Research On Strength Direct Calculation Method For The Whole Structure Of Large Crane Ship

With the development of various large-scale engineering construction at sea,floating crane as the indispensable equipment in engineering supporting service facilities has developed gradually in the direction of large-scale and specialization,and its structure strength has got the attention of the professionals.Large floating crane has a special structure and working condition and the whole ship loading condition is also relatively complex.To get all kinds of structure deformation and stress accuratly in dangerous working conditions,cargo hold structure strength direct caculation already can't meet the requirements,so it is more reasonable to do the whole structural strength direct calculation for the floating crane.However,the cost of manpower,time and resources needed for whole structure direct calculation is much larger than cargo hold calculation.In the country,there are still not many research on this aspect.A set of relatively complete calculation method has not yet formed in specification in this area.So we need to do further research on the method of whole structural strength direct calculation for the large crane,and we need more further research on some key problems of whole ship structural strength direct calculation process.This paper explores and discusses the key methods in the process of whole ship structural strength direct calculation,such as the establishment of whole ship structure finite element model,static load applied,wave load short-term and long-term forecasting,load balance adjustment,calculation and applied of inertial load,boundary conditions and so on and gets a set of ship structural strength direct calculation methods and processes according to the relevant specification to modify load calculation formula.And taking a certain type of bulk carrier as an example,this article respectively uses displacement constraints and inertial release two kinds of boundary conditions in the direct calculation to discuss the suitability of inertial release in the whole structure direct calculation based on two calculation results of two kinds methods which support each other.A 3000 t large floating crane ship is taken as a research subject.The structural strength direct calculation of target ship includes applying static load and predicting wave load short-term and long-term forecast based on the equivalent design wave method according to the treatment method of key problems that this article puts forward,choosing appropriate boundary constraint method after the whole ship loading dynamic balance adjustment,getting the deformation and stress distribution of the whole ship structure based on the stress state of every load case and finally evaluating the main structures in accordance with the relevant strength standard.The whole ship finite element analysis process proves the rationality of whole ship structure direct calculation method put forward in this paper.The research work in this paper has certain guiding significance for whole structure direct calculation of the most ship types and it provides certain technical experience and accumulation for improving the theoretical system of whole ship structure strength direct calculation method.