Study Of Large Scale Swath Strength Analysis And Tranverse Section Optimization

Small Waterplane Area Twin Hull(SWATH)is developed in the 1970 s and this development's main purpose is to improve ship's seakeeping.As engineers begin to realize the excellent performance of SWATH,it has a development trend towards to the large scale.Thus,it needs to pay special attention to the structure for higher requirements.More research should be done in SWATH structural optimization.Based on CCS Guidelines of Small Waterplane Area Twin Hull Craft,this paper uses software Patran/Nastran to calculate stress of different area under different Loading conditions,then select the main control condition.In addition,this paper also studies the area easy to lead high stress and analyses the reason and give some solution of it.Based on variable density method topology optimization,this paper propose a new kind of haunch frame structure design according to the selected high stress area.This new design can effectively improve the structure stiffness and reduce stress level.Finally,based on the initial design and large scale SWATH structural sensitivity analysis,the paper optimize the size of main structure.Under the criterion of guidelines,effectively reduce the total weight of the hull structure.The thesis puts forward a new set of large scale SWATH structural optimization,including the choice of control Loading condition,topology of main structure and structural size optimization.