Structural analysis and design of geodesically stiffened composite panels with variable stiffener distribution

摘要

A computationally efficient analysis is developed to predict the critical buckling loads of a geodesically stiffened composite panel under in-plane loading. The analysis procedure accounts for the contribution of the in-plane extensional and out-of-plane bending stiffness of the stiffeners through the use of the Lagrange multipliers technique in an energy method solution. The analysis is used to understand the effect of various stiffener deformation modes on the buckling load and to determine skin deformation patterns of geodesically stiffened panels under various load combinations. The analysis routines are then coupled with the numerical optimizer ADS to create a package for the design of minimum-mass stiffened panels subject to constraints on buckling of the panel assembly and material strength failure. Material failure in the skin and stiffeners is estimated using a maximum strain criterion. The design variables that can be used for optimization include thickness of the skin laminate stiffness and height, and positions of straight stiffeners. Applied loads are uniaxial compression, pure shear, and combined compression-shear.