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Forming of Dome and Inlet Parts of a High Pressure CNG Vessel by the Hot Spinning Process

열간 스피닝 공정을 통한 CNG 고압용기의 돔 및 입구 부 성형

  • Lee, Kwang O (Research Institute of Mechanical Technology, Pusan Nat'l Univ.) ;
  • Park, Gun Young (Research Institute of Mechanical Technology, Pusan Nat'l Univ.) ;
  • Kwak, Hyo Seo (Dept. of Mechanical Convergence Technology, Pusan Nat'l Univ.) ;
  • Kim, Chul (Research Institute of Mechanical Technology, Pusan Nat'l Univ.)
  • 이광오 (부산대학교 기계기술연구원) ;
  • 박건영 (부산대학교 기계기술연구원) ;
  • 곽효서 (부산대학교 기계융합기술학과) ;
  • 김철 (부산대학교 기계기술연구원)
  • Received : 2016.05.16
  • Accepted : 2016.07.04
  • Published : 2016.10.01

Abstract

The CNG pressure vessel is manufactured by a deep drawing and ironing (D.D.I) process for forming cylinder parts, followed by a spinning process for formation of the dome part. However, studies on the buckling phenomenon of the dome part and formation of the inlet part have not been performed yet, and the CNG pressure vessel is produced by the experience of the field engineers and the trial and error method. In this study, buckling phenomenon during the spinning process was predicted by comparing critical buckling loads obtained through theoretical analysis with axial loads from the FEA, and a method for preventing buckling of the dome part was proposed by employing commercial software (Forge NxT 1.0.2). Also, to form the inlet part, forming loads of the roller at contact point between the roller and the dome part were analyzed according to radii of the dome part, and the inlet part was formed by controlling the radius of the dome part.

압축천연가스(CNG) 압력용기는 D.D.I공정을 통해 실린더부를 제작한 후, 스피닝 공정을 통해 돔 부 성형이 이루어진다. 그러나 스피닝 공정의 입구 부 성형에 관한 연구는 미미하며, 현장 작업자들의 경험이나 시행착오에 의해 제작되고 있는 실정이다. 이에 본 연구에서는 이론 임계좌굴하중 및 유한요소해석에서 축 방향 하중의 비교를 통하여 좌굴발생을 예측하였고, 상용 소프트웨어를 이용하여 돔부의 좌굴 방지를 위한 방법을 제안하였다. 또한, 입구 부 성형을 위하여 돔 부와 롤러가 맞닿는 점에서의 돔부의 반경에 따른 롤러 하중을 분석하고, 이를 토대로 입구 부 성형을 수행하였다.

Keywords

References

  1. Kang, M. C., Lee, H. W. and Kim, C., 2011, "Optimal Design Considering Structural Efficiency of Compressed Natural Gas Fuel Storage Vessels for Automobiles," Transactions of Nonferrous Metals Society of China, Vol. 21, pp. 199-204. https://doi.org/10.1016/S1003-6326(11)61088-1
  2. Kim, C. H., Park, J. H., Kim, C. and Choi, J. C., 2004, "Expert System for Process Planning of Pressure Vessel Fabrication by Deep Drawing and Ironing," Journal of Materials Processing Technology Vol. 155-156, pp. 1465-1473. https://doi.org/10.1016/j.jmatprotec.2004.04.350
  3. Bae, J. H., Lee, H. W., Kim, M. S. and Kim, C., 2012, "Optimal Design for CNG Composite Vessel Using Coupled Model with Liner and Composite Layer," Journal of the Korean Society for Precision Engineering Vol. 29, No. 9, pp. 1012-1019. https://doi.org/10.7736/KSPE.2012.29.9.1012
  4. Kim, H., Bae, W., Jang, Y. and Kim, C., 2008, "Optimal Design of the Fuel Storage Vessel of CNG Automobile by Considering Structural Efficiency," Trans. Korean Soc. Mech. Eng. A, Vol. 32, No. 6, pp. 465-473. https://doi.org/10.3795/KSME-A.2008.32.6.465
  5. Kim, J.-H., Kim, E.-S. Kim, C. and Choi, J.-C., 2003, "Development of an Automated Design System of a Large Pressure using the Steel, 34CrMo4," Journal of Korean Society of Precision Engineering, Vol. 20, No. 8, pp. 21-29.
  6. Bae, J. H., Lee, H. W., Kim, M. S. and Kim, C., 2013 "Optimal Process Planning of CNG Pressure Vessel by Ensuring Reliability and Improving Die Life," Trans. Korean Soc. Mech. Eng. A, Vol. 37, No.7, pp. 865-873. https://doi.org/10.3795/KSME-A.2013.37.7.865
  7. Lee, H. W., Jung, S. Y. and Kim, C., 2013, "Study of Hot Spinning Process for Head of CNG Storage Vessel," Trans. Korean Soc. Mech. Eng. A, Vol. 37, No. 4, pp. 547-554. https://doi.org/10.3795/KSME-A.2013.37.4.547
  8. Zoghi, H. and Sayeaftabi, M., 2013, "Enhanced Finite Element Analysis of Material Deformation and Strain Distribution in Spinning of 42CrMo Steel Tubes at Elevated Temperature," Materials & Design, Vol. 47, pp. 234-242. https://doi.org/10.1016/j.matdes.2012.11.049
  9. Zoghi, H., Arezoodar, A. F. and Sayeaftabi, M., 2012, "Effect of Feed and Roller Contact Start Point on Strain and Residual Stress Distribution in Dome Forming of Steel Tube by Spinning at an Elevated Temperature," Journal of ENGINEERING MANUFACTURE, Vol. 226, No. 11, pp. 1880-1890. https://doi.org/10.1177/0954405412461325
  10. Akkus, N. and Kawahara, M., 2006, "An Experimental and Analytical Study on Dome Forming of Seamless Al Tube by Spinning Process," Journal of Materials Processing Technology, Vol. 173, No. 2, pp. 145-150. https://doi.org/10.1016/j.jmatprotec.2005.11.011
  11. Gere, J. M. and Goodno, B., 2011, Mechanics of materials 7th, McGraw-Hill, NewYork.