Bend stiffener model with two node systems
A section of flexible pipe with bend stiffener is defined. The bend stiffener and the pipe have separate node systems and there is an initial gap between the pipe and the inside of the bend stiffener. The model is fixed in translatory motion at the end away from the bend stiffener. Rotation is applied in the oposite end, at the root of the bend stiffener.
The pipe is exposeed to
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tension
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internal pressure
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bending; applied by rotation of the bend stiffener
Model description
The model, see Figure 1, consists of thermal layers, carcass and zeta spiral that are specified based on the cross sectional area and with no detailed geometry. In addition to the crossection flexcross used to describe the pipe, an additional crossection is introduced to model the bend stiffener:
# name type node id od no_th rks imno_i imno_o
CROSSECTION MYBENDSTIFFENER NLBENDSTIFF 1 501 290 1096 10 0.1 matin matout
8 508 290 1096 10 0.1 matin matout
9 509 290 1096 10 0.1 matin matout
95 595 290 428 10 0.1 matin matout
101 601 290 428 10 0.1 matin matout
#
| When the bend stiffener is connected to a separate node system, the axial and torsional stiffness of the bend stiffener must be accounted for and type nlbendstiff must be applied (By selecting type nlbendstiff-bend, no axial and torsional stiffness is introduced from the bend stiffener, only bending stiffness is accounted for. This is typically applied when bend stiffener and pipe share the same node system.) |
To obtain contact between the pipe and bend stifener inside, contact elements must be defined:
ELCON bscontact cont130 bscontmat1 601 1 REPEAT 100 1 1
#
Elorient Coordinates 501 0 1e3 0
600 0 1e3 0
The properties of the contact are further defined in the contint and elprop sections:
# groupn mname sname is1 isn istx isty istz gt1 gt2 CONTINT bscontact nyecore bendstiffener 501 600 1000 10000 0.2 60 1 # # name type diameter inside ELPROP bscontact bellmouth 253.17 1
| The diameter used for contact is not based on the pipe diameter from the crossection definition of the pipe, but must be specified in the elprop of the contact element. |
Results
The curvature profile is obtained by glplot from bflex2010post, and shown at maximum displacement in Figure 2.
Relevant files
Processing of files from command line
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bflex2010 -n bflex2010_01
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bflex2010post -n bflex2010post_01