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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
An Effective Approach of Equivalent Elastic Method for Three-Dimensional Finite Element Analysis of Ceramic Honeycomb Substrates
Baek, Seok-Heum ; Cho, Seok-Swoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 223~233
DOI : 10.3795/KSME-A.2011.35.3.223
A ceramic monolithic catalyst is a honeycomb structure that consists of two layers. The honeycomb structure is regarded as a continuum in structure and heat-flow analysis. The equivalent mechanical properties of the honeycomb structure were determined by performing finite element analysis (FEA) for a test specimen. Bending strength experiments and FEA of the test specimen used in ASTM C1674-08 standard test were performed individually. The bonding coefficient between the cordierite ceramic layer and the washcoat layer was almost zero. The FEA test specimen was modeled on the basis of the bonding coefficient. The elastic modulus, Poisson's ratio, and the thermal properties of the ceramic monolithic substrate were determined by performing the FEA of the test specimen.
Behavior of Flexible Hose Connected to Mother Ship
Kim, Kun-Woo ; Lee, Jae-Wook ; Kim, Hyung-Ryul ; Yoo, Wan-Suk ; An, Deuk-Man ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 235~240
DOI : 10.3795/KSME-A.2011.35.3.235
A flexible hose attached to a mother ship experiences various motions that depend on the movement of the mother ship and that of underwater vehicle. Although the motion of the hose is a very important factor that determines how a mother ship should be steered in a real situation, it is difficult to experimentally obtain information about the hose motion. Therefore, we study the motion of the hose analytically. The ANCF(absolute nodal coordinate formulation) was used to model the hose, because this formulation can relax the Euler-Bernoulli theory and the Timoshenko beam theory and allow the deformation of the cross section. The mother ship is assumed to be a rigid body with 6 degrees of freedom. The motion of the hose is predominantly affected by the behavior of the mother ship and by the fluid flow.
Design of Gerotor Using Cycloid and Circular-Arc Curves
Choi, Tae-Hoon ; Kim, Moon-Saeng ; Lee, Geun-Su ; Jung, Sung-Yuen ; Kim, Chul ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 241~250
DOI : 10.3795/KSME-A.2011.35.3.241
The new gerotor developed in this paper has an inner rotor in which a circular arc is inserted between the hypocycloid and epicycloid curves, whereas the outer rotor is designed using the simulation results for the rotor and a modification method. The new gerotor has no cusps and loops and no limit on the eccentricity. We increase the average flow rate by adding a new design parameter,
, which is the inclined angle of the inner rotor at the intersection of the hypocycloid and the circular arc. A calculation method to calculate the chamber area is also developed. This method can also be used to calculate the flow rate and flow rate irregularity when the contact points are unknown. The control of eccentricity and
is expected to lead to an efficient rotor.
On the Statistical Properties of the Parameters B and q in Creep Crack Growth Law, da/dt=B(C
, in the Case of Mod. 9Cr-1Mo Steel
Kim, Seon-Jin ; Park, Jae-Young ; Kim, Woo-Gon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 251~257
DOI : 10.3795/KSME-A.2011.35.3.251
This paper deals with the statistical properties of parameters B and q in the creep crack growth rate (CCGR) law, da/dt=B
, in Mod. 9Cr-1Mo (ASME Gr.91) steel which is considered a candidate materials for fabricating next generation nuclear reactors. The CCGR data were obtained by creep crack growth (CCG) tests performed on 1/2-inch compact tension (CT) specimens under an applied load of 5000N at a temperature of
. The CCG behavior was analyzed statistically using the empirical equation between CCGR, da/dt and the creep fracture mechanics parameter,
. The B and q values were determined for each specimen by the least-squares fitting method. The probability distribution functions for B and q were investigated using normal, log-normal, and Weibull distributions. As far as this study is considered, it can be appeared that B and q followed the log-normal and Weibull distributions. Moreover, a strong positive linear correlation was found between B and q.
Sequential Approximate Optimization by Dual Method Based on Two-Point Diagonal Quadratic Approximation
Park, Seon-Ho ; Jung, Sang-Jin ; Jeong, Seung-Hyun ; Choi, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 259~266
DOI : 10.3795/KSME-A.2011.35.3.259
We present a new dual sequential approximate optimization (SAO) algorithm called SD-TDQAO (sequential dual two-point diagonal quadratic approximate optimization). This algorithm solves engineering optimization problems with a nonlinear objective and nonlinear inequality constraints. The two-point diagonal quadratic approximation (TDQA) was originally non-convex and inseparable quadratic approximation in the primal design variable space. To use the dual method, SD-TDQAO uses diagonal quadratic explicit separable approximation; this can easily ensure convexity and separability. An important feature is that the second-derivative terms of the quadratic approximation are approximated by TDQA, which uses only information on the function and the derivative values at two consecutive iteration points. The algorithm will be illustrated using mathematical and topological test problems, and its performance will be compared with that of the MMA algorithm.
