Buckling Analysis And Stacking Sequence Optimization Design Of Composite Conical Stiffened Cabin

The inter-stage cabin is a typical structure used to connect different stages on a launch vehicle.This paper takes the minimum weight as the goal,the strength and stability of the structure as constraints,uses the blending model and combines genetic algorithm and finite element software to optimize the layup sequence of the composite stiffened cabin.The main research work and results include:(1)The linear and nonlinear buckling analysis of composite tapered laminated shells is carried out,and the influence of cone apex angle and aspect ratio on the buckling load and bearing capacity of the structure is clarified.The results of buckling analysis show that keeping the aspect ratio constant and reducing the cone angle,the buckling load of the composite tapered laminated shell gradually decreases.There is a maximum point between the cone angle of 0° and 36.9°,which maximizes the linear buckling load after mass weighting.(2)The effects of the matching of different stiffness of the skin and the ribs,the crosssection size of the ribs and the interface debonding on the axial compression buckling load of the tapered stiffened shell are analyzed.It is found that composite stiffened shells with different stiffness matching have different buckling modes.When the skin(ribs)is less rigid than the ribs(skin),the buckling mode appears as local buckling of the skin(ribs),and the final nonlinear critical buckling load is greater than the linear buckling load.However,when the stiffness of the skin and the ribs are equal,the buckling mode appears as the overall buckling of the stiffened shell,and the nonlinear buckling load is less than the linear buckling load.(3)The blending model based on regional sequence is developed,which can effectively ensure that the sequence of adjacent regions in the optimization process always meets the fiber continuity requirements.Using genetic algorithm as the optimization algorithm and Nastran as the structural solver,the optimization program and data interface program are compiled.The optimization results show that the algorithm converges fast,and the optimization scheme satisfies the structural strength,stability constraints,and fiber continuity process constraints.