Structure Optimization Of Composite Hat-stiffened Panel

As composite material has the identity of high strength to density ratio and stiffness to ratio,anti-fatigue performance and designable characteristic,composite stiffened panel structures are widely used in the fuselage structures of modern aircrafts.Composite stiffened panel structures can withstand tension,compression and shear loads,its good global and local stiffness helps to reduce stress concentration and weakening effect of nail holes on cross-sectional area of the panel.So it has great advantage in saving weight.Consequently the research of the optimum design of composite stiffened panel is very important.The thesis is about designing composite stiffened panels of a hatch door.To solve the problem an optimum design method of composite stiffened panel was built up based on surrogate model.It can be applied to the structure and parameters optimization of hat stiffened panel structures under compression-shear load.The steps of this method are: the initial samples were firstly created by design of experiment(DOE),secondly the responses corresponding to the initial samples, including the weight and buckling factor,were computed by FEA,then the Kriging model was derived through the samples by iSIGHT.Finally the optimal solution was obtained with Genetic Algorithms (GA) and Sequential quadratic programming method (SQL) based on the Kriging model.High accuracy model that describes stiffened panel's real shape of the optimization result is built by FEA,by comparison their 1st order linear stability coefficients and weights are in accordance with each other.Therefore it proves that the whole strategy can satisfy the engineering requirements in accuracy.