Measured free vibrations of partially clamped, square plates

Experiments were designed to measure the free, transverse vibrations for sq uare, thin elastic plates with two types of edge support configurations. On e configuration was fully clamped on three edges and free on the fourth edg e (CCCF), and the other was fully clamped on two adjacent edges and free on the other two edges (CCFF). For these respective configurations, up to 18 frequencies and the corresponding modal contours were measured using a scan ning laser-doppler velocimeter, acoustic excitation, and computer software. Measurements for the lowest five non-dimensional frequency parameters lamb da and their node lines compared favorably to the corresponding theoretical results available in the open literature. Curve veering may be the reason that several of the crisp modal contours at some higher excitation frequenc ies for the CCFF configuration were observed to be neither symmetric nor an tisymmetric about the plate's diagonal line of geometric symmetry. (C) 2000 Academic Press.