Nonlinear Collapse Analysis of Cylindrical Shells.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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This study was carried out to determine the effects of plasticity and cutouts on the buckling of stiffened and nonstiffened cylindrical shells. Axial and end moment loading configurations were considered. The problem was investigated using the nonlinear and linear branches of the STAGS Structural Analysis of General Shells computer code. It becomes clear through this study that cutouts positioned within cylindrical shells create results that are not easily predictable using past shell experiences. The moment field in a nonlinear analysis has a much greater effect on a more flexible structure than a less flexible one. This characteristic is not present in a linear analysis due to the removal of the higher order rotation terms that effect strain. An elasticplastic analysis appears to precipitate collapse in much the same manner as do cutouts. The collapse results obtained using a completely nonlinear plastic analysis can be closely approximated using Gerards plasticity equation. To prevent warping of the end plane under bending two rings separated by a distance determined by the parallel axis theorem are needed to counteract the lack of rotational rigidity in the shell. Author