• Title/Summary/Keyword: viscoelastic core

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A Study on Biomimetic Composite for Design of Artificial Hip Joint (인공 관절 설계를 위한 바이오미메틱 복합재료에 관한 연구)

  • 김명욱;윤재륜
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 1999.11a
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    • pp.234-238
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    • 1999
  • This study suggests the design of the functionally gradient composite, [0/90/0/core]$_s$ cross-ply laminate, to prevent stress concentration induced from the difference of rigidity between the bone and the artificial hip joint and to reinforce the wear property of the surface and the expectation of their mechanical properties. First, the four-point bending test is done about wet bones and dry bones to know the mechanical properties of the cortical bones. In result, the wet bone shows the viscoelastic behavior and the dry bone shows the elastic behavior. Moreover, we expect the properties of the proposed gradient composites as a function of carbon fiber volume fraction in each layer to apply Halpin-Tsai equation, CLPT(classical laminate plate theory), and Bernoulli beam theory etc. and decide the thickness ratio of each lamina in order to match Young's modulus of the anisotropic cortical bone with the proposed gradient composites.

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Numerical Modeling of Injection/Compression Molding for Center-gated Center-gated Disk (Part I) (Center-gated 디스크에 대한 사출/압축 성형공정의 수치적 모델링-압축성을 고려한 점탄성유체 모델의 사출성형-)

  • Kim, Ilhwan;Park, Seong-Jin;Chung, Seong-Taek;Kwon, Tai-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.2
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    • pp.289-301
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    • 1998
  • The present study attempted to numerically simulate the process in detail by developing an appropriate physical modeling and the corresponding numerical analysis for precision injection and injection/compression molding process of center-gated disk. In part I, a physical modeling and associated numerical analysis of injection molding with a compressible viscoelastic fluid model are presented. In the distribution of birefringence, the packing procedure results in the inner peaks in addition to the outer peaks near the mold surface, and values of the inner peaks increase with the packing time. Also, values of the density in the core region increase with the packing time. From the numerical results, we also found that birefringence becomes smaller as the melt temperature gets higher and that it is insignificantly affected by the flow rate and the mold temperature. As far as the density distribution is concerned, mold temperature affected the distribution of density especially near the wall. But it was not significantly affected by flow rate and melt temperature. Numerical results of birefringence coincided with experimental data qualitatively but didn't quantitatively.