Mooring Cost Optimization via Harmony Search

Abstract

A mooring system optimization program has been developed to minimize the cost of offshore mooring systems. The paper describes an application of the optimization program constructed based on recently developed harmony search optimization algorithm to offshore mooring design which requires significant number of design cycles. The objective of the anchor leg system design is to minimize the mooring cost with feasible solutions that satisfy all the design constraints. The harmony search algorithm is adopted from a jazz improvisation process to find solutions with the optimal cost. This mooring optimization model was integrated with a frequency-domain global motion analysis program to assess both cost and design constraints of the mooring system. As a case study, a single point mooring system design of an FPSO in deepwater was considered. It was found that optimized design parameters obtained by the harmony search model were feasible solutions with the optimized cost. The results show that the harmony search based mooring optimization model can be used to find feasible mooring systems of offshore platforms with the optimal cost.

Music Inspired Algorithms

“…• Structure design optimization (Geem et al 2005b;Geem and Hwangbo 2006;Degertekin 2008Fesanghary et al , 2012Kaveh and Talataha 2009;Kaveh and Abadi 2010;Hasançebi et al 2010;Khajehzadeh et al 2011;Bekdas ß and Nigdeli 2011;Erdal et al 2011;Lagaros and Papadrakakis 2012;Kaveh and Ahangaran 2012;Shahrouzi and Sazjini 2012;Miguel and Miguel 2012;Lee and Geem 2004;Ryu et al 2007;Lee et al 2011). …”

Various continuous harmony search algorithms for web-based hydrologic parameter optimisation

“…In order to overcome this imperfect structure, researchers have improved the original discrete HS algorithm to handle continuous-type variables (Lee and Geem, 2005;Mahdavi et al, 2007) and applied to various continuous-variable problems, such as heat and power economic utilisation (Vasebi et al, 2007), offshore oil structure mooring (Ryu et al, 2007), aquifer parameter and structure determination (Ayvaz, 2007) and soil stability analysis (Cheng et al, 2008). However, this continuous-variable HS algorithm is also expected to be applied to hydrologic parameter calibration problems.…”

Mooring Optimization in Time Domain Using Harmony Search

“…HS has certain advantages over gradient-based methods: initial values for decision variables are not needed and because a stochastic random search is adopted, derivative information is unnecessary. Differences between this new methodology and previous mooring optimization approaches [7,8,[12][13][14] are: 1) a focus on step-wise analysis of mooring design whereby unfeasible and duplicate designs are filtered out; 2) implementation of 3 design criteria with the help of penalty functions: 3) a focus on optimizing on horizontal turret loading in time domain. The methodology is presented and discussed in section 2 and applied to the design of a mooring system for a large FPSO in section 3.…”

“…Harmony search (HS) is a phenomenon-mimicking algorithm inspired by the improvisation process of musicians [6]. The algorithm has been successfully applied in the offshore industry for mooring optimization [7,8] as well as in the IT, energy and medical sectors [10]. Advantages of HS over other meta-heuristic algorithms [6,9] are that fewer mathematical requirements are imposed and that it can easily be adopted for various types of engineering optimization problems.…”