I am having an audio sample hitting an aluminium object (a small piece of hard ball 200g) at varying speed.

I am trying to calculate the amount of force the object is hitting with using the audio signal to find the amount of damage its causing to the aluminium

I am able to find any direct or indirect method to calculate that. I am not sure if its easy do it.

Any leads/directions?

  • $\begingroup$ One way to possibly narrow down techniques is to define inputs and outputs. Sounds like you have one input (audio signal) and two outputs (amount of force, amount of damage). Could you provide more details on these in your question? For example, how do you want to report amount of damage? Is there a "unit" of damage, or is it "high, medium, or low" based off the calculated force? $\endgroup$
    – Engineer
    May 23 '20 at 11:51
  • $\begingroup$ what hits the aluminium ball? Or is the aluminium ball hitting something? $\endgroup$ May 23 '20 at 17:24
  • $\begingroup$ It's a small hard ball like a leather balll hitting an aluminium plate. $\endgroup$
    – NitinG
    May 24 '20 at 12:05

Answer: Whenever the impact happens, that portion of audio has to be detected( if you want to automate it) or else you can identify those sections manually.

To automate it you need to identify characteristics of the audio during the impact, for ex: the frequency contents, or time spread. A good approach to combine these two characteristics is to either do a wavelet decomposition (morlet wavelet) or do a short time Fourier transform.

Once you have a method to identify these regions then you would need a reference (may be using an already available audio meter) to map these signals to audio (in DB), this would depend on how you quantize the analog audio, Sampling rate, FFT size etc. From this identified reference you can then map other audio impacts to suitable audio decibels.

  • $\begingroup$ I got a microphone and able to get all the peaks whenever the ball hits the aluminium plate. In parallel, I have some reliability analysis data from aluminium plate manufacturer which gives the data like if an object of 200g, coming at a speed of 100m/s, it will create x% of damage to the aluminium plate. Now I only need to relate audio frequency to the amount of force it can generate mathematically. $\endgroup$
    – NitinG
    May 24 '20 at 12:09
  • $\begingroup$ So with that reference data see which unique frequencies are active in the DFT and with what amplitude (using either STFT or wavelet as I explained), once you have this established simply map the amplitude of those frequencies to decibels /damage based on reference data, ex: reference data produced peaks at 10Hz with apmiltide 5, and damage is x, then if you model damage as a linear function of magnitude of impact then another impact with magnitude 10 at 20Hz will map to 2x damage, it depends on how you model and interpret the Fourier domain $\endgroup$ May 24 '20 at 12:15
  • $\begingroup$ Try and derive the model from the reference data $\endgroup$ May 24 '20 at 12:18

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