Page 190 - Pipelines and Risers
P. 190
Trand Impact, Pullover and Hooking Loah 163
1.5
( 1 1.14)
and for Case 2:
( 6c:tint 1
Safety Factor = - (11.15)
Coating Effect on Steel Pipe Stiffness, ka
The coating effect on steel pipe stiffness, kz, may be established through finite element
analysis. However, this requires material stress-strain curves for the coating from the
manufacture. No information on the coating material properties is available for the
preparation of the present technical note. The coating effect on steel pipe stiffness is
conservatively neglected.
11.4.4 Trawl Board Stiffness, Mass and Hydrodynamic Added Mass
General
There are two masses associated with the trawl board:
- The Mass of the steel, m
- The hydrodynamic added mass, ma
It is assumed that:
- Steel Mass, m-3500 kg
- Added Mass, ma-2.14 m (STATOIL (1996)) for P-board
Trawl Board In-plane Stiffness Connected with Steel Mass
The mass of the steel, m, is connected to a spring which simulates the in-plane stiffness, ki, of
the board.
It is suggested by STATOIL (1996) that:
I
ki = 500 (MN m) (11.16)
Trawl Board Out-of-plane Stiffness Connected with Added Mass
The added mass, ma, is connected to a spring which simulates the bending stiffness, kb, of the
board.
It is suggested by STATOIL (1996) that:
