Page 47 - Pipelines and Risers
P. 47
20 Chapter I
- free-span VIV (Vortex Induced Vibrations)
- trawl pullover and hooking response
The in-place modules further include FEM (deterministic) and reliability (probabilistic)
models. Typical reliability design is:
- calibration of safety factors used in the estimation of the appropriate cover height required
to prevent upheaval buckling,
- probabilistic modeling of hydrodynamic loads and soils friction for on-bottom stability
design.
The local strength modules provide tools for limit-state design to predict pipeline strength
under the following failure modes @ai and Damsleth (1997)):
- local buckling,
- bursting,
- ratcheting,
- material non-homogeneity,
- fracture and fatigue based on damage mechanics models,
- trawl impacts and dropped objects.
The local strength modules also include deterministic models and probabilistic models.
Typical probabilistic models are reliability-based strength criteria, in which safety factors are
calibrated using structural reliability.
The Simulator provides:
1. A through-life design approach to the pipeline model and predicted behavior.
2. Application and refinement of finite element techniques to model the behavior of
pipelines in the marine environment.
3. Through life monitoring and re-assessment of pipelines in operation.
The Simulator development benefits from the experience gained in the design, development
and application of the first generation engineering methodologies plus advances in PC-based
computing power and software development environments.
Advanced general-purpose finite element programs (ABAQUS and ANSYS) have been
applied in the practical design of pipelines as described below:
