Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Numerical Analysis of ]Residual Stresses and Birefringence in Injection/Compression Molded Center-gated Disks (I) - Modeling and Basic Results -

사출/압축 성형 Center-Gated 디스크에서의 잔류 응력과 복굴절의 수치 해석 (I) - 모델링 및 기본 결과 -

  • 이영복 (포항공과대학교 기계공학과) ;
  • 권태헌 (포항공과대학교 기계공학과) ;
  • 윤경환 (단국대학교 기계공학과)
  • Published : 2002.11.01
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Abstract

The present study has numerically predicted both the flow -induced and thermally-induced residual stresses and birefringence in injection o. injection/compression molded center -gated disks. Analysis system for entire molding process was developed based on an ap propriate physical modeling including a nonlinear viscoelastic fluid model, stress-optical law, a linear viscoelastic solid model, free volume theory for density relaxation phenomena and a photoviscoelasticity and so on. Part I presents physical modeling a nd typical numerical analysis results of residual stresses and birefringence in the injection molded center-gated disk. Thermal residual stress was found to be extensional near the center, compressive near the surface and tend to become toward tensional at the surface. A double-hump profile was obtained across the thickness in birefringence distribution: nonzero birefringence is found to be thermally induced, the outer peak is due to the shear flow and subsequent stress relaxation during the filling stage a nd the inner peak is due to the additional shear flow and stress relaxation during the packing stage. Predicted birefringence including both the flow -induced and thermally-induced one becomes quite similar to the experimental one.

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References

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