Research On Strength And Fatigue Life Of Bolted Joint In FRP Ship

Fiber Reinforced Plastics(FRP) ship has been widely used in ship building industry, with its great advantages of high specific strength, stable structure and wind-resistant performance. Mechanical joint is widely used in the structure of FRP ship, as the main kind of mechanical joint. However, mechanical joint makes a large stress concentration, which leads to fatigue damage easily; anisotropy, brittleness and heterogeneity make the mechanical connection failure more complicated.Based on mechanics of composite materials, damage mechanics, fatigue test and damage research, the paper combines the composite material application background of mechanical connection structure on the ship with Ansys, a finite element software. By using of the APDL language, the paper writes a program in order to calculate the composite materials laminated plate damage with a round hole, and the fatigue life. On this basis of the program, the cumulative damage and ultimate strength of the composite materials and the fatigue damage of various joint form of mechanical connection and are analyzed. Finally, the intensity and fatigue damage of mechanical connection in a ship mast are analyzed, which provides a reference for the mechanical connection fatigue damage research.Firstly, based on mechanics of composite materials, damage mechanics and the fatigue theory, fatigue damage model of FRP laminate structure is established. The model uses Hashin failure criteria and the gradually dropped material performance model, which can be generally used in the FRP laminate structure. The model can be used to complete the simulation process of the composite materials a with round hole and calculate the composite materials laminated plate damage and life. By using of the model, the composite materials laminated plate damage with a round hole is analyzed, the factors such as temperature, humidity, hole spacing are discussed, which leads to the objective laws of factors impacting material ultimate strength.In the following, in terms of different forms of mechanical connection structure, the fatigue damage of single lap joints and double lap joints, the static strength, fatigue life and damage development rule are analyzed. At last the influence of fatigue damage compared with different layer is discussed.Finally, the fatigue damage of mechanical connection in a ship mast is studied. At first, stress and strain analysis of ship mast under the wind load is completed, the load of the mast is simplified. Then the static strength analysis of the hast is studied compared with the hast without sandwich structure. At last, the fatigue damage and failure life of the ship mast are analyzed, the fatigue damage development form is studied. The results of the study provide a reference for the mechanical connection fatigue damage research.