Study On Strength Assessment Method For Typical Bearing Structure Of Cruise Superstructure

Cruise is a tourist ship sailing in the ocean.Its typical feature is the tall and plump superstructure.Due to the high construction threshold,the construction of large cruise ships is mainly concentrated in European and American shipyards.Compared with traditional ships,the superstructure of large cruise ships is huge,and its functional requirements are more complex and diverse than those of ordinary ships.The design of typical superstructure will be a big difficulty.Because of the blockade of related technology of cruises abroad and the lack of experience in design and construction of large cruise in China,the development and progress of the cruise industry in China are seriously restricted.Therefore,it is imperative to carry out research on key technology of structural design of large cruise.Typical structures of large cruise superstructure are thin plate,densely perforated stiffened high panels and so on.Compared with traditional ship structure design,traditional strength assessment methods have some limitations in evaluating large cruise superstructure.Therefore,it is urgent to establish a set of strength assessment methods for typical bearing structures of large cruise superstructure.Taking the typical load-bearing structure of large cruise superstructure as the object of study,this paper combines numerical simulation with experimental verification.Based on the analysis of the overall structure and local structure design characteristics of cruise superstructure,the overall(local)strength evaluation method of large cruise superstructure deck frame and subsection are studied.Specific research work mainly includes the following aspects:(1)The overall-local structural characteristics of the superstructure of large cruise ships is analyzed.Through the analysis of the overall-local structural design of the existing superstructure of large cruise,the overall distribution and local design rules of the superstructure such as plate thickness,spacing,specifications,pillars and openings of the superstructure are obtained,and the objects and characteristics of the strength evaluation of the typical superstructure of large cruise ships are clarified.(2)The boundary condition,initial defect,calculation range of thin plates and stiffened high panels are analyzed.By comparing and analyzing various boundary conditions,different initial defect magnitudes and different calculation ranges,the influence rules of each factor on thin plate high web frame are obtained.(3)A series of influence analysis and discussion are carried out on the components and design variables of thin plates and stiffened high web,and the contribution degree of each factor to the ultimate longitudinal compression capacity is explored.The influence laws of deck thickness,the height and thickness of the longitudinal truss web,the longitudinal truss panel and thickness on the ultimate longitudinal compression capacity are obtained.(4)The influence analysis of web opening and its proportion of thin plates and stiffened high w are discussed.Through the numerical simulation of web openings,the influence rules of web openings on the ultimate stress of the frame under certain size of openings,small scale of openings and different layout of openings are obtained.(5)The semi-analytical formulas for the ultimate longitudinal compressive capacity of thin plates and stiffened high panels in a certain range of plate flexibility and web flexibility of longitudinal truss are obtained.The validity of the formulas is verified by the combination of plate model test and numerical simulation.The formulas are used to simplify the evaluation of the ultimate longitudinal compressive capacity of plate frames in a certain range of parameters.(6)The structural responses of typical decks and sections of superstructure under in-plane loads and total longitudinal loads are analyzed,and a preliminary idea for evaluating the overall-local structural strength of superstructure is established.The stress level and displacement distribution of the local model are similar to that of the whole model,and the boundary conditions are reasonably simplified,and the load combination is reasonable.Simplified loading can accurately evaluate the local structural strength and further reduce the difficulty of overall strength evaluation of superstructure.