Buckling Design and Analysis of a Payload Fairing 1/6th Cylindrical Arc-Segment Panel

Abstract

Design and analysis results are reported for a panel that is a 1/6 th arc-segment of a full 33-ft diameter cylindrical barrel section of a payload fairing structure. Six such panels could be used to construct the fairing barrel, and, as such, compression buckling testing of a 1/6 th arc-segment panel would serve as a validation test of the buckling analyses used to design the fairing panels. In this paper, linear and nonlinear buckling analyses have been performed using finite element software for 1/6 th arc-segment panels composed of aluminum honeycomb core with graphite/epoxy composite facesheets and an alternative fiber reinforced foam (FRF) composite sandwich design. The cross sections of both concepts were sized to represent realistic Space Launch Systems (SLS) Payload Fairing panels. Based on shell-based linear buckling analyses, smaller, more manageable buckling test panel dimensions were determined such that the panel would still be expected to buckle with a circumferential (as opposed to column-like) mode with significant separation between the first and second buckling modes. More detailed nonlinear buckling analyses were then conducted for honeycomb panels of various sizes using both Abaqus and ANSYS finite element codes, and for the smaller size panel, a solid-based finite element analysis was conducted. Finally, for the smaller size FRF panel, nonlinear buckling analysis was performed wherein geometric imperfections measured from an actual manufactured FRF were included. It was found that the measured imperfection did not significantly affect the panel's predicted buckling response.