Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Transactions of the Korean Society of Mechanical Engineers A
Journal Basic Information
Journal DOI :
The Korean Society of Mechanical Engineers
Editor in Chief :
Volume & Issues
Volume 39, Issue 12 - Dec 2015
Volume 39, Issue 11 - Nov 2015
Volume 39, Issue 10 - Oct 2015
Volume 39, Issue 9 - Sep 2015
Volume 39, Issue 8 - Aug 2015
Volume 39, Issue 7 - Jul 2015
Volume 39, Issue 6 - Jun 2015
Volume 39, Issue 5 - May 2015
Volume 39, Issue 4 - Apr 2015
Volume 39, Issue 3 - Mar 2015
Volume 39, Issue 2 - Feb 2015
Volume 39, Issue 1 - Jan 2015
Selecting the target year
A Study on the Development of Impact Analysis Model of Roll Control System for Course Correction Munition
Ko, Jun Bok ; Yun, Chan Sik ; Kim, Yong Dae ; Kim, Wan Joo ; Cho, Seung Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 737~742
DOI : 10.3795/KSME-A.2015.39.8.737
Course correction munition are a weapson system for precision attacks and are assembled by applying a ballistic control system to existing projectiles. The roll control system is a subsystem of the ballistic control system and is placed between the guidance and control units inside of the projectile, which undergoes a 5000g lateral acceleration. Thus, it is very important to design the system to endure this load. Many developed countries evaluate the performance and safety of course correction munitions' parts using live-fire gun launch tests or a soft recovery system. However, these methods are expensive and slow. Thus, in this study, we develop impact analysis model of the roll control system using CAE. We apply the code to simulate impact phenomenon and use Johnson-Cook material model for modeling the high strain rate effect on the materials. We also design bearings in detail to analyze their behavior and verify the reliability of CAE model through gas-gun impact tests of the roll control system.
Dynamic Tumble Stability Analysis of Seabed Walking Robot in Forward Incident Currents
Jun, Bong-Huan ; Shim, Hyungwon ; Yoo, Seongyeol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 743~749
DOI : 10.3795/KSME-A.2015.39.8.743
In this paper, we describe the dynamic tumble-stability analysis of a seabed-walking robot named Crabster (CR200) in forward-incident currents. CR200 is designed to be operated in tidal-current conditions, and its body shape is also designed to minimize hydrodynamic resistances considering hydrodynamics. To analyze its tumble stability, we adopt the dynamic stability margin of a ground-legged robot and modify the definition of the margin to consider tidal-current effects. To analyze its dynamic tumble stability, we use the estimated hydrodynamic forces that act on the robot in various tidal-current conditions, and analyze the dynamic tumble-stability margin of the robot using the estimated results obtained for the various tidal-current conditions. From the analyses, we confirm the improved tumble stability of the robot according to the movement of the tumble axis caused by the supporting points of the legs.
Statistical Calibration and Validation of Mathematical Model to Predict Motion of Paper Helicopter
Kim, Gil Young ; Yoo, Sung Bum ; Kim, Dong Young ; Kim, Dong Seong ; Choi, Joo Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 751~758
DOI : 10.3795/KSME-A.2015.39.8.751
Mathematical models are actively used to reduce the experimental expenses required to understand physical phenomena. However, they are different from real phenomena because of assumptions or uncertain parameters. In this study, we present a calibration and validation method using a paper helicopter and statistical methods to quantify the uncertainty. The data from the experiment using three nominally identical paper helicopters consist of different groups, and are used to calibrate the drag coefficient, which is an unknown input parameter in both analytical models. We predict the predicted fall time data using probability distributions. We validate the analysis models by comparing the predicted distribution and the experimental data distribution. Moreover, we quantify the uncertainty using the Markov Chain Monte Carlo method. In addition, we compare the manufacturing error and experimental error obtained from the fall-time data using Analysis of Variance. As a result, all of the paper helicopters are treated as one identical model.
