On the monitor, a peak spiked. "18 Hertz," Sarah whispered. "There it is."
Most tests use sinusoidal frequencies (typically 4 Hz to 33 Hz for general components) to simulate the steady-state vibrations of a running engine or propeller. mil std 167 2 pdf
Three months prior, the Vanguard project had been in trouble. During sea trials, the prototype motor had developed a harmonic resonance at 22 Hertz. It wasn’t a loud noise—it was a low, thrumming vibration that traveled through the hull and turned the water around the sub into a beacon for enemy sonar. In the silent service, vibration was death. On the monitor, a peak spiked
Testing under MIL-STD-167-2 is rigorous and aims to reveal structural weaknesses before a ship leaves the dock. On the monitor