A complete description of these procedures is given in Dynamic Stress/Displacement Analysis.
- Steady-state dynamics
This procedure calculates the amplitude and phase of the structure's response caused by harmonic excitation over a user-specified range of frequencies. Typical examples include the following:
The response of car engine mounts over a range of engine operating speeds.
Rotating machinery in buildings.
Components on aircraft engines.
- Response spectrum
This procedure provides an estimate of the peak response (displacement, stress, etc.) when a structure is subjected to dynamic motion of its fixed points. The motion of the fixed points is known as “base motion”; an example is a seismic event causing ground motion. Typically the method is used when an estimate of the peak response is required for design purposes.
- Random response
This procedure predicts the response of a system subjected to random continuous excitation. The excitation is expressed in a statistical sense using a power spectral density function. Examples of random response analysis include the following:
The response of an airplane to turbulence.
The response of a structure to noise, such as that emitted by a jet engine.