Buckling of Externally Pressurized Composite Torispherical Domes

Abstract

The results of external pressure buckling tests on 0.25 m diameter woven composite (mainly CFRP) domes are given in the paper and they are compared with the predictions of the shell buckling program BOSOR 4. The agreement between theory and experiment was satisfactory. The tests also show that the buckling strength of CFRP torispheres is good. They could replace steel torispheres and would be considerably lighter. The buckling pressures of the woven composite domes are a function of the Young modulus E but the relation is not a simple linear one (the in-plane shear modulus G₁₂ also needs to be taken into account). Results of some tests on CFRP and GFRP domes lend support to this statement. The provisions of BS 4994, when applied to these domes, predict that buckling is the controlling failure mode. While this is correct, the buckling pressures predicted by BS 4994 seem rather low. The effect of dome thickness on the buckling pressures was expected to vary as (t/R)². This was confirmed herein, to a limited extent, by a few tests on shallow CFRP domes.