Large amplitude when excitation frequency matches the natural frequency.
Resonance occurs when driving frequency is near a natural frequency: amplitude is limited only by damping, peak ≈1/(2ζ). Famous failures include the Tacoma Narrows Bridge. Avoid by detuning, adding damping or stiffening.
Soldiers break step on bridges to avoid exciting resonance.
Resonance can cause large vibration amplitudes from small forces, so engineers avoid it in machines, bridges and musical instruments.
Large amplitude when excitation frequency matches the natural frequency.
Resonance can cause large vibration amplitudes from small forces, so engineers avoid it in machines, bridges and musical instruments.
No. Tuned filters, musical instruments and radio receivers use resonance deliberately to amplify chosen frequencies.
Move the natural frequency away from the operating range, add damping, or change the stiffness and mass so the peak does not coincide with the forcing.
Typical applications include avoiding the resonance of a washing machine as it spins up, checking the bridge deck for a pedestrian crowd frequency and selecting a bearing and mount to avoid a critical speed range.
Study "Forced vibration" first (topic 76 of 106 in Engineering Mechanics). It covers the groundwork this topic builds on.
Campbell diagrams for machines. Q factor high for light damping. Crossing resonances quickly reduces response.
Soldiers break step on bridges to avoid exciting resonance.
The next topic is "Vibration isolation", which builds directly on this one.
It is classed as Advanced in Engineering Mechanics (topic 77 of 106). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Engineering Mechanics.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.