DOI QR코드

DOI QR Code

Nonlinear Dynamic Analysis of Steel Lazy Wave Riser using Lumped Mass Line Model

집중질량 라인모델을 이용한 Steel Lazy Wave Riser의 비선형 동적 해석

  • Oh, Seunghoon (Korea Research Institute of Ships and Ocean Engineering) ;
  • Jung, Jae-Hwan (Korea Research Institute of Ships and Ocean Engineering) ;
  • Park, Byeongwon (Korea Research Institute of Ships and Ocean Engineering) ;
  • Kwon, Yong-Ju (Korea Research Institute of Ships and Ocean Engineering) ;
  • Jung, Dongho (Korea Research Institute of Ships and Ocean Engineering)
  • 오승훈 (한국해양과학기술원 부설 선박해양플랜트연구소) ;
  • 정재환 (한국해양과학기술원 부설 선박해양플랜트연구소) ;
  • 박병원 (한국해양과학기술원 부설 선박해양플랜트연구소) ;
  • 권용주 (한국해양과학기술원 부설 선박해양플랜트연구소) ;
  • 정동호 (한국해양과학기술원 부설 선박해양플랜트연구소)
  • Received : 2019.08.07
  • Accepted : 2019.10.16
  • Published : 2019.10.31

Abstract

In this study, the numerical code for the 3D nonlinear dynamic analysis of an SLWR (Steel Lazy Wave Riser) was developed using the lumped mass line model in a FORTRAN environment. Because the lumped mass line model is an explicit method, there is no matrix operation. Thus, the numerical algorithm is simple and fast. In the lumped mass line model, the equations of motion for the riser were derived by applying the various forces acting on each node of the line. The applied forces at the node of the riser consisted of the tension, shear force due to the bending moment, gravitational force, buoyancy force, riser/ground contact force, and hydrodynamic force based on the Morison equation. Time integration was carried out using a Runge-Kutta fourth-order method, which is known to be stable and accurate. To validate the accuracy of the developed numerical code, simulations using the commercial software OrcaFlex were carried out simultaneously and compared with the results of the developed numerical code. To understand the nonlinear dynamic characteristics of an SLWR, dynamic simulations of SLWRs excited at the hang-off point and of SLWRs in regular waves were carried out. From the results of these dynamic simulations, the displacements at the maximum bending moments at important points of the design, like the hang-off point, sagging point, hogging points, and touch-down point, were observed and analyzed.

Keywords

Lumped mass line model;Explicit method;Dynamic simulation;Numerical code;Steel lazy wave riser(SLWR)

Acknowledgement

Grant : 초심해역용 라이저(SLWR) 설계엔지니어링 핵심기술 개발

Supported by : 선박해양프랜트연구소