Numerical integration of Force and Velocity graphs to obtain energy.

[Ahmed.Arsalan]

Hello Respected Members!

I am presently working on Force Velocity integration to obtain energy of a falling hammer. I have attached two accelerometers and two strain guages to a rod, on which the hammer shall fall. I have attached the pictures which better explain the problems.
i m using Ni-cDaq 9172 and NI9237 ( accelerometers are piezoresistive) 

Please advise how to go about it.

[GerdW]

Hi Ahmed,

on the integration part:

Integration of discrete samples is just the sum of sample value * dt (sampling interval) in the simplest implementation. LabVIEW also provides functions to do the integration of waveform data…

On your triggering problem:

- You might set an analog start trigger in your DAQmx task when the hardware supports such triggers.

- You might analyze your data after sampling to find the triggers on your own. Most often it's a simple threshold limit of the signal, sometimes you can also use the derivation of the signal…

What have you tried so far?

Where are you stuck?

[Ahmed.Arsalan]

I have generated a graph which ideally should be for the force and velocity. but how to do the integration of both with respect to time. i am attaching a vi. 
please advise how to record these graphs into separate columns(arrays perhaps), which can later be used to plot a graph based on different energies in each hammer blow.

Kindly correct me if i have done the integration the right way.

i am attaching the formula as well..

[Dafrizzy]

Once you have data that appears to be correct, you could log that data to an Excel or TDMS file for post-analysis. Here is a good resource for getting started on TDMS/Excel logging: http://www.ni.com/newsletter/51339/en/

[GerdW · Accepted solution]

Hi Ahmed,

but how to do the integration of both with respect to time.

Right now you seem to have used the right ExpressVIs in the right order.

(I wouldn#t call this "programming", but just "configuring"…)

please advise how to record these graphs into separate columns(arrays perhaps), which can later be used to plot a graph based on different energies in each hammer blow.

There are more ExpressVIs, even ones for saving data to files…

[Ahmed.Arsalan · Accepted solution]

Thanks alot sir.

One last query is, how i can configure a software trigger on of the source , that is strain guage, and with that trigger , the accelerometer reading also starts, take 10k samples and auto stop.