Structure Finite Element Analysis And Optimum Design Of Sandwich Composite Cabin

Advanced composite material has great prospects in shipbuilding industry sinceits light weight, corrosion resistance, and excellent mechanical properties. Currentlythe application of composite materials in large ships is still at preliminary stage farbehind foreign. Because of the anisotropy, analysis of composite materials is morecomplicated compared to conventional steel and isotropic materials. Designers usesandwich composite to make full use of its high strength lightweight features andimprove the stiffness of the structure. Meanwhile, designers need a deepunderstanding of composite mechanics and failure mechanisms.At present, ship design methods and mechanics theory has been more perfect,composite sandwich plate theory used in aircraft industry has been very mature.However, the study of sandwich composite used in shipbuilding industry is still in thepreliminary stage and mechanics theory of sandwich composite used on ships is in theinitial stage. Design theory needs to be improved. Using finite element method in shipstructure analysis can simulate the details of the ship. After discretization of the model,the stress and deformation of the structure can be obtained. By using the membrane,shell, bar, beam and other elements the main parts of the ship structure can besimulated.A structure analysis and design optimization of the composite sandwich platecabin on a large ship has been performed by appling ANSYS software in this thesis.Main contents and conclusions are as fellow：(1) Among the classical lamination theory, Reissener sandwich plate theory, Hoffsandwich plate theory, ⅡpycakoB-Du Qinghua sandwich theory, Hoff sandwichplate theory was chosen as the theoretical model.(2) Studied on the key technologies of modeling, such as the simulation methods ofsandwich panel, strengthening rib. Using APDL parametric programming andcommand to establish a model which was closer to the actual structure.Established the analytical method for the composite sandwich plate cabin base onthe ship industry related composite design standards, then analyzed the cabin structure under different loads.(3) Under the long-term load, the effect of the core material used in thestrengthening rib on the overall performance of the structure was analyzed. Theresults show that the skin of the strengthening rib was the main bearingcomponents, the effect of the core material on the overall performance of thestructure was very small. Under the short-term load, the strength of the variousparts of the structure meet the requirements. In cabin structure, stressconcentration mainly occurred at the intersection of the plates and ribs.(4) The cabin had a higher natural frequency which was different from eachexcitation frequency of the ship. Analysis of the opening on the right wall showedno stress concentration appeared in the opening area.(5) Checked the bolts in connection region of the cabin, grasped the bolts loaddistribution law. Optimized the distribution of the bolt according to thecalculation results. After optimization the number of the bolts was reduced fromthe initial378to133.Then analysis of the maximum bolt load area used the submodel technology. The results showed the strength of the plate meet therequirement.