong-Hyun ; Lee, Seung-Kyu ; Kim, Seung-Oh ; Yoo, Wan-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 777~783
DOI : 10.3795/KSME-A.2007.31.7.777
Since the performance of the circuit breaker mainly depends on the spring operating mechanism, the analysis of the spring operating mechanism is required. The spring, especially closing spring, stores the deformation energy due to the compression and then accelerates the big loads rapidly in the circuit breaker. To accurately carry out the kinematic and dynamic analysis of the circuit breaker, the precise modeling of the spring behavior is necessary. In this paper, the static stiffness of the spring is captured by using the tester. A simple mechanism similar to the spring operating mechanism was designed to generate the release motion of the spring. A high speed camera was used to capture the behavior of the spring. Three types of spring models such as a linear spring model, modal spring model, and nodal spring model are suggested and compared with the experimental results.
Analysis of Two-Dimensional Fretting Wear Using Substructure Method
Bae, Joon-Woo ; Chai, Young-Suck ; Lee, Choon-Yeol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 784~791
DOI : 10.3795/KSME-A.2007.31.7.784
Fretting, which is a special type of wear, is defined as small amplitude tangential oscillation along the contacting interface between two materials. In nuclear power plants, fretting wear caused by flow induced vibration (FIV) can make a serious problem in a U-tube bundle in steam generator. In this study, substructure method is developed and is verified the feasibility for the finite element model of fretting wear problems. This method is applied to the two-dimensional finite element analyses, which simulate the contact behavior of actual tube to support. For these examples, computing time can be reduced up to 1/5 in comparisons with conventional finite element analyses.
Mechanical Behaviors under Compression in Wire-woven Bulk Kagome Truss PCMs (II) - Effects of Geometric and Material Imperfections -
Hyun, Sang-Il ; Choi, Ji-Eun ; Kang, Ki-Ju ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 792~799
DOI : 10.3795/KSME-A.2007.31.7.792
A newly developed cellular metal based on kagome lattice is an ideal candidate for multifunctional materials achieving various optimal properties. Intensive efforts have been devoted to develop efficient techniques for mass production due to its wide potential applications. Since a variety of imperfections would be inevitably included in the realistic fabrication processes, it is highly important to examine the correlation between the imperfections and material strengths. Previous performance tests were mostly done by numerical simulations such as finite element method (FEM), but only for perfect structures without any imperfection. In this paper, we developed an efficient numerical framework using nonlinear random network analysis (RNA) to verify how the statistical imperfections (geometrical and material property) contribute to the performance of general truss structures. The numerical results for kagome truss structures are compared with experimental measurements on 3-layerd WBK (wire-woven bulk kagome). The mechanical strength of the kagome structures is shown relatively stable with the Gaussian types of imperfections.
Machining Analysis of the Autofrettaged Compound Cylinder
Park, Jae-Hyun ; Kim, Jae-Hoon ; Cha, Ki-Up ; Hong, Suk-Kyun ; Lee, Young-Shin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 800~807
DOI : 10.3795/KSME-A.2007.31.7.800
Autofrettage process is used for internal forming and sizing of cylinder designed to withstand high internal pressures. Once the tube is autofrettaged, it needs to be machined to its final dimensions both at the bore and its outer surface. This paper presents an analytical analysis and numerical analysis of machined compound cylinder using finite element code, ANSYS10.0. An analytical model for predicting the level of autofrettage following either inner, outer, or combined machining of the compound cylinder is developed for the autofrettage residual stress field is simulated by an autofrettaged pressure. The autofrettaged pressures are obtained by using trying-error method. As autofrettage percentage is 20 % and 40 %, the numerical results are found to be in almost agreement with the analytical ones. However, as autofrettage percentage is 60 %, the numerical results have a little difference with the analytical ones.
A Study on the Shear Characteristics of Adhesives in Primary Mirror Supports of Satellite Camera
Kim, Hyun-Jung ; Seo, Yu-Deok ; Park, Sang-Hoon ; Youn, Sung-Kie ; Lee, Seung-Hoon ; Lee, Deog-Gyu ; Lee, Eung-Shik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 31, issue 7, 2007, Pages 808~815
DOI : 10.3795/KSME-A.2007.31.7.808
The optical performance of the mirror fur satellite camera is highly dependent on the adhesive properties between the mirror and its support. Therefore, in order to design a mirror with high optical performance, the mechanical properties of adhesives should be well defined. In this research, the mechanical properties of three kinds of space adhesives are studied. In case of the materials which show nearly incompressible behavior such as space adhesives, it is important to measure shear modulus which governs deviatoric stress components. Also the experiment should be performed in circumstances similar to real manufacturing process of mirror, because extra factors such as size effects, the adhesion effects of primer and reactions between adhesive and primer affect the properties of adhesive regions. In this research shear moduli of the adhesives are determined by using a single lap adhesively bonded joint. For the shear tests, several temperatures have been selected from
which is operating temperature range of the adhesive. In the case of linear behavior materials, shear moduli are calculated through a linear curve fitting. Shear stress-strain relation is obtained by using an exponential curve fitting for material which shows non-linear behavior. The shear modulus of each adhesive is expressed as a function of temperature. Characteristics and adaptability of the adhesives are discussed regarding their temperature sensitivity.