No actual structure is a perfectly rigid body - all structures vibrate by flexing and twisting. The response of structures to random vibrations can be quite complicated because they vibrate with complex deformations and have more than one resonant frequency. The compliance curve, the classic method of measuring dynamic rigidity, is a useful tool for evaluating the basic dynamics of a vibrating structure. The curve supplies information on the two key parameters that govern dynamic performance - minimum resonant frequency and maximum amplification at resonance, which can be used to calculate the actual relative motion between two points on the structure’s surface.

No actual structure is a perfectly rigid body - all structures vibrate by flexing and twisting. The response of structures to random vibrations can be quite complicated because they vibrate with complex deformations and have more than one resonant frequency. The compliance curve, the classic method of measuring dynamic rigidity, is a useful tool for evaluating the basic dynamics of a vibrating structure. The curve supplies information on the two key parameters that govern dynamic performance - minimum resonant frequency and maximum amplification at resonance, which can be used to calculate the actual relative motion between two points on the structure’s surface.