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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
Journal Basic Information
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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Development and Evaluation of 6-components Force/Moment Generator
Chung, Hong Sik ; Joo, Jin Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 621~628
DOI : 10.3795/KSME-A.2016.40.7.621
This paper presents the development of a deadweight type 6-component force/moment generator for estimating characteristics of multi-component loadcell. Several new methods in moment generation are introduced in order to produce accurate force / moment and to minimize coupling effect between each force or moment components. In order to verify the reliability of the calibration system developed, estimation of the method for generating moment components and cross measurements between force or moment components are carried out utilizing a commercial torque cell and both-ends fixed beam designed in this paper.
Statistical Estimation of Motion Trajectories of Falling Petals Based on Particle Filtering
Lee, Jae Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 629~635
DOI : 10.3795/KSME-A.2016.40.7.629
This paper presents a method for predicting and tracking the irregular motion of bio-systems, - such as petals of flowers, butterflies or seeds of dandelion - based on the particle filtering theory. In bio-inspired system design, the ability to predict the dynamic motion of particles through adequate, experimentally verified models is important. The modeling of petal particle systems falling in air was carried out using the Bayesian probability rule. The experimental results show that the suggested method has good predictive power in the case of random disturbances induced by the turbulence of air.
A Study on the VHCF Fatigue Behaviors of Hydrogen Attacked Inconel 718 Alloy
Suh, Chang-Min ; Nahm, Seung-Hoon ; Kim, Jun-Hyong ; Pyun, Young-Sik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 637~646
DOI : 10.3795/KSME-A.2016.40.7.637
This study is to investigate the influence of hydrogen attack and UNSM on fatigue behaviors of the Inconel 718 alloy. The decrease of the fatigue life between the untreated and the hydrogen attacked material is 10-20%. The fatigue lives of hydrogen attacked specimen decreased without a fatigue limit, similar to those of nonferrous materials. Due to hydrogen embrittlement, about 80% of the surface cracks were smaller than the average grain size of
. Many small surface cracks caused by the embrittling effect of hydrogen attack were initiated at the grain boundaries and surface scratches. Cracks were irregularly distributed, grew, and then coalesced through tearing, leading to a reduction of fatigue life. Results revealed that the fatigue lives of UNSM-treated specimens were longer than those of the untreated specimens.
A Study on Scattered Wave Amplitude Closed-Form Solution Calculation of Torsional Wave Mode by Reciprocity Theorem
Lee, Jaesun ; Cho, Younho ; Achenbach, Jan D. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 647~652
DOI : 10.3795/KSME-A.2016.40.7.647
Guided waves can be used for the inspection of long range pipelines. Surface corrosion is often found as a major defect type in pipelines. The reciprocity relation is a well-established theorem by which one can simplify complicated mathematical expressions. The approach has been already applied to plate and half-space structures to obtain the closed-form solutions of scattered amplitude. However, results for the case of cylindrical structures have not been reported yet. In this paper, the scattering of torsional waves, which is widely used in commercial applications, is explored by the reciprocity theorem approach. Obtaining closed-form solutions of the amplitudes of propagating waves is much simplified by using the reciprocal relation. The scattered amplitudes for elliptical and rectangular defect shapes are calculated with respect to defect depth and width, at frequencies between 0 and 500 kHz. The amplitude shows the periodic result as a function of frequency. The derived closed-form solutions can play a significant role in quantitative signal interpretation.
A Study on the Effects on Low Cycle Fatigue Life of a High Pressure Turbine Nozzle due to the Perturbation of Crystal Orientation of Grain of DS Materials
Huh, Jae Sung ; Kang, Young Seok ; Rhee, Dong Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 653~658
DOI : 10.3795/KSME-A.2016.40.7.653
High pressure components of a gas turbine engine are generally made of nickel-base superalloys, using precision casting process due to complicated geometries with intricate channels and cooling holes. Turbine components manufactured from directionally solidified and single crystal materials have columnar grains; however, it is found that the crystals do not grow in its preferred direction, although the orientation can be controlled. This anisotropy can lead to the variations of elastic and Hill`s parameters in constitutive equations, and they alter stress distributions and the low cycle fatigue life. We aims to evaluate the effects of perturbed crystal orientations on the structural integrity of a directionally solidified nozzle using low cycle fatigue life. We also attempt to show the necessity for the control of allowed manufacturing errors and stochastic analysis. Our approaches included conjugate heat transfer and structural analysis, along with low cycle fatigue life assessment.
