Bending, Ringing, Breaking and Flowing, Ch Vibrations of rods, beams and plates
Problem
One pane of a double-glazing unit is 4mm thick glass with E=70GPa, ν=0.22 and ρ=2500kgm−3. Taking the speed of sound in air as c=343ms−1, find the coincidence frequency fc=(c2/2π)ρh/D of this pane, where D=Eh3/[12(1−ν2)] is the flexural rigidity. State whether this pane's coincidence dip lies at a higher or lower pitch than the 2.0kHz dip of a 6mm pane of the same glass.