Additional buckling solutions in PANDA2

David Bushnell, Hao Jiang, Norm Knight, Jr.
1999 40th Structures, Structural Dynamics, and Materials Conference and Exhibit   unpublished
Three new buckling models have been incorporated into PANDA2, a program for minimum weight design of stiffened composite panels and shells: 1. buckling of unstiffened panels or unstiffened portions of panels with use of double-trigonometric series expansions for buckling modal displacement components, u, u, w; 2. general buckling of cylindrical, stiffened panels with both rings and stringers treated as discrete beams; and 3. inter-ring buckling of cylindrical panels based on a discretized
more » ... a discretized single module model containing discretized ring segments and a discretized skin-smeared-stringer cylindrical surface to which the ring is attached. Examples are provided of buckling of certain isotropic and laminated composite flat and cylindrical unstiffened and stiffened panels and shells for which the predictions from the modified PANDA2, formerly unacceptably inaccurate, are compared with predictions from STAGS, a general-purpose finite element code. The new comparisons demonstrate that the modified PANDA2 is now well qualified for preliminary design in particular cases for which it previously yielded unreliable designs and designs that were overly conservative. The optimum design of a composite ring and stringer stiffened cylindrical shell derived by PANDA2 is evaluated with use of STAGS. The optimum design of an isotropic hydrostatically compressed internally T-ring stiffened cylindrical shell 'Fellow, AIAA;
doi:10.2514/6.1999-1233 fatcat:hetcecj4z5dxjgnucpxco3ppwm