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

  • 제41권5호
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  • Pages.337-343
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  • 2017
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  • 1226-4873(pISSN)
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  • 2288-5226(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
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다이캐스팅 보의 등가 기공결함을 고려한 강도평가

Strength Estimation of Die Cast Beams Considering Equivalent Porous Defects

  • 박문식 (한남대학교 기계공학과)
  • 투고 : 2016.02.15
  • 심사 : 2016.12.28
  • 발행 : 2017.05.01
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초록

각종 기공과 같은 결함을 허용하는 다이캐스팅 부품의 강도를 현장 수준에서 평가할 수 있는 이론적 방법을 제안한다. 결함을 갖는 부재의 탄성시험을 통해 강성도를 구하고 이를 결함이 없는 이론적 강성도와 비교함으로써 등가 기공률을 산출한다. 등가 기공률 식은 Eshelby의 함유이론으로부터 유도하였다. 산출된 등가 기공률은 Mori-Tanaka 법을 이용하여 기공결함을 포함하는 재료의 응력-변형률 선도를 그리기 위하여 사용된다. 본 연구에서는 Hollomon 변형경화 모델을 사용하였다. 이 응력-변형률 선도를 이용하면 균일분포의 기공결함을 갖는 다이캐스팅 부재의 강도를 평가할 수 있게 된다. 등가 기공률을 고려한 하나의 이론해로서 직사각형 단면의 다이캐스팅 보에 대한 삼점 굽힘의 탄소성 강도를 소성힌지의 방법으로 유도하였다.

As a shop practice, a strength estimation method for die cast parts is suggested, in which various defects such as pores can be allowed. The equivalent porosity is evaluated by combining the stiffness data from a simple elastic test at the part level during the shop practice and the theoretical stiffness data, which are defect free. A porosity equation is derived from Eshelby's inclusion theory. Then, using the Mori-Tanaka method, the porosity value is used to draw a stress-strain curve for the porous material. In this paper, the Hollomon equation is used to capture the strain hardening effect. This stress-strain curve can be used to estimate the strength of a die cast part with porous defects. An elastoplastic theoretical solution is derived for the three-point bending of a die cast beam by using the plastic hinge method as a reference solution for a part with porous defects.

키워드

참고문헌

  1. NADCA, 2015, NADCA Product Specification Standards for Die Castings, North American Die Casting Association, Illinois, pp. 3-1-3-46.
  2. IAI, 2009, Global Aluminium Recycling: A Cornerstone of Sustainable Development, International Aluminium Institute, London, pp. 1-36.
  3. Kaufman, J. G. and Rooy, E. L., 2004, Aluminum Alloy Castings: Properties, Processes and Applications, ASM International, Ohio, pp. 39-54.
  4. Totten, G. E., Funatani, K. and Xie, L., 2004, Handbook of Metallurgical Process Design, Marcel Dekker, Inc., New York, pp. 368-370.
  5. Major, J., 1998, "Porosity Control and Fatigue Behavior in A356-T61 Aluminum Alloy," Transactions-American Foundrymens Society, pp. 901-906.
  6. Avalle, M., Belingardi, G., Cavatorta, M. P. and Doglione, R., 2002, "Casting Defects and Fatigue Strength of a Die Cast Aluminium Alloy: a Comparison Between Standard Specimens and Production Components," International Journal of Fatigue, Vol. 24, No. 1, pp. 1-9. https://doi.org/10.1016/S0142-1123(01)00112-8
  7. Kuwazuru, O., Murata, Y., Hangai, Y., Utsunomiya, T., Kitahara, S. and Yoshikawa, N., 2008, "X-ray CT Inspection for Porosities and its Effect on Fatigue of Die Cast Aluminium Alloy," Journal of Solid Mechanics and Materials Engineering, Vol. 2, No. 9, pp. 1220-1231. https://doi.org/10.1299/jmmp.2.1220
  8. Zhao, H. D., Wang, F., Li, Y. Y. and Xia, W., 2009, "Experimental and Numerical Analysis of Gas Entrapment Defects in Plate ADC12 Die Castings," Journal of Materials Processing Technology, Vol. 209, No. 9, pp. 4537-4542. https://doi.org/10.1016/j.jmatprotec.2008.10.028
  9. Irfan, M. A., Schwam, D., Karve, A. and Ryder, R., 2012, "Porosity Reduction and Mechanical Properties Improvement in Die Cast Engine Blocks," Materials Science and Engineering: A, Vol. 535, pp. 108-114. https://doi.org/10.1016/j.msea.2011.12.049
  10. Aziz Ahamed, A. K. M. and Kato, H., 2014, "Influence of Casting Defects on Tensile Propertiesof ADC12 Aluminum Alloy Die-Castings," Materials Transactions, Vol. 49, No. 7, pp. 1621-1628. https://doi.org/10.2320/matertrans.F-MRA2008814
  11. Eshelby, J. D., 1957, "The Determination of the Elastic Field of an Ellipsoidal Inclusion and Related Problems," Proceedings of the Royal Society A, Vol. 241, No. 1226, pp. 376-396. https://doi.org/10.1098/rspa.1957.0133
  12. Mori, T. and Tanaka, K., 1973, "Average Stress in the Matrix and Average Elastic Energy of Materials with Misfitting Inclusions," Acta Metallurgica, Vol. 21, pp. 571-574. https://doi.org/10.1016/0001-6160(73)90064-3
  13. Park, M. S., 2014, "An Enhanced Mean Field Material Model Incorporating Dislocation Strengthening for Particle Reinforced Metal Matrix Composites," Journal of Mechanical Science and Technology, Vol. 28, No. 7, pp. 2587-2594. https://doi.org/10.1007/s12206-014-0615-3
  14. Weng, G., 1990, "The Overall Elastoplastic Stress-strain Relations of Dual-phase Metals," Journal of the Mechanics and Physics of Solids, Vol. 38, No. 3, pp. 419-441. https://doi.org/10.1016/0022-5096(90)90007-Q
  15. Federico, S., 2010, "On the Linear Elasticity of Porous Materials," International Journal of Mechanical Sciences, Vol. 52, No. 2, pp. 175-182. https://doi.org/10.1016/j.ijmecsci.2009.09.006
  16. Kwon, Y. and Park, M. S., 2013, "Versatile Micromechanics Model for Multiscale Analysis of Composite Structures," Applied Composite Materials, Vol. 20, pp. 673-692. https://doi.org/10.1007/s10443-012-9292-5
  17. Yu, T. X. and Zhang, L. C., 1996, Plastic Bending: Theory and Applications, World Scientific Publishing Co., Singapore, pp. 7-50.