INFLUENCE OF GEOMETRIC IMPERFECTIONS ON THE LOAD-CAPACITY OF ORTHOTROPIC STIFFENED AND COMPOSITE SHELLS OF REVOLUTION WITH ARBITRARY MERIDIANS AND BOUNDARY-CONDITIONS

A stiffness matrix for an element of a shell of I evolution has been derived, considering arbitrary load distributions and initial geometric imperfections. This element-stiffness matrix is based on the transfer-matrix method and describes the whole section of a shell of revolution between two rings in modal coordinates (a so-called super-element). The modal coordinates here are circumferential Fourier members, thus reducing the partial differential equations to ordinary ones. Several stability analyses investigating the sensitivity of composite shells to different geometric imperfection shapes were carried out. The influence of the load distribution and boundary conditions in combination with geometric imperfections was analysed by different modellings of a hypothetical Jupe Avant shell of the ARIANE 5 rocket.