A Parallel Kalman Filter for Estimation of Magnetic Disturbance and Orientation Based on Nine-axis Inertial/Magnetic Sensor Signals
Lee, Jung Keun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 659~666
DOI : 10.3795/KSME-A.2016.40.7.659
Magnetic disturbance is one of the main factors that deteriorate the accuracy of orientation estimation methods based on inertial/magnetic sensor signals. This paper proposes a parallel Kalman filter(KF) that explicitly detects magnetic disturbances and thus can accurately estimate 3D orientation in magnetically disturbed environments. Due to the parallel nature of the proposed KF, even severe magnetic disturbances only affect yaw estimation, while roll and pitch values remain accurate. Consequently, the proposed KF can be effectively used in various applications that involve magnetically inhomogeneous environments, such as robots, ships, and planes.
Butt Weldability for SS400 Using Laser-Arc Hybrid Welding
Kim, Jong Do ; Myoung, Gi Hoon ; Park, In Duck ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 667~672
DOI : 10.3795/KSME-A.2016.40.7.667
This study presents results of an experimental investigation of the laser-arc, hybrid, butt welding process of SS400 structural steel. Welding parameters including laser power, welding current and speed were varied in order to obtain one-pass, full-penetration welds without defects. The conditions that resulted in optimal beads were identified. After welding, hardness measurements and microstructure observations were carried out in order to study weld properties. The mechanical properties of both the base material and welded specimen were compared based on the results of tensile strength measurements. The yield and tensile strengths were found to be similar.
Adhesive Strength of dry Adhesive Structures Depending on the Thickness of Metal Coating
Kim, Gyu Hye ; Kwon, Da Som ; Kim, Mi Jung ; Kim, Su Hee ; Yoon, Ji Won ; An, Tea Chang ; Hwang, Hui Yun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 673~677
DOI : 10.3795/KSME-A.2016.40.7.673
Recently, engineering applications have started to adopt solutions inspired by nature. The peculiar adhesive properties of gecko skin are an example, as they allow the animal to move freely on vertical walls and even on ceilings. The high adhesive forces between gecko feet and walls are due to the hierarchical microscopical structure of the skin. In this study, the effect of metal coatings on the adhesive strength of synthetic, hierarchically structured, dry adhesives was investigated. Synthetic dry adhesives were fabricated using PDMS micro-molds prepared by photolithography. Metal coatings on synthetic dry adhesives were formed by plasma sputtering. Adhesive strength was measured by pure shear tests. The highest adhesion strengths were found with coatings composed of 4 nm thick layers of Indium, 8 nm thick layers of Zinc and 6 nm thick layers of Gold, respectively.
A Study on Wire-rope Type Furnace Scaffolding and Its Lifting System for Large-sized Boiler
HA, Seung Woo ; Lee, Tae Ho ; Lee, Hae Seung ; Kim, Jeung Min ; You, Tai Woo ; Cho, Sun Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 679~683
DOI : 10.3795/KSME-A.2016.40.7.679
Boilers of large-sized coal-fired power plants are being operated under very poor conditions such as continuous operation or repeating of start-up and shutdown for a stable supply of electricity. Thus periodic inspection and maintenance are required to ensure reliability of operation. The loads of existing scaffolding systems for the maintenance of boilers are concentrated in the lower parts structurally, which may cause a serial collapse of the overall scaffolding system when there are problems in some members. Therefore, in this study, a safe furnace scaffolding system is developed by dispersing the loads in the upper part, as well as minimizing the hazards of serial collapsing. In addition, for cases where the direct installation of furnace scaffolding is challenging owing to the structure of the boiler tube, a lifting system for the installation of furnace scaffolding is developed so that furnace scaffolding can be supported to secure the integrity of the power generating facility.
Automation for Pick Arrangement Design of a Cutting Head Attachment Using RecurDyn/ProcessNet
Kang, Ji-Heon ; Jang, Jin-Seok ; Lee, Jae-Wook ; Kang, Hoon ; Kim, Kun-Woo ; Yoo, Wan-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 40, issue 7, 2016, Pages 685~692
DOI : 10.3795/KSME-A.2016.40.7.685
A cutting head is an attachment on the front of an excavator that cuts or grinds rocks. Cutting tools, called pick cutters, are arranged on the surface of the cutting head. The exact arrangement and configuration of pick cutters is one of the most important factors in determining grinding efficiency. This study focuses on the problem of automation for pick arrangement design, in order to make the design process more efficient and convenient. Design automation was carried out using RecurDyn/ProcessNet, and it was composed of three parts: `Drum set`, `Pick load`, and `Pick arrangement` sections. The presented method helps to decrease costs attributed to designing cutting heads and can be used to generate a wide range of attachment mechanisms.