Optimal Design of Submarine Pipelines by a Genetic Algorithm with Embedded On-Bottom Stability Criteria

Abstract

This work describes a computational tool, based on an evolutionary algorithm, for the synthesis and optimization of submarine pipeline routes considering the incorporation of on-bottom stability criteria (OBS). This comprises a breakthrough in the traditional pipeline design methodology, where the definition of a route and the stability calculations had been performed independently: firstly, the route is defined according to geographical-topographical issues (including manual/visual inspection of seabed bathymetry and obstacles); afterwards, stability is verified, and mitigating procedures (such as ballast weight) are specified. This might require several design spirals until a final configuration is reached, or (most commonly) has led to excessive costs for the mitigation of instability problems. The optimization tool evaluates each candidate route by incorporating, as soft and hard constraints, several criteria usually considered in the manual design (pipeline length, bathymetry data, obstacles); also, with the incorporation of OBS criteria into the objective function, stability becomes an integral part of the optimization process, simultaneously handling minimization of length and cost of mitigating procedures. Case studies representative of actual applications are presented. The results show that OBS criteria significantly influences the best route, indicating that the tool can reduce the design time of a pipeline and minimize installation/operational costs.

An enhanced surrogate-assisted differential evolution for constrained optimization problems

“…The potential of the SADE-kNN-MCR+ method to solve such practical engineering problems is indicated by its performance in the Welded Beam and Pressure Vessel problems, which are also characterized by severely nonlinear constraint functions with diverse magnitudes. Thus, extensions of this work will incorporate this method into optimal design procedures for mooring systems, submarine pipelines and risers that have been considered in [1,3,60]. It is expected that the resulting procedures will lead to increased efficiency in terms of accuracy, computational costs, and more importantly to better engineering design solutions.…”

“…Of course, this would not be an issue for simpler cases where one knows a-priori the ranges of minimum and maximum violation values, and usual normalization procedures could be applied. However, for many real-world engineering applications such information is not available and cannot be estimated in advance[58,59,1,2,60].With MCR, all types of constraints are given the same priority and importance in the evaluation of each solution, irrespective of the range of their violation values.Algorithm 1: Pseudocode of the MCR CHTInitialize population of 𝑥 𝑖 individuals (𝑝𝑜𝑝𝑠𝑖𝑧𝑒); for 𝑖 = 1, 𝑝𝑜𝑝𝑠𝑖𝑧𝑒 do Evaluate objective function and constraints of each individual 𝑥 𝑖 ; end for each solution 𝑥 𝑖 do 𝑅 𝑁 𝑣𝑖 = ranking position of 𝑥 𝑖 according to its number of violations; for each constraint 𝑗 do 𝑅 𝜙𝑖 𝑗 += position of 𝑥 𝑖 in rank according to violation in constraint 𝑗; end if There are feasible individuals in the population then 𝑅 𝑓𝑖 = ranking position of 𝑥 𝑖 according to its objective function;…”

The Optimization of a Subsea Pipeline Installation Configuration Using a Genetic Algorithm

“…Subsea pipeline design is inextricably linked to and dependent upon subsea pipeline installation engineering. A series of studies have been conducted on the topic of subsea pipeline route optimization utilizing GA and the development of associated software tools-de Lima Jr. et al [23], Baioco et al [24], de Lucena et al [25] and Baioco et al [26].…”