Buckling behaviour of FRP strengthened cylindrical metallic shells with initial geometric imperfections

Abstract

This paper investigates the buckling performance of FRP strengthened aluminium cylindrical airframe shells with initial geometric imperfections. This is studied for the shells with different r/t ratios undergoing different modes of buckling viz. elastic, transitional, and plastic. The difference in buckling response of FRP strengthened and corresponding bare metallic shells with variations in imperfection magnitude are brought out. This study demonstrates that 1) the elastically buckling shells display higher sensitivity to imperfection as compared to plastically buckling shells, and their buckling capacity and axial stiffness increase with FRP strengthening but decrease with increase in imperfection magnitude for both bare and FRP wrapped shells; 2) the transitional buckling shells display three distinct stages of buckling behavior with an increase in imperfection magnitude; and 3) higher number of FRP wraps stabilizes the metallic shell and leads to a uniform increase in buckling capacity at all values of imperfection.