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Background:
I have a piezoelectric force transducer that I am using to measure the force produced by a combustion reaction in a tube. The issue is that there is a lot of ringing that occurs during the reaction, leading to oscillatory "noise" going back and forth about the x-axis when we expect to see more of a big force curve. I want to eliminate this noise so that we can get a more proper idea of the force being generated.

My understanding:
The combustion reaction on the transducer can be modeled as a mass-spring-damper system with a forcing function. The mass (the tube + reactants, known), the spring (the transducer, known stiffness), the damper (transducer?, damping ratio TBD), and the forcing function (combustion, unknown).
If I can get the transducer's response to an impulse, I can use that to obtain an approximate transfer function for the impulse response using MATLAB. From here, I believe I should be able to deconvolve the force data and the impulse response in order to get the input force from the transducer... I hope. Please point me in the right direction if I'm lost.

Question:
What is the best way to generate an impulse signal that I may use for this task?

What I've tried:
I've done drop tests with two screws of two masses directly onto the transducer, but the data seems kind of inconsistent between the screws. I took the drop test signals, filtered out HF noise, subtracted the means, zeroed out everything before time t=0, and then normalized them according to the max force recorded. Then I used an impulse as the input (at t=0, input=1; 0 elsewhere) and the signal itself as the output for MATLAB's tfest function.

Ben
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    Cross posted here: https://electronics.stackexchange.com/q/601537/152903 – Solar Mike Dec 23 '21 at 16:50
  • Thanks, wasn't sure if I was supposed to mention it. – Ben Dec 23 '21 at 17:11
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    Idea is to save people writing duplicates. – Solar Mike Dec 23 '21 at 17:12
  • It might be easier to generate ramps or sinusoids. Impacting the transducer directly sounds iffy, make sure you're not creating peak load past its rating. You could also try impacting tube walls. Also consider other effects resulting in ringing, like waves bouncing back and forth along the system's long dimension. – Pete W Dec 23 '21 at 18:37
  • could you provide rates on the combustion rate, the frequency rate and the high pass filter settings? – NMech Dec 24 '21 at 09:38
  • Are you sure that the"*ringing*" that was seen in the experiment is purely due to the transducer or if it is inherently present in the combustion reaction? If the oscillations are present in the combustion reaction, then why would you want to filter it away? Combustion reactions inside tubes can have acoustic / pressure oscillations. By attributing them to the transducer and filtering them away, we should not unintentionally mask/hide actual pressure oscillations generated during combustion. – AJN Dec 25 '21 at 04:21
  • We have high-speed footage of the combustion reaction occurring. Presumably, there'd be a visual indication if there were pressure oscillations. – Ben Dec 26 '21 at 05:09

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