Stability Analysis (Buckling Strength) Of Members In Resistance Damage Structures Under Torsion

Structural buckling strength (structural stability) is an important branch of structural strength analysis, and it is a complex subject. But it is significant to guarantee structural safe. With the development science, there are more and more high strength material coming forth. So structural stability is much more important than material strength.There are two aspects to be considered about structural stability. They are longitudinal ultimate strength and lateral torsion buckling. The first one is determined by deck and bottom structural and the second one is produced by bending moment acting on side shell railing. Ultimate strength is the most important in ship structural research, and there are the most people to research it. Because it relate to the overall vitality. Its content is mainly about anti-bending of longitudinal. Side shell railing may be buckle because of over vertical pressure transverse loads and transverse loads.The latter is less important but it should be considered to satisfy the strength demand of ship structural.Exact and credible methods are needed for saving material under safe environment,at the same time these methods must make full use of material. In another word,buckling stress should be advanced to close to material yield stress.Then material can be used in the best way.This paper researched structural stability of stiffeners in deck. And it also considered the influence of torsion. The result have been compared with many ways such as structural method of thin hull, FEM method and experience formulae. This paper also analyse the buckling of side shell railing under lateral pressures.Finally buckling critical stress of stiffeners were evaluated by considering the buckling influence under lateral pressures.A question, which is worried by experts, is how to improve ship's vitality. Then scholars have put forward some plans for it such as ulterior design and blocking design and so on. Experts also have given a new plan to improve ship's strength. For example Germanic frigate numbered 123 be strengthened with trunk girders. This structure can protect ship from damage by weapon. This trunk structure can also protect cables. 123 frigate can resist missile of 150 kilograms, but other frigate can only resist missile of 50 kilograms.This subject mainly research mend plan of adding trunk girders in active warship. The result compared the ultimate torsion moment with the one without improving and also analyzed effect of trunk girders to improve vitality of warship.