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  • Title/Summary/Keyword: mechanical resistance

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Development of Membrane Film Pressure Sensor for Hot Roll Laminator (고온 롤 라미네이터용 멤브레인 구조 필름형 압력 센서 개발)

  • Kim, Do-Yeon;Lee, Tae-Kyung;Kang, Pil-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.6_2
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    • pp.1059-1065
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    • 2020
  • Demand for pressure sensors is increasing in various fields such as machinery, healthcare and medical care. A recent study is being conducted to create sensors that are more sensitive and have longer linear sections based on measurement principles. In this paper, a film-type sensor with a membrane structure was developed to measure the pressure distributed in the axial direction of a hot roll laminator. Performance of sensors was evaluated by resistance and durability according to membrane diameter. The resistance of the membrane sensor varies according to the contact state and contact area of the electrode. Therefore, the membrane diameter selection is important. Experiments showed the most pronounced variation in resistance under pressure at 8 mm in diameter of membrane. Reliability evaluation of sensors was carried out at room temperature and high temperature. The pressure on the sensor was pressurized 1000 times to measure the initial resistance and the resistance after the evaluation to analyze the change. Sensors showed stable results with low resistance changes of 5.15% and 6.27%, respectively. A large area sensor manufactured using the developed sensor also showed reliable results.

Three-dimensional numerical analysis of nonlinear phenomena of the tensile resistance of suction caissons

  • Azam, Arefi;Pooria, Ahad;Mehdi, Bayat;Mohammad, Silani
    • Geomechanics and Engineering
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    • v.32 no.3
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    • pp.255-270
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    • 2023
  • One of the main parameters that affect the design of suction caisson-supported offshore structures is uplift behavior. Pull-out of suction caissons is profoundly utilized as the offshore wind turbine foundations accompany by a tensile resistance that is a function of a complex interaction between the caisson dimensions, geometry, wall roughness, soil type, load history, pull-out rate, and many other parameters. In this paper, a parametric study using a 3-D finite element model (FEM) of a single offshore suction caisson (SOSC) surrounded by saturated soil is performed to examine the effect of some key factors on the tensile resistance of the suction bucket foundation. Among the aforementioned parameters, caisson geometry and uplift loading as well as the difference between the tensile resistance and suction pressure on the behavior of the soil-foundation system including tensile capacity are investigated. For this purpose, a full model including 3-D suction caisson, soil, and soil-structure interaction (SSI) is developed in Abaqus based on the u-p formulation accounting for soil displacement (u) and pore pressure, P.The dynamic responses of foundations are compared and validated with the known results from the literature. The paper has focused on the effect of geometry change of 3-D SOSC to present the soil-structure interaction and the tensile capacity. Different 3-D caisson models such as triangular, pentagonal, hexagonal, and octagonal are employed. It is observed that regardless of the caisson geometry, by increasing the uplift loading rate, the tensile resistance increases. More specifically, it is found that the resistance to pull-out of the cylinder is higher than the other geometries and this geometry is the optimum one for designing caissons.

Analysis of Grinding Characteristics of Ceramic (SiC) Materials (세라믹 소재의 연삭가공 특성 분석)

  • Park, Hwi-Keun;Park, Sang-Hyeon;Park, In-Seung;Yang, Dong-Ho;Cha, Seung-Hwan;Ha, Byeong-Cheol;Lee, Jong-Chan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.1
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    • pp.16-22
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    • 2018
  • Silicon carbide (SiC) is used in various semiconductor processes because it has superior thermal, mechanical, and electrical characteristics as well as higher chemical and corrosion resistance than existing materials. Due to these characteristics, various manufacturing technologies have been developed for SiC. A recent development among these technologies is Chemical Vapor Deposition SiC (CVD-SiC). Many studies have been carried out on the processing and manufacturing of CVD-SiC due to its different material characteristics compared to existing materials like RB-SiC or Sintered-SiC. CVD-SiC is physically stable and has excellent chemical and corrosion resistance. However, there is a problem with increasing the thickness, because it is manufactured through a deposition process. Additionally, due to its high strength and hardness, it is difficult to subject to machining.

A Study on Wear Characteristics of Machine Structural Steel by Surface Modification (표면개질에 의한 기계구조용강의 마멸특성에 관한 연구)

  • Park Heung-Sik;Woo Kyu-Sung
    • Tribology and Lubricants
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    • v.22 no.2
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    • pp.73-78
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    • 2006
  • The surface modification of automobile parts is of great technological importance for the improvement of corrosion resistance, wear resistance, fatigue strength and so on. Recently, research on the development of the technology of surface modification substituting 6-balance chrome process has progressively been achieved in automobile parts. Although the innovation technology for the improvement of the corrosion-resisting and wear resistant properties through post oxidation after nitrocarburising process had attracted a great attention. For this, anodically potentiodynamic polarisation testing was carried out to corrosion resistance and friction and wear experiment according to applied load and sliding distance was carried out to evaluate the wear resistance of machine structural steel with nitrocarburising and non-nitrocarburising SM45C. The presumed wear volume was calculated with the image processing far evaluation of wear resistance of two materials. The results show that the nitrocarburising had a distinguished corrosion resistance and wear resistance than non-nitrocarburising.

