CALCULATED NATURAL FREQUENCIES AND NORMAL MODES OF VIBRATION ON RANGE INSTRUMENTATION SHIP (T-AGM-19).
Acoustics and vibration lab. research and development rept.,
DAVID TAYLOR MODEL BASIN WASHINGTON D C
Pagination or Media Count:
Normal modes and natural frequencies of vibration were calculated for the hull of the Range Instrumentation Ship T-AGM-19, a T-2 tanker conversion for NASA. Nine vertical, six horizontal, six torsional, and five coupled torsion-horizontal modes and their natural frequencies are presented. Parameters used in the calculations by a digital computer and an electric analog computer are given. Calculations were performed for the ship in full load condition. The response of the hull to a sinusoidal vertical force acting at the stern was calculated using damping values of 0.01 mu omega and 0.03 mu omega ton-secsq ft. The effect of rotary inertia and shear, and flexural rigidity on natural frequencies of vertical and horizontal vibration was also calculated. Rotary inertia had very little effect on the frequencies. Shear and flexural rigidity had a large effect on the frequencies, particularly at frequencies above the first mode of vibration. Author