• Title/Summary/Keyword: 상어표피

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3D Elastic Contact Analysis of Sharkskin Surface Pattern (상어 표피 형상의 3차원 탄성접촉해석)

  • Kim, Tae Wan
    • Tribology and Lubricants
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    • v.28 no.6
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    • pp.297-302
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    • 2012
  • We conducted 3D elastic contact analysis of a sharkskin surface pattern for the characteristic assessment of biomimetic shark skin structure pattern for engineering applications. Rough sharkskin surfaces of similar size with real shark skin scales are generated numerically. Under the assumption of the contact of a plate on the generated sharkskin surface, contact performances such as contact pressure, real contact area, and surface separation are evaluated.

Wettability of Biomimetic Riblet Surface like Sharkskin (상어 표피 모사 리블렛 구조의 젖음성 평가)

  • Kong, Yu Sik;Kim, Tae Wan
    • Tribology and Lubricants
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    • v.29 no.5
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    • pp.304-309
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    • 2013
  • Shark skin has functionalities such as self-cleaning and antifouling; it also exhibits excellent drag reduction owing to a hierarchical structure of microgrooves and nanometer-long chain mucus drag reduction interfaces around the shark body. In this study, the wettability of a shark skin surface and its replicas are evaluated. First, a shark skin template is taken from a real shark. Then, shark skin replicas are produced directly from a shark skin template, using a micromolding technique. The quantitative replication precision of the shark skin replicas is evaluated by comparing the geometry of the shark skin template to the replica using 2D surface profiles. Contact angles at the solid-air-water interfaces are evaluated for the shark skin template and its replicas under two conditions: with and without hydrophobic coating. The results show that the microriblets on shark skin improve the hydrophobic feature and play a critical role in self-cleaning.

Fabrication of a Micro-riblet Shark Skin-like Surface using a WEDM Process (와이어 방전가공을 이용한 상어 표피 모사 리블렛 표면 제작)

  • Park, Young Whan;Kim, Tae Wan
    • Tribology and Lubricants
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    • v.32 no.6
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    • pp.201-206
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    • 2016
  • In this study, we attempt to produce a semi-elliptical riblet with a shark skin-like surface using wire electrical discharge machining (WEDM) and micro molding techniques. Our design for the production of the semi-elliptical mold includes an electrode, a winding roller, and a guide on the WEDM system. A replication mold with negative riblets is machined using WEDM, and a shark skin inspired surface with positive riblets is fabricated using a micro molding technique. For a comparison with the original shark skin, a shark skin replica is also produced using the micro molding technique directly from a shark skin template. Droplet contact angles on a flat surface, the shark skin replica, and the epoxy resin-based micro riblet shark skin-like surface are evaluated. The effect of a Teflon coating on the contact angles for the three different surfaces is also investigated. The results show the micro riblet with a shark skin-like surface has a similar contact angle as the shark skin replica, which means that the simplified riblet shark skin surface strongly influences the performance of wettability. This study confirms the effectiveness of using the WEDM method to prepare hydrophobic surfaces with diverse surface patterns.

Elasto-hydrodynamic Lubrication Analysis for Biomimetic Riblet Surface like Shark Skin (상어표피 모사 리블렛 구조의 탄성유체윤활 해석)

  • Kim, Tae-Wan
    • Journal of Power System Engineering
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    • v.18 no.1
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    • pp.128-134
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    • 2014
  • For the characteristic assessment of biomimetic shark skin structure pattern for engineering applications, we conducted the elastic hydrodynamic lubrication analysis for the shark skin surface pattern. The shark skin surfaces with roughness are generated numerically in the similar size with real shark skin scales. For the spherical contact on the generated shark skin surface with two different flow directions which are transversal and longitudinal, 3-dimensional elasto-hydrodynamic lubraction analysis are carried out. The result of the longitudinal flow which are similar with the flow of shark skin shows more beneficial effects with lower pressure and less sensitive effect with surface roughness.