Geometrical parameters of a cross-stiffened flat rectangular plate.
Experimental arrangement with a doubly curved cross-stiffened panel. White dashed lines on the panel face show the positions of the hidden stiffeners on the rear side.
Point mobility of the curved stiffened panel. Solid line, analytical result; dashed line, experimental result.
Transfer mobility of the curved stiffened panel. Solid line, analytical result; dashed line, experimental result. The upper figure is the transfer mobility at point 1 in a plate field (see Fig. 2 ); the middle figure is at point 2 on a stiffener; the lower figure is at point 3 at the crossing of two stiffeners.
Mode shape of mode (2, 1) obtained from experiment.
Mode shape evaluation. The left-hand figures show the mode shapes in the x direction, while the right-hand figures are the mode shapes in the y direction. The corresponding mode numbers are shown to the left. Solid lines represent the theoretically determined mode shapes; the circles represent the experimentally determined mode shapes; and the dashed lines show the neutral positions of the curved base plate.
(Color online) Geometries of four panel models. The upper models from left to right have a curvature radius R x of 2.0, 1.0, and 0.6 m, respectively, while the lower model has a radius of R x = 0.2 m.
Deviations of predicted natural frequencies for panels with different curvatures of radii of R x . Natural frequencies obtained with the smearing technique (f analytical) are compared with calculated results from the FE analysis (f FE), which is considered as the reference. The deviation is calculated as 100*(f analytical − f FE)/f FE. The left-hand figure shows results for modes (2, 1) and (3, 1), while the right-hand figure is for modes (1, 2), (2, 2), and (3, 2).
Two-dimensional mode shape of mode (2, 2) obtained by the FE analysis for the panel with a curvature radius of R x = 0.2 m and R y = 1.5 m.
Predicted and measured natural frequencies for the experimental panel model. The deviation for each mode is calculated as the difference between the analytical natural frequency (f analytical) and the experimental data (f Ex). Thus, the deviations are calculated as 100*(f analytical − f Ex)/f Ex.
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