For the rigid frame shown, a motor is located on the horizontal member at its center. The motor imparts a driving frequency of 2000 rpm (33.4 Hz) to the structure. Determine the first 3 natural frequencies and animate the associated modes of vibration on your computer. Is this driving frequency acceptable? Then run a structural dynamics analysis using F(t) shown. Use E = 29 × 106 psi, A = 60 in2, I3 = 500 in4, S3 = 100 in3, (t = 0.001 s, α = 3.00, and β = 0.001.

Figure P16-17

5000 Ib 3 240 in. (3) -240 in.- FO) Ib 5000 - t, s 0.25