Battery knowledge · Testing methods
Power spectral density
The way a random vibration profile is specified: acceleration intensity per unit frequency, in g²/Hz, across a band such as 5–200 Hz. The square root of the area under the curve gives the overall level in g rms. SAE J2380 and ISO 12405 use PSD profiles to stand for road vibration, whereas UN 38.3 uses a sine sweep.
- Abbreviation
- PSD
- Also called
- PSD vibration profile, random vibration, acceleration spectral density, ASD
- Unit
- g²/Hz
- Relationship
- g_rms = √(∫ PSD(f) df)
Example
Integrate a flat vibration band
An illustrative one-sided acceleration PSD of 0.01 g²/Hz from 10 to 110 Hz has area 1 g² and therefore 1 g RMS. A peak PSD value alone does not determine RMS without the bandwidth.
Explore the graph
A flat illustrative vibration band makes the integral easy to inspect.
Band width is 180 Hz. Variance = 1.8 g²; RMS acceleration = 1.342 g.
g_rms = √∫ PSD(f) df
Illustrative model. One-sided rectangular teaching spectrum. No resonances, random time history or standard-specific profile is generated.
Use in Lemonergy
Record specimen, state, instrument, temperature and timing.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- Battery Test Manual For Electric Vehicles, Revision 3
Jon P. Christopherson · Idaho National Laboratory · 2015
Topic background · Performance characterization, pulse resistance/power, life testing and reference performance tests; historical 2015 edition.