TORSIONAL BUCKLING ANALYSIS AND DAMAGE TOLERANCE OF GRAPHITE-EPOXY SHAFTS

The measured torsional buckling load of Graphite/Epoxy shafts is found in good agreement with theoretical predictions based on a general shell theory that includes elastic coupling ffects and transverse shearing deformations. The direction of the applied torque and the lay-up stacking sequence drastically affects the buckling load (up to 80%). Transverse shearing deformations are found signficant when the number of circumferential waves in the buckling pattern is larger than 3. The residual strength of shafts with holes is also measured, and the dominant failure mode remains torsional buckling. The buckling mode patterns are seemingly unaffected by damage but buckling loads are lower compared to undamaged specimens.