BOSOR5 can handle segmented and branched, elastic-plastic shells of revolution with discrete ring stiffeners, meridional discontinuities, and multi-material construction. BOSOR5 also includes creep. The shell wall can be made up of as many as six layers, each of which is a different nonlinear (elastic-plastic) material. In the pre-buckling analysis large-deflection axisymmetric behavior is presumed. Bifurcation buckling loads are computed corresponding to axisymmetric or non-axisymmetric buckling modes.

The strategy for solving the nonlinear pre-buckling problem is such that the user obtains reasonably accurate answers even if he or she uses very large load or time steps. This strategy is based on a sub-incremental iteration method in which the size of the sub-increment is automatically determined so that the change in stress is less than a certain prescribed percentage of the effective stress at each material point in the shell wall. Discrete rings of arbitrary cross section are considered to be assemblages of thin rectangular elements.

The input is interactive, as with BOSOR4 (BIGBOSOR4). BOSOR5 has been checked by means of numerous runs in which the results have been compared to other analyses and to tests. BOSOR5 does not supersede BOSOR4 or BIGBOSOR4 because it has no modal vibration capability, nor can it handle non-axisymmetrically loaded shells.

BOSOR5 graphic showing load-end-shortening curve

Graphic from Pressure Vessels and Piping: Design Technology – 1982, A Decade of Progress, S.Y. Zamrik and D. Dietrich, editors, published by ASME; Chapter 2.4 “Plastic Buckling” by David Bushnell, pp. 47-117.

Load-end-shortening curve with limit point A, bifurcation point B, and post-bifurcation equilibrium path, BD.

For a gallery of the kind of problem that can be solved by BOSOR5, see the slide show. This slide show is primarily composed of pictures taken from the long, illustrated abstracts of papers about BOSOR5 and results generated from executions of BOSOR5.

NOTE: BOSOR5 does NOT supersede BOSOR4 or BIGBOSOR4. BOSOR4/BIGBOSOR4 is restricted to the study of shells made of material that is linear elastic. BOSOR5 is more restricted than BOSOR4/BIGBOSOR4 in the type of analysis that BOSOR5 can do, but BOSOR5 will handle elastic-plastic material and creep.

Abstracts and Papers