Studies on the Failure of Stiffened Cylindrical Shells Subjected to Dynamic Loads.
Final rept. 1 Jan-31 Dec 77,
FLORIDA UNIV EGLIN AFB GRADUATE ENGINEERING CENTER
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The major objective of this study was to investigate the effects of axial stiffening of cylindrical shells subject to transverse blast loadings. Two existing methods for predicting dynamic response of cylindrical shells were modified to include axial stiffening. A semi-analytical energy method was chosen as a first cut design predictor and tables of normalized deflection versus external energy imparted to the structure are presented. In addition a more detailed analytical energy method was modified to include axial stiffening. In both cases the stiffeners were introduced by simply adding terms to the kinetic and potential energy terms of the basic shell equations rather than introducing membrane-bending coupling by use of more complicated anisotropic constitutive relations. The primary results of both methods indicate that the effect of axially stiffening a cylindrical shell using stiffeners typical of those in aerospace applications is very small. Both methods have been incorporated into computer algorithms which allow an investigator to determine failure modes of blast loaded shells either by an engineering approach or a more sophisticated detailed approach. Author