Study on the Effect of Thermal Property of Metals in Ultrasonic-Assisted Laser Machining
Lee, Hu Seung ; Kim, Gun Woo ; Park, Jong Eun ; Yang, Min Yang ; Cho, Sung Hak ; Park, Jong Kweon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 759~763
DOI : 10.3795/KSME-A.2015.39.8.759
The laser machining process has been proposed as an advanced process for the selective fabrication of electrodes without a mask. In this study, we adapt laser machining to metals that have different thermal properties. Based on the results, the metals exhibit a different surface morphology, heat-affected zone (HAZ), and a recast layer around the machined surface according to their thermal conductivity, boiling point, and thermal diffusivity. Then, we apply ultrasonic-assisted laser machining to remove the recast layer. The ultrasonic-assisted laser machining exhibits a better surface quality in metals with higher diffusivity than those having lower diffusivity.
Investigation of Friction and Wear Characteristics of Cast Iron Material Under Various Conditions
Joo, Ji-Hoon ; Kim, Chang-Lae ; Nemati, Narguess ; Oh, Jeong-Taek ; Kim, Dae-Eun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 765~772
DOI : 10.3795/KSME-A.2015.39.8.765
Cast iron is widely used in fields such as the transport and heavy industries. For parts where contact damage is expected to occur, it is necessary to understand the friction and wear characteristics of cast iron. In this study, we use cast iron plates as the specimens to investigate their friction and wear characteristics. We perform various experiments using a reciprocating type tribotester. We assess the frictional characteristics by analyzing the friction coefficient values that were obtained during the sliding tests. We observe the wear surfaces of cast iron and steel balls using a scanning electron microscope, confocal microscope, and 3d profiler. We investigate the friction and wear characteristics of cast iron by injecting sand and alumina particles having various sizes. Furthermore, we estimate the effect of temperature on the friction and wear characteristics. The results obtained are expected to aid in the understanding of the tribological characteristics of cast iron in industry.
A Study on the Mechanical Properties of Additive Manufactured Polymer Materials
Kim, Dongbum ; Lee, In Hwan ; Cho, Hae Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 773~780
DOI : 10.3795/KSME-A.2015.39.8.773
Traditionally, additive manufacturing (AM) technology has been used to fabricate prototypes in the early development phase of a product. This technology is being applied to release manufacturing of a product because of its low cost and fast fabrication. AM technology is a process of joining materials to fabricate a product from the 3D CAD data in a layer-by-layer manner. The orientation of a layer during manufacturing can affect the mechanical properties of the product because of its anisotropy. In this paper, tensile testing of polymer-based specimens were built with a typical AM process (FDM, PolyJet and SLA) to study the mechanical properties of the AM materials. The ASTM D 638 tensile testing standard was followed for building the specimens. The mechanical properties of the specimens were determined on the basis of stress-strain curves formed by tensile tests. In addition, the fracture surfaces of the specimens were observed by SEM to analyze the results.
Durability Assessment of Polyoxymethylen Using Ultrasonic Fatigue Testing
Cho, In Sik ; Hwang, Jung Ho ; Oh, Joo Yeon ; Kim, Hyun Chang ; Oh, Sae Hoon ; Lee, Chang Soon ; Park, In Gyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 781~785
DOI : 10.3795/KSME-A.2015.39.8.781
In this study, a newly developed ultrasonic fatigue test was performed for durability assessment of polyoxymethylene engineering plastic, which has a high crystallization rate and degree of crystallization. Fatigue strength of POM (polyoxymethylene) was performed on a piezoelectric UFT developed by Mbrosia Co., Ltd(1), operating at a high frequency of 20 kHz. The test results showed a fatigue limit of 5.0~6.0 MPa under fatigue testing at R = -1, 20kHz; and, electron microscopy revealed the size effect by risk volume and fractured dimple structure after the coalescence of micro-voids through the crazing effect, which occurs during the failure of a polymer.
A Study on The Change of Insert Clamping Force Influence According to the Surface Treatment of Armor Aluminum Alloy Plate
Hwang, Bu Il ; Yang, Sang Hun ; Kim, Chi Hwan ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 787~791
DOI : 10.3795/KSME-A.2015.39.8.787
In some cases which are unable to replace the inserts when the depot maintenance or performance improvement of armored vehicles are carried out could have a risk of declining clamping forces by re-processing chromate. The change in the clamping forces of inserts has been investigated by applying a chromate process to hold the insert on the aluminum plate of the armored vehicle in this paper. In order to identify the effect of types and surface treatment, the breaking strength has been measured by the equivalent test item to the actual conditions. These tests would contribute the establishment of the armored vehicle production process.
