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A Study on Estimation of Fatigue Performance of Polyethylene Boat

폴리에틸렌 보트의 내구성 평가에 관한 연구

  • Oh, Jeong-Seok (Break-through Technology Center for Urban Wind Energy Systems, Kunsan National University) ;
  • Cho, Seok-Swoo (Department of Vehicle Engineering, Kangwon National University)
  • 오정석 (군산대학교 도시형풍력발전원천기술연구센터) ;
  • 조석수 (강원대학교 자동차공학과)
  • Received : 2013.11.25
  • Accepted : 2014.01.09
  • Published : 2014.01.31

Abstract

Endurance of ship hull can be estimated by existing regulations and fatigue estimation methods. These can be applied to the hull materials that are recommended by ship regulations but can't be applied to new materials. In this study, structural force in the worst sailing condition is obtained by the acceleration measurement test of small polyethylene boat and the endurance of small polyethylene hull is estimated by rainflow cycle counting method and linear cumulative damage rule. Maximum Von-Mises stress on the polyethylene boat is 1.8MPa and much lower than the fatigue strength of at least 5.9MPa for the fatigue life of $1{\times}10^9$ cycles. Fatigue life of the polyethylene boat hull is estimated to be 6,229 years.

선체 내구성은 기존 선급 규격에 의하여 구조 치수를 결정한 후 이러한 치수의 선체구조에 대하여 스펙트랄과 결정론적 및 간이 방법에 의하여 평가되고 있다. 이러한 방법은 선체재료를 선급 규격에서 제안하고 있는 재료로 구성하는 경우에는 적용할 수 있으나 선체 재료를 신소재로 구성하는 경우에는 적용할 수 없다. 따라서 본 연구에서는 폴리에틸렌 보트 선체에 대한 피로 손상을 평가하기 위하여 선체에 부하되는 단기간 선체 가속도를 직접 측정하고 이러한 데이터를 기초로 구조설계와 피로수명평가방법이 확립되지 못한 소형 선박의 선체 내구성을 선형누적손상 법칙으로 평가하는 방법을 제안하였다. 개발된 폴리에틸렌 보트의 경우 최대 가속도 상태에서 보트에 부하되는 최대 Von-Mises 응력은 1.8MPa로서 $1{\times}10^9$ 사이클 피로강도 5.9MPa 아래에 있고 유한피로수명개념을 적용한 폴리에틸렌 보트의 내구수명은 415년으로 평가되어져 거의 무한수명을 가지고 있다.

Keywords

References

  1. J. D. Kim, "Fatigue Assessment of Ship Structures : Recent State of the Art", Journal of KWJS, Vol.16, No.5, pp. 1-10, October, 1998.
  2. J. S. Park and J. Y. Ko, "Estimation about Local Strength using FE-Analysis for Steel Yacht", Journal of KSMES, Vol.11, No.2, pp.77-82, December, 2005.
  3. I. S. Nho, J. K. Kim and J. H. Yoo, "Fatigue Strength Assessment of a Ship Structures using the Influence Coefficient Concept and Spectral Analysis Technique", Journal of SNAK, Vol.34, No.2, pp.75-84, May, 1997.
  4. D. S. Um, S. W. Kang, S. G. Lee and W. B. Kim,"A Study on the Fatigue Strength Analysis of the Welded Joints in Ship Hull Construction", Journal of KWJS, Vol.10, No.4, pp. 259-267, December, 1992.
  5. Rhino, Rhino 3D 4.0 Manual, Rhino, 2010.
  6. S. S. Cho, "Study of Structural Design of Polyethylene Pleasure Boat", Trans. of Korean Soc. Mech. Eng. A, Vol.36, No.12, pp.1551-1561, December, 2012. DOI: http://dx.doi.org/10.3795/KSME-A.2012.36.12.1551
  7. ISO 12215-5, Small Craft-Hull Construction and Scantlings - Part 5 : Design Pressures for Monohulls, Design Stresses, Scantlings Determination, ISO, 2008.
  8. KS M 3022, "Testing Method for Tensile Creep of Plastics", KS, 2008.
  9. B. K. Hong, "A Study on the Standard of Ship Hull Construction for Aluminium Alloys Fishing Boats", The Korean Society for Fisheries and Marine Sciences Education, Vol.12, No.1, pp.22-82, January, 2000.
  10. KS B ISO 1143, Metals- Rotating Bar Bending Fatigue Testing, KS, 2008.
  11. R. E. Peterson, Stress Concentration Design Factors, P.75, Wiley & Sons Inc., New York, 1954.
  12. Y. H. Yeom, Material Test Method, Dong Myeong Press, Seoul, pp.243-248, 1989.
  13. ANSYS Workbench V12.1, ANSYS Workbench, V12.1, Fatigue Module Manual, ANSYS, 2010.
  14. J. A. Collins, Failure of Materials in Mechanical Design, John Wiley & Sons Inc., New York, pp.256-258, 1993.
  15. S. H. Baek, J. H. Jeon, K. Y. Lee, S. S. Cho and W. S. Joo, "Reliability Analysis and Preventive Maintenance for Fatigue Life of End Beam for Uncovered Freight Car", Trans. of Korean Soc. Mech. Eng. A, Vol.29, No.3, pp.495-502, March, 2005. DOI: http://dx.doi.org/10.3795/KSME-A.2005.29.3.495
  16. S. S. Cho, "A Experimental Estimation of Thermal Fatigue at Polyethylene Boat", Journal of KAIS, Vol.14, No.6, pp.2559-2565, June, 2013. DOI: http://dx.doi.org/10.5762/KAIS.2013.14.6.2559
  17. S. S. Cho, "A Study on Hull Form Development of Polyethylene Boat", Journal of KAIS, Vol.14, No.10, pp.4726-4732, October, 2013. DOI: http://dx.doi.org/10.5762/KAIS.2013.14.10.4726