Mechanical enables you to perform Frequency-Based Fatigue analyses using the Harmonic Response and Random Vibration analysis types or using a combination of the two.
- Random Vibration Analysis
When analyzing the dynamic response of the structure, the application uses the frequency domain for calculations and therefore loading is a function of frequency or random vibrations. Examples of this include:
Electronic vibration in PCB board
Automobile engine vibrations
Vibrations of a helicopter in flight
Vibrations of a shaker table
Natural vibrations of structures due to sea waves or winds
Refer to the Fatigue Material Properties for Random Vibration (Spectral) Fatigue and Fatigue Result Methods for Random Vibration (Spectral) Fatigue sections for additional technical details for Frequency-Based Fatigue calculations for Random Vibration analyses.
- Harmonic Response Analysis
If the response of the system is harmonic in nature, not random, the application uses the maximum stress response for a either a single target frequency or sweeping multiple target frequencies, along with the duration of exposure to calculate the fatigue effects. Refer to the Fatigue Result Methods for Harmonic Fatigue for additional information for Harmonic Fatigue analyses.
- Combination Analysis
You can also choose to calculate fatigue damage from Random Vibration and Harmonic analyses and then use the Fatigue Combination object to combine the effects in order to analyze the total damage to the system.