Study On The Fracture Strength Characteristic Of Hull

Ship and ocean structures usually have damage imperfections undercomplicated loads condition, such as corrosion crack. Cracks can not onlycause the reduction of hull effective section area, but also destroy theintegrity and symmetry of hull structure. The structural members aroundthe damage area would lose support and greatly weakened the hullcarrying capacity, resulting in crack propagation and hull fracture.The rupture of the ship can directly lead to catastrophic consequences.In order to ensure the safety and vitality of ship, effectively evaluating theultimate bearing capacity and fracture mechanics characteristics of hullunder different typical kinds of initial imperfection (cracks) and complexload are needed. Therefore, the main contents of the present paper includeas follows:(1)Firstly, mainly discusses the theory of crack propagation criterionsand numerical simulation of crack propagation methods based on theprevious studies. Combining the “element deletion” method based on“failure strain” criterion with finite element software MSC.Dytran to analysis the crack development, deformation characteristics and ultimatebearing capacity of structure under external load condition.(2) Secondly, using MSC.Patran to establish finite element models tostudy on crack propagation rules, distortion characteristics, stress-straindistribution and bearing capacity with different crack location, crack lengthand combination cracks. The aim of this chapter is to improve the carryingcapacity, especially after the ultimate load by means of optimizing theprofile form and arranging longitudinal box girder.(3) According to container ship which has the large opening, doublebottoms and double sides characteristics, simplified finite element modelwas established by MSC.Patran. Initial crack was arranged in theappropriate position combined with experience for the study of fracturemechanics characteristic of the hull structure and the effective crackprevention measures.