Combined Compression-Torsion Buckling Tests of Laminated Composite Cylindrical Shells

Results are described for six composite test cylinders constructed of either four or six plies of graphite-epox y or boron-epoxy and subjected to combined torsion and compressive loading. All the shells were 15 in. in diam and 15 in. long. The stacking sequence effects exhibited by these thin laminates produced significantly different buckling capacities depending on the direction of torque application. A test technique was developed to define the entire range of torsion/compr ession ratios for each type of shell, and one specimen was used to define each shell type. The interaction between the torsion-compression buckling stresses was shown to be linear except at high percentages of compression stress.