Structural Analysis And Improvement Design Of Frp Composite Yacht

With the development of modern material science,glass fiber reinforced composite(GFRP)is widely used in the shipbuilding industry,and have become the main material used in the construction of small and medium composite ships.It is of great significance to explore the ultimate bearing capacity,damage process and damage mechanism of FRP hull structure and local structure to ensure the safety and stability of composite ship structure.It is one of the future development directions of composite ship to seek a new type of ship structure which can not only ensure the reasonable and safe form of the ship structure,but also ensure the strength requirements of the ship structure.This thesis focus on the structural mechanics analysis of composite ship,reference for《Rules and Regulation for the Classification and Construction of Yacht(2012)》 and 《Rules of Construction and Classification and Construction of Sea-Going High Speed Craft(2015)》,first of all,the structure form and framework arrangement of FRP Yacht are designed,and the longitudinal bending moment,buoyancy and other loads are calculated by referring to the formula in the above rules.Then,the finite element simulation calculation method is used to numerically calculate the total longitudinal strength and part of the structural strength of the whole ship,and verify that the strength of the designed yacht structure meets the requirements of the rules.Finally,the finite element model is established by selecting the hat-stiffened panel in yacht,using Hashin damage criterion and material stiffness degradation to predict the damage initiation and expansion of FRP materials,and the Crushing foam constitutive model is used as the damage failure criterion of foam materials.The progressive failure analysis method of hat-stiffened panel under bending and axial load is carried out to predict the damage type,damage propagation and ultimate load.According to the characteristic of non-uniform beam,by changing the height of uniform section hat-stiffened,and improving the structure of uniform section hat-stiffened panel,9 groups of non-uniform section hat-stiffened with different height ratio are designed.Using the progressive damage analysis method was used to calculate 9 groups of non-uniform section hat-stiffened panel with different height ratios.Through the comparative analysis of data,the height ratio size with better ultimate bearing capacity of non-uniform section hat-stiffened panel is selected from 9 groups,under the premise of ensuring that the cross-sectional areas of the end section and the middle section of non-uniform section hat-stiffened are equal,by changing the height and width of the two sections,7 groups of non-uniform section hat-stiffened with different height-width ratios are designed.Using the progressive damage analysis method was used to calculate 7 groups of non-uniform section hat-stiffened panel with different height-width ratios.The result analysis shows that the bearing capacity of the non-uniform section hat-stiffened panel structure is better than that of the uniform section hat-stiffened panel structure,the influence of height ratio and height width ratio on the structural performance and damage evolution of non-uniform section hat-stiffened panel are also obtained.The improved design of uniform section hat-stiffened panel structure is realized,which provides a new type of hat-stiffened panel structure for the actual yacht production design and meets the engineering application requirements.