Optimization Design Of Hose And Mooring Chain Of CALM System Based On Genetic Algorithm

Catenary anchor leg mooring(CALM)single point mooring system can be applied to tankers with different displacements in both deep and swallow water,as well as in different marine environments.Besides,it’s easy to be built.As a result,it’s widely used in marine oil and gas exploration.Analysis on dynamics and strength for CALM single point mooring system of Chinese lantern type will be carried on in the paper.And key parameters will be optimized.The main work is as follows.Based on Morison equation and the finite element method(FEM),a coupling numerical model for buoys,the mooring system and underwater hose is established.Static and dynamic response analysis under operating condition and surviving condition is carried out to study the time-domain motion response of the whole system,as well as the effect of slow drift and motion characteristics at key points.Effects of different original positions for the buoyancy material,spacing and other parameters on the maximum tension of the anchor chain and the hose,as well as on the motion performance of buoys are analyzed.Aiming at multi-objective optimization for structures like hoses and the anchor chain in CALM single-point system,the genetic algorithm was well studied.And the influence of different establishment methods for the objective function on the optimization results was analyzed.Thus the Pareto optimal solution set was found in a given solution space.At the same time,the study of fitness function and of mutation method is carried out to ensure the diversity of the optimal solution.Finally,an automatic optimization framework of CALM single-point mooring system based on genetic algorithm is established,and a multi-objective optimization program is developed.Sensitivity analysis research for the main design parameters such as the mooring-cable length,anchoring radius,anchor angle,and hose length is carried out.And the optimization design of mooring system configuration is carried out for the minimum effective tension of the anchor chain and the maximum bending radius of the hose.The optimization process based on the genetic algorithm is convergent,and the optimal solution can be finally got.Based on the relevant regulations,critical components such as underwater hoses,the mooring cable and the anchor chain are checked.The results show that the optimized CALM single-point mooring system has better motion and strength performance,and that its main structure is optimally configured,which meets the requirements of the project specification.That is of great value for the design and analysis of the mooring system.