Tribology of Si
Ceramics Depending on Amount of Added SiO
Nam, Ki-Woo ; Chung, Young-Kyu ; Hwang, Seok-Hwan ; Kim, Jong-Soon ; Moon, Chang-Kwon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 267~272
DOI : 10.3795/KSME-A.2011.35.3.267
We analyzed the wear characterization of
ceramics according to the amount of added
nanocolloid. The test specimen was prepared by hot-press sintering at 35 MPa and 2123 K in an
gas atmosphere for 1 h. A wear test was performed with a block-on-ring tester, and the test conditions were as follows: (1) the ring with a diameter of 35 mm had a rotational speed of 50 rpm; (2) the load was 9.8 N; and (3) the temperature was
. The test results show that
ceramics have a friction coefficient of about 1.0 and a wear loss of about 0.02 mm. Of the specimens used this study, the test specimen with 1.3 wt% of added
nanocolloid has the best wear resistance because it has the lowest friction coefficient and the smallest wear loss. This specimen also has the highest Vickers hardness and bending strength. In this study, the friction coefficient is inversely proportional to the hardness and bending strength.
Numerical Assessment of Dislocation-Punching Theories for Continuum Structural Analysis of Particle-Reinforced Metal Matrix Composites
Suh, Yeong-Sung ; Kim, Yong-Bae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 273~279
DOI : 10.3795/KSME-A.2011.35.3.273
The yield strength of particle-reinforced composites increases as the size of the particle decreases. This kind of length scale has been mainly attributed to the geometrically necessary dislocation punched around the particle as a result of the mismatch of the thermal expansion coefficients of the particle and the matrix when the composites are cooled down after consolidation. In this study, two dislocation-punching theories that can be used in continuum structural modeling are assessed numerically. The two theories, presented by Shibata et al. and Dunand and Mortensen, calculate the size of the dislocationpunched zone. The composite yield strengths predicted by finite element analysis were qualitatively compared with experimental results. When the size of the particle is less than
, the patterns of the composite strength are quite different. The results obtained by Shibata et al. are in qualitatively better agreement with the experimental results.
Minimum Safety Factor for Evaluation of Critical Buckling Pressure of Zirconium Alloy Tube
Kim, Hyung-Kyu ; Kim, Jae-Yong ; Yoon, Kyung-Ho ; Lee, Young-Ho ; Lee, Kang-Hee ; Kang, Heung-Seok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 281~287
DOI : 10.3795/KSME-A.2011.35.3.281
We consider the uncertainty in the elastic buckling formula for a thin tube. We take into account the measurement uncertainty of Young's modulus and Poisson's ratio and the tolerance of the tube thickness and diameter. Elastic buckling must be prohibited for a thin tube such as a nuclear fuel rod that must satisfy a self-stand criterion. Since the predicted critical buckling pressure overestimated that found in the experiment, the determination of the minimum safety factor is crucial. The uncertainty in each parameter (i.e., Young's modulus, Poisson's ratio, thickness, and diameter) is mutually independent, so the safety factor is evaluated as the sum of the inverse of each uncertainty. We found that the thickness variation greatly affects the uncertainty. The minimum safety factor of a thin tube of Zirconium alloy is evaluated as 1.547 for a thickness of 0.87 mm and 3.487 for a thickness of 0.254 mm.
Gaussian Kernel Smoothing of Explicit Transient Responses for Drop-Impact Analysis
Park, Moon-Shik ; Kang, Bong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 289~297
DOI : 10.3795/KSME-A.2011.35.3.289
The explicit finite element method is an essential tool for solving large problems with severe nonlinear characteristics, but its results can be difficult to interpret. In particular, it can be impossible to evaluate its acceleration responses because of severe discontinuity, extreme noise or aliasing. We suggest a new post-processing method for transient responses and their response spectra. We propose smoothing methods using a Gaussian kernel without in depth knowledge of the complex frequency characteristics; such methods are successfully used in the filtering of digital signals. This smoothing can be done by measuring the velocity results and monitoring the response spectra. Gaussian kernel smoothing gives a better smoothness and representation of the peak values than other approaches do. The floor response spectra can be derived using smoothed accelerations for the design.
