Life-cycle cost (LCC) based design procedure to determine the optimal design parameters and target reliability under nonlinear deformation for marine installations

ABSTRACT

This study proposes a procedure to determine the optimal design parameters and target reliability based on Life cycle cost (LCC) based analysis. An iterative design procedure is performed for different levels of reserve strength ratio (RSR), and LCC is calculated. A case study is carried out for installation of the bottom fixed jacket support structure for offshore wind turbines (OWT) system subjected to extreme loading condition. To determine the ultimate capacity of the structure, static pushover analysis is integrated with the proposed design methodology. An evolutionary based particle swarm algorithm is selected for the structural design optimization of offshore jackets. The RSR evaluated from pushover analysis assists to determine the probability of failure based on the first order reliability method (FORM). Based on a set of LCC values, which are the collective sum of capital expenditure (CAPEX), operational cost (OPEX), and risk cost (RISKEX), the optimal design is reached.

KEYWORDS:

• Life-cycle cost
• reserve strength ratio
• reliability
• optimisation
• offshore wind turbine

Acknowledgement

The authors would like to thank Dr Tore Holmas of USFOS Company for his assistance with this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

M. Vishnu http://orcid.org/0000-0002-2097-7623