Peak-hold equivalent amplitude for transient vibration

In summary, the conversation discusses the use of peak-hold equivalent amplitude in processing transient vibration data, as opposed to linear averaging. The question is raised about converting the data into the correct units, and the suggestion is made to consult a textbook or online resources for guidance. It is also mentioned that PSD may not have been used in the processing, and the peaks of the transient vibration were captured and held instead of being averaged. The peaks are said to match closely, but there may be some data manipulation involved.
  • #1
CmRock314
5
0
I have a question regarding transient vibration data I received that was processed into a peak-hold equivalent amplitude (units = g). I have come across peak-hold before which is a type of "averaging" that retains the highest values from each estimate in random vibration overlap processing and FFT frequency 'bins' as opposed to linear averaging. Understandably, peak-hold is used in transient vibration as the vibration is changing in frequency content over time as opposed to stationary random vibration.

I have processed the same set of data into random vibration using linear and peak-hold averaging. The peak-hold (envelope) PSD is lower than the peak-hold equivalent amplitude processed by someone else. It doesn't surprise me since my peak-hold PSD is expressed in units of G^2/Hz and the peak-hold equivalent amplitude is expressed in G. My question is, how does one convert this transient vibration into the correct units of peak-hold equivalent amplitude?

I have never come across this before. I thought it may be as simple as multiplying by the delta-frequency and taking the square root, but this doesn't appear to come out the same.
 
  • #3
CmRock314 said:
...I thought it may be as simple as multiplying by the delta-frequency and taking the square root...

Well I would just keep trying different things and figure it out on my own. Otherwise I would just find a textbook or something (I found a lot of PDFs when I googled it)
 
  • #4
TheQuietOne said:
Well I would just keep trying different things and figure it out on my own. Otherwise I would just find a textbook or something (I found a lot of PDFs when I googled it)
I appreciate the thoughts. I have found a lot of information. One of the things I ended up discovering is PSD was not actually used. It was simply just an FFT of a transient sine vibration that used multiple overlaps (90%) to capture the peaks of the transient; the peaks from each estimate are 'held' (i.e. peak hold) as opposed to averaging. My answer is still not matching exactly, but I'm thinking some data manipulation to the time history may have taken place. The important part is the peaks are matching up quite closely, but the other I'm comparing to has a little more dynamic range.
 

What is peak-hold equivalent amplitude for transient vibration?

Peak-hold equivalent amplitude for transient vibration is a measurement used in vibration analysis to determine the maximum amplitude of a transient vibration event. It is calculated by taking the maximum value of the vibration signal over a specified time period.

Why is peak-hold equivalent amplitude important in vibration analysis?

Peak-hold equivalent amplitude is important because it provides a single value that represents the severity of a transient vibration event. This allows for easier comparison and evaluation of different vibration events.

How is peak-hold equivalent amplitude different from peak amplitude?

Peak amplitude is the highest value of a vibration signal at any point in time, while peak-hold equivalent amplitude is the highest value over a specified time period. Peak-hold equivalent amplitude takes into account the duration of the vibration event, providing a more accurate representation of its severity.

What factors can affect the peak-hold equivalent amplitude for transient vibration?

The peak-hold equivalent amplitude can be affected by various factors such as the type of vibration (sine, random, shock), the frequency and amplitude of the vibration, and the duration of the event. It can also be influenced by the location and orientation of the sensor used to measure the vibration.

How is peak-hold equivalent amplitude used in practical applications?

Peak-hold equivalent amplitude is commonly used in the design and evaluation of structures and equipment to ensure they can withstand transient vibrations. It is also used in predictive maintenance programs to monitor the health of machinery and identify potential issues before they become critical.

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