Structure Reliability Research Of FRP Catamaran Under Wave Loading

With the plan and development of water tourism and the implementation of the project construction in China,domestic yacht industry is developing fast,this promoted the study of advanced yacht structure.Yacht structure reliability can reflect the structure safety status objectively,which is one of the most important direction of ship structure research.To improve the reliability of the yacht and reduce the structure weight is the important symbol of the yacht industry development.In this paper,we take a FRP passenger ship as the example,make reliability research under wave loading with the finite element technology,the main content of the paper includes:(1)The stress analysis of the FRP catamaran hull.Set up the hydrodynamic model and the structure calculation model of 24 m catamaran,get the hydrodynamic pressure in six degrees of freedom movement through frequency domain Hydrodynamic analysis.transfer the wave loading forecasting results to the load input of structure analysis,calculate the hull stress under three kinds of extreme conditions.The result shows when under the largest lateral bending moment,The biggest stress reach 45.542 MPa and is at the joint of left hull and head of the cross structure.(2)Reliability calculation of the hull based on JC.Set up reliability calculation model of the FRP catamaran according to reliability theory,calculate the structure reliability of the hull under3 extreme conditions with JC.The calculation shows the reliability are higher than security requirement,the maximum lateral bending moment condition is the most dangerous,its minimum reliability is 4.86 and appear in the area which hull is connected to the transverse bulkhead.(3)Lightweight study of the catamaran hull based based on reliability.Transfer the target reliability index into levels consistent with the safety factor.With the safety factor and lightweight as the target,we use response surface optimization method and by changing the thickness of the FRP catamaran hulls to make catamaran reliability and lightweight calculation,Summarize the flow of our calculation.The result shows that the lightweight effect gets to 33.2% compared to traditional design when meeting reliability safety and standard requirement.(4)The reliability calculation and application effectiveness analysis of FRP catamaran lightweight.According to the previous flow of reliability and lightweight calculation,We takeanother 15 m FRP catamaran as the example,and make reliability and lightweight calculation for it.The result shows that compared with the traditional design,make lightweight calculation when meeting the reliability of hulls,the lightweight effect of the FRP catamaran is obvious,the reduction of weight gets to 16.1%.The reliability and lightweight method has practical and promotion significance for lightweight structure design of FRP catamaran.