Sustainable self compacting acid and sulphate resistance RAC by two stage mixing approaches

  • Rajhans, Puja;Kisku, Nishikant;Nayak, Sanket;Panda, Sarat Kumar
    • Advances in concrete construction
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    • v.9 no.1
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    • pp.55-70
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    • 2020
  • In this research article, acid resistance, sulphate resistance and sorptivity of self compacted concrete (SCC) prepared from C&D waste have been discussed. To improve the above properties of self compacted recycled aggregate concrete (SCRAC) along with mechanical and durability properties, different two stage mixing approaches (TSMA and TSMAsfc) were followed. In the proposed two stage mixing approach (TSMAsfc), silica fume, a proportional amount of cement and a proportional amount of water were mixed in premix stage which fills the pores and cracks of recycled aggregate concrete (RAC). The concrete specimen prepared using above mixing approaches were immersed in 1% concentration of sulphuric acid (H2SO4) and magnesium sulphate (MgSO4) solution for 28, 90 and 180 days for evaluating the acid resistance of SCRAC. Experimental results concluded that the proposed two stage mixing approach (TSMAsfc) is most suitable for acid resistance and sulphate resistance in terms of weight loss and strength loss due to the elimination of pores and cracks in the interfacial transition zone (ITZ). In modified two stage mixing approach, the pores and cracks of recycled concrete aggregate (RCA) were filled up and make ITZs of SCRAC stronger. Microstructure analysis was carried out to justify the reason of improvement of ITZs by electron probe micro analyser (EPMA) analysis. X-ray mapping was also done to know the presence of strength contributing elements presents in the concrete sample. It was established that SCRAC with modified mixing approach have shown improved results in terms of acid resistance, sulphate resistance, sorptivity and mechanical properties.

Surface Modification of Aluminum by Nitrogen-Ion Implantation

  • Kang Hyuk-Jin;Ahn Sung-Hoon;Lee Jae-Sang;Lee Jae-Hyung
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.1
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    • pp.57-61
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    • 2006
  • The research on surface modification technology has been advanced to improve the properties of engineering materials. Ion implantation is a novel surface modification technology that enhances the mechanical, chemical and electrical properties of substrate's surface using accelerated ions. In this research, nitrogen ions were implanted into AC7A aluminum substrates which would be used as molds for rubber molding. The composition of nitrogenion implanted aluminum and distribution of nitrogen ions were analyzed by Auger Electron Spectroscopy (AES). To analyze the modified surface, properties such as hardness, friction coefficient, wear resistance, contact angle, and surface roughness were measured. Hardness of ion implanted specimen was higher than that of untreated specimen. Friction coefficient was reduced, and wear resistance was improved. From the experimental results, it can be expected that implantation of nitrogen ions enhances the mechanical properties of aluminum mold.

Evaluation of the Wear Resistance of PVD Coatings on Drills by Using a Slurry Jet Impact Test

  • Iwai, Y.;Ueno, Y.;Suehiro, T.;Honda, T.;Hogmark, S.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.141-142
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    • 2002
  • In this paper, we propose a slurry jet (water containing 1μm alumina particles) impact test in order to quickly evaluate the wear properties of physical vapor deposited (PVD) coatings on commercial cutting tools. Linear wear was obtained for bothe coating and substrate material, and the penetration through the coating into the substrate was signified by a sharp increase in slope of the wear versus time curve. The PVD coatings deposited on the tools showed the same wear rates as those on reference plate specimens produced by the same coating methods. We conclude that our proposed evaluation technique for coatings is considerably useful as a screening test when evaluating coated tools like twist drills, taps, end mills, gear hobs, etc.

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Study on the fluid resistance coefficient for control simulation of an underwater vehicle (수중로봇 제어 시뮬레이션을 위한 유체저항계수 연구)

  • Park, Sang-Wook;Kim, Min-Soo;Sohn, Jeong-Hyun;Baek, Woon-Kyung
    • Journal of Power System Engineering
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    • v.20 no.1
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    • pp.24-29
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    • 2016
  • Remotely operated vehicles or autonomous underwater vehicles have been used for exploiting seabed natural resources. In this study, the autonomous underwater vehicle of hovering type(HAUV) is developed to observe underwater objects in close distance. A dynamic model with six degrees of freedom is established, capturing the motion characteristics of the HAUV. The equations of motion are generated for the dynamic control simulation of the HAUV. The added mass, drag and lift forces are included in the computer model. Computational fluid dynamics simulation is carried out using this computer model. The drag coefficients are produced from the CFD.

The Carbonization Behaviors of Coal Tar Pitch for Mechanical Seal

  • Chae, Jae-Hong;Kim, Kyung-Ja;Cho, Kwang-Youn;Choi, Jae-Young
    • Carbon letters
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    • v.2 no.3_4
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    • pp.182-191
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    • 2001
  • Quinoline insoluble formed by the heat treatment was hot-pressed near its softening point. The green body was stabilized in the temperature range of 300400C and subsequently carbonized below 1300C in an argon atmosphere. The behaviors of QI formation was examined with varying the heat treatment temperature and the lapse of time of the sample carbonized at various temperatures. And the mechanical property, corrosion resistance, and friction behavior were also measured optimum content of mesophase pitch ensured a dense structure and high LC(002) value, which resulted in high mechanical properties, good corrosion resistance, and low-stable friction behavior.

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Touchpad for Force and Location Sensing

  • Kim, Dong-Ki;Kim, Jong-Ho;Kwon, Hyun-Joon;Kwon, Young-Ha
    • ETRI Journal
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    • v.32 no.5
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    • pp.722-728
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    • 2010
  • This paper presents the design and fabrication model of a touchpad based on a contact-resistance-type force sensor. The touchpad works as a touch input device, which can sense contact location and contact force simultaneously. The touchpad is 40 mm wide and 40 mm long. The touchpad is fabricated by using a simple screen printing technique. The contact location is evaluated by the calibration setup, which has a load cell and three-axis stages. The location error is approximately 4 mm with respect to x-axis and y-axis directions. The force response of the fabricated touchpad is obtained at three points by loading and unloading of the probe. The touchpad can detect loads from 0 N to 2 N. The touchpad shows a hysteresis error rate of about 11% and uniformity error rate of about 3%.