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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 40, Issue 9 - Sep 2016
Volume 40, Issue 8 - Aug 2016
Volume 40, Issue 7 - Jul 2016
Volume 40, Issue 6 - Jun 2016
Volume 40, Issue 5 - May 2016
Volume 40, Issue 4 - Apr 2016
Volume 40, Issue 3 - Mar 2016
Volume 40, Issue 2 - Feb 2016
Volume 40, Issue 1 - Jan 2016
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Tensile and Fatigue Behavior of ASS304 for Cold Stretching Pressure Vessels at Cryogenic Temperature
Choi, Hoon Seok ; Kim, Jae Hoon ; Na, Seong Hyun ; Lee, Youn Hyung ; Kim, Sung Hun ; Kim, Young Kyun ; Kim, Ki Dong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 429~435
DOI : 10.3795/KSME-A.2016.40.5.429
Cold stretching(CS) pressure vessels from ASS304 (austenitic stainless steel 304) are used for the transportation and storage of liquefied natural gas(LNG). CS pressure vessels are manufactured by pressurizing the finished vessels to a specific pressure to produce the required stress
. After CS, there is some degree of plastic deformation. Therefore, CS vessels have a higher strength and lighter weight compared to conventional vessels. In this study, we investigate the tensile and fatigue behavior of ASS304 sampled by CS pressure vessels in accordance with the ASME code at cryogenic temperature. From the fatigue test results, we show S-N curves using a statistical method recommended by JSEM-S002. We carried out the fractography of fractured specimens using scanning electron microscopy (SEM).
3D Finite Element Simulation of Pellet-Cladding Mechanical Interaction
Seo, Sang Kyu ; Lee, Sung Uk ; Lee, Eun Ho ; Yang, Dong Yol ; Kim, Hyo Chan ; Yang, Yong Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 437~447
DOI : 10.3795/KSME-A.2016.40.5.437
In a nuclear power plant, the fuel assembly, which is composed of fuel rods, burns, and the high temperature can generate power. The fuel rod consists of pellets and a cladding that covers the pellets. It is important to understand the pellet-cladding mechanical interaction with regard to nuclear safety. This paper proposes simulation of the PCMI. The gap between the pellets and the cladding, and the contact pressure are very important for conducting thermal analysis. Since the gap conductance is not known, it has to be determined by a suitable method. This paper suggests a solution. In this study, finite element (FE) contact analysis is conducted considering thermal expansion of the pellets. As the contact causes plastic deformation, this aspect is considered in the analysis. A 3D FE module is developed to analyze the PCMI using FORTRAN 90. The plastic deformation due to the contact between the pellets and the cladding is the major physical phenomenon. The simple analytical solution of a cylinder is proposed and compared with the fuel rod performance code results.
Finite Element Analysis for Friction Noise with Respect to the Friction Curve of Several Materials
Baek, Jongsu ; Nam, Jaehyeon ; Do, Hyuncheol ; Kang, Jaeyoung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 449~455
DOI : 10.3795/KSME-A.2016.40.5.449
This study provides the finite-element (FE) squeal-model predicting friction-induced noise with respect to several friction materials that have different friction characteristics. The friction curve and the corresponding friction noise were measured for four friction materials (Cu, Ni, Al, Mg) using the pin-on-disk and reciprocating friction system. The slope of the friction curve linearized at the sliding velocity was applied to the FE model. The unstable modes in the complex eigenvalue analysis were shown to correspond to the squeal frequencies that existed in the experiment.
A Study on the Kinetic Energy and Dispersion Behavior of High-velocity Impact-induced Debris Using SPH Technique
Sakong, Jae ; Woo, Sung-Choong ; Kim, Tae-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 457~467
DOI : 10.3795/KSME-A.2016.40.5.457
In this study, we investigate the dispersion behavior of debris and debris cloud generated by high-velocity impacts using the smoothed particle hydrodynamics (SPH) technique. The projectile and target plate were made of aluminum, and we confirm the validity of the SPH technique by comparing the measured major and minor axis lengths of the debris cloud in the reference with the predicted values obtained through the SPH analysis. We perform high-velocity impact and fracture analysis based on the verified SPH technique within the velocity ranges of 1.5~4 km/s, and we evaluate the dispersion behavior of debris induced by the impact in terms of its kinetic energy. The maximum dispersion radius of the debris on the witness plates located behind the target plate was increased with increasing impact velocity. We derive an empirical equation that is capable of predicting the dispersion radius, and we found that 95％ of the total kinetic energy of the debris was concentrated within 50％ of the maximum dispersion radius.
Impact Force Applied on the Spent Nuclear Fuel Disposal Canister that Accidentally Drops and Collides onto the Ground
Kwon, Young Joo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 469~481
DOI : 10.3795/KSME-A.2016.40.5.469
In this paper, a mathematical methodology was theoretically studied to obtain the impact force caused by the collision between rigid bodies. This theoretical methodology was applied to compute the impact force applied on the spent nuclear fuel disposal canister that accidentally drops and collides onto the ground. From this study, the impact force required to ensure a structurally safe canister design was theoretically formulated. The main content of the theoretical study concerns the rigid body kinematics and equation of motion during collision between two rigid bodies. On the basis of this study, a general impact theory to compute the impact force caused by the collision between two bodies was developed. This general impact theory was applied to theoretically formulate the approximate mathematical solution of the impact force that affects the spent nuclear fuel disposal canister that accidentally falls to the ground. Simultaneously, a numerical analysis was performed using the computer code to compute the numerical solution of the impact force, and the numerical result was compared with the approximate mathematical solution.
