Oil & gas
The White Rose Field Development
Subsea Production System (SPS), located approximately
350 km off the east coast of Newfoundland, will be
developed using subsea wells tied back to a Floating/Production/
Storage/Offloading (FPSO) Vessel. The subsea wells
are connected to the FPSO via flexible risers. Each
riser passes through an I-Tube, I-Tube Extension,
Bend Stiffener Connector and Bend Stiffener. The Bend
Stiffener Connectors are complex parts that must be
checked for acceptable maximum hot-spot stresses and
for desired minimum fatigue lives.
Martec Limited was contracted to review the four
existing Bend Stiffener Connector (BSC) designs to
ensure that they are structurally adequate. The BSCs
were checked for static strength and fatigue life,
using the finite element (FE) method to determine
detailed stresses. The specialized FE program HyperMesh
was used for pre and post-processing, and the general
purpose FE program ANSYS was used to analyse the BSC
models.
The bend stiffener assemblies are complex structures
where loads are transferred from the Bend Stiffener
to the BSC to the I-Tube Extension. The transfer of
these loads from one component to the next is through
a combination of interference fits and bolted connections,
a challenging scenario to model using FE. The FE model
developed by Martec included a section of the I-Tube
Extension and a representation of the Bend Stiffener.
The analysis identified a problem high-stress area
in one of the BSC designs. The design was modified
and re-evaluated. Subsequently, all four BSC designs
were found acceptable for static strength and fatigue
considerations.
|
