Correlation Between Vibrations and Buckling of Cylindrical Shells Stiffened by Spot-Welded and Riveted Stringers

摘要

The Vibration Correlation Techniques (VCT) was successfully applied, as a nondestructive tool for definition of actual boundary conditions and better prediction of buckling loads, to shells with spot-welded and riveted stringer stiffeners. It was demonstrated that the effective boundary conditions of the shells are fairly well by this technique, and that the lumping effects of the initial imperfection in the definition of the equivalent restraints are relatively small. Measurements of initial geometrical imperfections were conducted prior to testing of each shell. It is shown that calculation of their degrading effect on the buckling load serves as a complementary tool for improved predictions of actual buckling loads. When combined with the more precisely defined boundary conditions, yielded by the VCT, the agreement between predictions and tests is significantly improved.