Global Sensitivity Analysis of Joints for Plug-in Digital Framework
Lee, Dooho ; Won, Young-Woo ; Kwon, Jong-Hyun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 483~488
DOI : 10.3795/KSME-A.2016.40.5.483
Plug-In Digital Framework is a system response analysis tool that is employed when system components are composed of black-box modules. Generally, the dynamic characteristics of joints between the system components significantly affect system responses, and they lead to displacement- and frequency-dependent stiffness and loss factor. Thus, the sensitivity of each joint parameters should be estimated from a global perspective. In this study, we introduce a global sensitivity analysis procedure under the Plug-In Digital Framework. To efficiently calculate the system responses, we introduce the frequency response function (FRF)-based substructuring method. Using the random balance designs (RBD), we generate the system responses and estimate the global first-order sensitivities for each joint stiffness. We apply the proposed global sensitivity analysis method to an interior noise problem of a passenger car, and we evaluate the efficiency of the global sensitivity analysis method.
Mode Characteristics of Spur Gears and Ball-Bearing Stiffness
Park, Chan IL ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 489~495
DOI : 10.3795/KSME-A.2016.40.5.489
This study focuses on a detailed ball-bearing model for spur gears. The nonlinear ball-bearing stiffness with radial clearance is derived and calculated. The bearing stiffness is used to the 3-degree-of-freedom (DOF) spur gear system model. The mode characteristics of the gear system model are analyzed and verified by performing finite-element analysis (FEA). From the results, the bearing stiffness on the radial clearance was more sensitive under low-load conditions compared to high-load conditions. The bearing stiffness significantly affected the gear dynamics in the low-frequency region, while the mesh stiffness affected the high natural frequency.
Optimal Muffler Design Considering the Insertion Loss Calculated Outside the Duct
Lee, Jong Kyeom ; Oh, Kee Seung ; Lee, Jin Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 497~503
DOI : 10.3795/KSME-A.2016.40.5.497
In this study, we formulate an acoustical topology optimization problem to optimally design a partition layout inside the expansion chamber of a muffler. The lower-limit insertion loss value at a target frequency is constrained, and the partition volume is selected as an object function. In this study, we calculate the insertion loss outside the duct, while to determine the noise-attenuation performance, we use the insertion loss value calculated inside the duct or transmission loss value obtained in a previous study. We employ the finite-element model for acoustical analysis, and we determine the transmission of an incident acoustic wave through each finite element using the functions of design variables that change continuously between "0" and "1." The rigid body elements, which totally reflect incident waves, build up partitions. Finally, we compare optimal topologies that depend on the target frequency and the allowed lower-limit value of insertion loss.
Three-Dimensional Thermoforming Analysis of an Inner Case with Three Cavities for Refrigerator
Lee, Ho Jin ; Ahn, Dong Gyu ; Lee, Sang Hun ; Ki, Jun Chul ; Ko, Jae Hong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 505~511
DOI : 10.3795/KSME-A.2016.40.5.505
The aim of this study is to investigate the thermoforming characteristics of an inner case with three refrigerator cavities using three-dimensional(3D) thermoforming analyses. We perform fundamental formability analyses using a 3D model of the mould for the inner case. We carry out tensile tests at the elevated temperature to examine the properties and characteristics of the thermoformed material. Then, we design sub-processes of the thermoforming process for the inner case. In addition, we develop suitable finite-element models for different sub-processes. We investigate the deformed shapes and thickness distributions of the inner case for different sub-processes using the results of the thermoforming analysis. Finally, we discuss the formability and thermoforming characteristics of the inner case with three cavities.
Stress Concentration Factor and Stress Intensity Factor with U-notch and Crack in the Beam
Seo, Bo Seong ; Lee, Kwang Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 513~523
DOI : 10.3795/KSME-A.2016.40.5.513
The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and phtoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1~2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used. where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length a(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.
Study on the Remote Controllability of Vision Based Unmanned Vehicle Using Virtual Unmanned Vehicle Driving Simulator
Kim, Sunwoo ; Han, Jong-Boo ; Kim, Sung-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 5, 2016, Pages 525~530
DOI : 10.3795/KSME-A.2016.40.5.525
In this paper, we proposed an image shaking index to evaluate the remote controllability of vision based unmanned vehicles. To analyze the usefulness of the proposed image-shaking index, we perform subjective tests using a virtual unmanned vehicle driving simulator. The developed driving simulator consists of a real-time multibody dynamic software of the unmanned vehicle, a motion simulator, and a driver console. We perform dynamic simulations to obtain the motion of the unmanned vehicle running on the various road surfaces such as ISO roughness level A~E roads. The motion of the vehicle body is reflected in the motion simulator. Then, to enable remote control operation, we offer to operators the image data that was measured using the camera sensor on the simulator. We verify the usefulness of the proposed image-shaking index compared with subjective index provided by operators.