RIGID-PLASTIC APPROXIMATIONS FOR PREDICTING PLASTIC-DEFORMATION OF CYLINDRICAL-SHELLS SUBJECT TO DYNAMIC LOADING

A theoretical approach was developed for predicting the plastic deform ation of a cylindrical shell to asymmetric dynamic loads. The plastic deformation of the leading generator of the shell is found by solving for the transverse deflections of a rigid-plastic beam/string-on-found ation. The axial bending moment and tensile force in the beam/string a re equivalent to the are equivalent to the longitudinal bending moment s and membrane forces of the shell, while the plastic foundation force is equivalent to the shell circumferential bending moment and membran e resistances. Closed-form solutions for the transient and final defor mation profile of an impulsive loaded shell when it is in a ''string'' state were derived using the eigenfunction expansion method. These re sults were compared to DYNA 3D predictions. The analytical predictions of the transient shell and final centerline deflections were within 2 5% of the DYNA 3D results. (C) 1996 John Wiley & Sons, Inc.