Development of Pressure Observer to Measure Cylinder Length of Harbor-Construction Robot
Kim, Chi-Hyo ; Park, Kun-Woo ; Kim, Tae-Sung ; Lee, Min-Ki ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 299~308
DOI : 10.3795/KSME-A.2011.35.3.299
In this study, we develop a pressure observer to measure the cylinder length of a harbor-construction robot. For the robot control, sensors are required to measure the length of a hydraulic cylinder. The cylinder-position sensor is relatively expensive when the operating environment prohibits external approaches for the measurement of the cylinder position. LVDT or linear scales are usually mounted on the outside of the cylinder, which causes poor durability on a construction site. We use a pressure sensor to indirectly estimate the length of the cylinder. The pressure sensor is mounted inside a hydraulic valve box so that it is protected by the box and easy to waterproof for an underwater robot. By treating oil as a compressible fluid, we derive the nonlinear pressure dynamics as a function of the cylinder position, velocity, and pressure. The recursive least squares (RLS) algorithm is applied to identify the dynamic parameters, and the pressure observer estimates the cylinder position through the pressure acting on the head and the rod of the hydraulic cylinder. The position accuracy is relatively low, but it is acceptable for a construction robot that handles large armor stones.
Study on Structural Analysis and Manufacturing of Polyethylene Canoes
Park, Chan-Kyun ; Kim, Min-Gun ; Cho, Seok-Swoo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 309~316
DOI : 10.3795/KSME-A.2011.35.3.309
Canoes are usually made from wood or FRP. However, today environment-friendly materials are preferred, and hulls made of FRP are prohibited in some countries. Polyethylene can be recycled and so is suitable for synthetic canoe construction. We used 3D Boat-Design to determine the hydrostatic properties of the canoe. Flow-structure coupled analysis was performed using ANSYS Workbench R12.1. The hull pressure and passenger weight were considered as canoe loading factors. The key parameters for the canoe are the design variables. The constraints are as follows: (1) The maximum stress must not exceed 50% of the polyethylene yield stress; and (2) the canoe weight must not exceed 50 kg. The optimal structural conditions were obtained by the response optimization process. The components of the canoe hull were manufactured from polyethylene pipes and joined by thermal fusion methods. Tests showed that the polyethylene canoe had better performance than existing canoes.
Seismic Analysis of Nuclear Power Equipment Related to Design
Lee, Woo-Hyung ; Cho, Jong-Rae ; Roh, Min-Sik ; Ryu, Jeong-Hyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 317~323
DOI : 10.3795/KSME-A.2011.35.3.317
We use the finite element method to analyze the seismic design of a liquid storage tank for a polar crane at a nuclear power plant. We obtained the natural frequency and vibration modes by modal analysis, and we evaluated the seismic stability by response spectrum analysis. Furthermore, the seismic analysis of the tank was accomplished by analyzing not only the forces applied to the wall by the sloshing of the liquid, but also the safe-shutdown earthquake condition for the tank. We propose a seismic-design process and a seismic-analysis method for liquid storage tanks based on the commercial finite element analysis program, ANSYS.
A Study on the Promotion Time in Environmental Temperature Test
Han, Chul-Ho ; Kim, Kyoung-Hoon ; Kim, Hyoung-Eui ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 325~331
DOI : 10.3795/KSME-A.2011.35.3.325
A new method to predict the proper promotion time on the near-step-temperature test profile when heating or cooling the test-piece in a test chamber to the test temperature for environmental tests has been proposed by using the lumped analysis. For a given test condition the analysis shows the existence of a promotion time that reduces the testing time and saves energy. The theoretical results are in reasonably good agreements with experimental results for steel specimens. The suggested promotion time is approximately proportional to the mass/surface area of the test-piece for a given material.
End-Shape Effect for Stress Concentration Reduction of Composite Single-Lap Bonded Joint
Kim, Jung-Seok ; Hwang, Jae-Yeon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 35, issue 3, 2011, Pages 333~340
DOI : 10.3795/KSME-A.2011.35.3.333
We evaluated the stress-reduction effect for different shapes of a composite adherend with or without a spew fillet. Six different single-lap joint specimens were modeled and assessed using nonlinear finite element analysis. Moreover, we investigated the effect of the stiffness ratio of the adherend and adhesive. The single-lap joint with normal tapering had the highest stress values, and the single-lap joint with reverse tapering and a spew fillet had the lowest stress values. The composite adherends with higher stiffness had lower stress values, and the adhesives with lower stiffness had lower stress values.