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This is Fig. 5 from the 1999 addsoln paper. Shown here are results from a rather unusual case in which the simple "straight-nodal-line" model displayed three slides ago is unacceptably unconservative.
This slide shows buckling of an axially compressed, square, composite, two-layered, angle-ply ([+ANG, -ANG]total), unstiffened flat plate.
The margin that reads, “buck(SAND)simp-support general buck; MIDLENGTH" (small squares) is computed from the PANDA-type (closed form) equation (57) in the 1987 PANDA paper (the straight-nodal-line model shown three slides ago and two slides ago).
The margin that reads, “buck(SAND)simp-support general buck; MIDLENGTH; (0.96*altsol)” (small circles) is computed from the much more elaborate double trigonometric series expansion alternate solution (“altsol”; see the previous slide) that can be used in executions of PANDA2 if the PANDA2 user so chooses. ("altsol" requires much more computer time than the simple PANDA-type model, and "altsol" is not needed in most practical cases.)
The trace with the small triangles is from STAGS, a general-purpose finite element computer program.
The discontinuity at ANG(1)=45 degrees from the simple PANDA-type straight-nodal-line model arises because of an abrupt change in the PANDA-type model from "a" to "b" as illustrated by the two sketches, a and b, shown three slides ago.
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