MEASURED FREE VIBRATIONS OF PARTIALLY CLAMPED, SQUARE PLATES

Experiments were designed to measure the free, transverse vibrations for square, thin elastic plates with two types of edge support configurations. One configuration was fully clamped on three edges and free on the fourth edge (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 scanning laser-doppler velocimeter, acoustic excitation, and computer software. Measurements for the lowest five non-dimensional frequency parameters λ 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 frequencies for the CCFF configuration were observed to be neither symmetric nor antisymmetric about the plateʹs diagonal line of geometric symmetry.