DOI QR코드

DOI QR Code

Reliability-based Flaw Assessment of a Mooring Chain Using FORM and SORM

FORM 및 SORM을 이용한 무어링 체인의 신뢰성 기반 결함평가

  • Lee, Choong-Hyun (Department of Naval Architecture and Ocean Engineering, College of Engineering, INHA University) ;
  • Kim, Yooil (Department of Naval Architecture and Ocean Engineering, College of Engineering, INHA University)
  • 이충현 (인하대학교 공과대학 조선해양공학과) ;
  • 김유일 (인하대학교 공과대학 조선해양공학과)
  • Received : 2017.03.10
  • Accepted : 2017.09.20
  • Published : 2017.10.20

Abstract

This study presents the reliability-based flaw assessment for the crack in the mooring chain of a floating type offshore structure. BSI(British Standard Institution) flaw assessment procedure BS7910 was combined with first- and second-order reliability method (FORM, SORM) so that the acceptance of a given flaw can be assessed considering the uncertainties of parameters that play important role in the flaw assessment. Considering the probabilistic nature of the crack size and long-term distribution of the stresses acting on the crack in mooring chain, the failure probability was calculated using FORM and SORM. To check the validity of the FORM and SORM, Monte Carlo simulation was also carried out to derive the true limit state function and compared with the results of FORM and SORM.

Keywords

References

  1. Almarnaess, A., 1985. Fatigue handbook: Offshore steel structures, Chapter 10: Fatigue life calculation. TAPIR: United States.
  2. American Petroleum Institute (API), 2007. Fitness-for-service, API 579e1/ASME FFS-1.
  3. British Standard Institution (BSI), 2013. Guide to methods for assessing the acceptability of flaws in metallic structure, BS 7910.
  4. Fiessler, B. Rackwitz, R. & Neumann, H. J., 1979. Quadratic limit states in structural reliability. Journal of the Engineering Mechanics Division, 105(4), pp.661-676.
  5. Hohenbichler, M. Gollwitzer, S. Kruse, W. & Rackwitz, R., 1987. New light on first-and second-order reliability methods. Structural Safety, 4(4), pp.267-284. https://doi.org/10.1016/0167-4730(87)90002-6
  6. Lee, O.S. Kim, D.H., 2007. Reliability of fatigue damaged structure using FORM, SORM and fatigue model. Proceedings of the World Congress on Engineering, pp.1322-1328.
  7. Lie, H. 1992. Simplified fatigue analysis of mooring lines. Posisjoneringsmotet '92; 7-9.october, Fagernes.
  8. Kang, B.J. Kim, J.H. Kim, Y., 2016. Engineering criticality analysis on an offshore structure using the first- and second-order reliability method. International Journal of Naval Architecture and Ocean Engineering, 8(6), pp.577-588. https://doi.org/10.1016/j.ijnaoe.2016.05.014
  9. Kang, B.J. Kim, Y.I. Ryu, C.H. Park, S.G. Oh, Y.T., 2014. Development of a flaw assessment software using the fracture mechanics approach. The Annual Autumn Conference, SNAK, Changwon, 6-7 November, 2014. pp. 675-680.
  10. Metropolis, N. & Ulam, S., (1949). The Monte Carlo method. Journal of the American Statistical Association, 44(247), pp.335-341. https://doi.org/10.1080/01621459.1949.10483310
  11. Mohammad, H. S., 2015. Fatigue analysis and design of mooring systems. assessment and comparison of different methods. Master's thesis, Norwegian University of Science and Technology.
  12. Rackwitz, R. & Flessler, B., 1978. Structural reliability under combined random load sequences. Computers & Structures, 9(5), pp.489-494. https://doi.org/10.1016/0045-7949(78)90046-9
  13. Yu, Z. Zheng, Z. Qunpeng, Z., 2012. Improved reliability analysis method based on the failure assessment diagram. Chinese Journal of Mechanical Engineering, 25(4), pp.832-837. https://doi.org/10.3901/CJME.2012.04.832