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Fig. 29 from the 1997 modejump paper. This slide shows edge-on "snapshots" of the post-buckled PANEL I (PANDA2 mode-jumping constraint turned off during optimization cycles) taken at six times (time in seconds) during the STAGS transient phase of the overall nonlinear analysis.
During this transient phase the load factor PA is held constant: PA = 0.7013, just above the load level at which STAGS fails to converge to a nonlinear static equilibrium state during the first phase of the complete STAGS analysis.
The transient behavior is characterized primarily by the postbuckling waves in the panel skin sliding to and fro along the axis of the blade-stiffened panel.
Each of the six frames (a-f) shown here corresponds to a peak value of the dynamic hoop stress shown in the next slide.
Note that near the beginning of the transient STAGS analysis there are approximately 8 axial half-waves, and near the end of the transient phase there are approximately 10 axial half-waves. This is mode jumping.
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