Computational and Experimental Analyses of the Wave Propagation Through a Bar Structure Including Liquid-Solid Interface
Park, Sangjin ; Rhee, Huinam ; Yoon, Doo Byung ; Park, Jin Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 793~799
DOI : 10.3795/KSME-A.2015.39.8.793
In this research, we study the propagation of longitudinal and transverse waves through a metal rod including a liquid layer using computational and experimental analyses. The propagation characteristics of longitudinal and transverse waves obtained by the computational and experimental analyses were consistent with the wave propagation theory for both cases, that is, the homogeneous metal rod and the metal rod including a liquid layer. The fluid-structure interaction modeling technique developed for the computational wave propagation analysis in this research can be applied to the more complex structures including solid-liquid interfaces.
Evaluation of Datum Unit for Diagnostics of Journal-Bearing Systems
Jeon, Byungchul ; Jung, Joonha ; Youn, Byeng D. ; Kim, Yeon-Whan ; Bae, Yong-Chae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 801~806
DOI : 10.3795/KSME-A.2015.39.8.801
Journal bearings support rotors using fluid film between the rotor and the stator. Generally, journal bearings are used in large rotor systems such as turbines in a power plant, because even in high-speed and load conditions, journal bearing systems run in a stable condition. To enhance the reliability of journal-bearing systems, in this paper, we study health-diagnosis algorithms that are based on the supervised learning method. Specifically, this paper focused on defining the unit of features, while other previous papers have focused on defining various features of vibration signals. We evaluate the features of various lengths or units on the separable ability basis. From our results, we find that one cycle datum in the time-domain and 60 cycle datum in the frequency domain are the optimal datum units for real-time journal-bearing diagnosis systems.
Electrochemical Simulation for Limited-Discharge Current Prediction of Li-ion Secondary Cell Using High-Rate Discharge
Kim, Simon ; Lee, Young Shin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 807~812
DOI : 10.3795/KSME-A.2015.39.8.807
Li-ion batteries are energy sources that are widely used in applications such as notebooks, cellular phones, power tools, and vehicles. They are devices in which stored chemical energy is changed to electrical energy by electrochemical reactions. They have a high energy density, small size, and are lightweight. In particular, power tools and vehicles require high charge/discharge rates. Therefore, in this paper, we perform electrochemical simulations using a commercial finite-element analysis program to determine the high discharge-rate characteristics of Li-ion cells. In addition, by performing high discharge-rate simulations, we found that the limited discharge current was 63 A. Based on the results obtained, we investigate the behavior of Li-ion cells with a high rate of discharge.
Study on Temperature Control and Optimal Design for Continuous Sterilizer
Park, Cheol Jae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 813~821
DOI : 10.3795/KSME-A.2015.39.8.813
In this paper, we analyzed the problems of a batch-type sterilizer and design a continuous sterilizer to control the temperature deviation. The temperature deviation is analyzed with respect to design parameters such as a nozzle diameter, hole diameter, and nozzle length. The significant temperature parameters are optimized using the response surface methodology. An experimental apparatus is developed using the optimized design parameters. Using a field test, we show that the target temperature is obtained in about 7.3 minutes and the temperature deviation is improved about
. The optimized parameters from the test are equal to the analytical parameters.
Structural Optimization Using Equivalent Static Loads and Substructure Synthesis Method
Choi, Wook Han ; Na, Yoo Sang ; Park, Gyung-Jin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 39, issue 8, 2015, Pages 823~830
DOI : 10.3795/KSME-A.2015.39.8.823
Structural optimization pursues improved performance of structures. Nowadays, structural optimization is applied to the design of huge and complex structures such as an airplane. As the number of the finite elements is increased, the analysis solution becomes more accurate. However, the design cost using the finite element model is significantly increased. The component mode synthesis method that is using the substructure synthesis method is frequently employed in order to keep the accuracy and reduce the cost. A new design method for structural optimization is proposed to reduce the design cost and to consider the dynamic effect of the structure. The proposed method reduces the design cost by applying the equivalent static loads on the design domain. An example of linear dynamic response optimization is solved and the efficiency of the proposed method is demonstrated.