Im very new in labview and I would like to try to do a simple impact test using lab view.
I want to get the dynamic stiffness as my results. I have facing some confusion as below:
1) At first, I have connect an accelerometer and a impact hammer to the analog input.
I get the time signal for both accelerometer and impact hammer. I try to convert the acceleration to displacement using double integration and then feed both of the signala into FRF(compliance). However, I found that the shape of the FRF produced is difference compared to the one I produced using the signal straight from accelerometer (without double integration). Suppose these two curve must be the same in shape and only difference in peak value.
I not really sure why this happen. Is any filter or configuration I have miss out?
2) I would like to get the dynamic stiffness which is the reciprocal results of the FRF(compliance). I am using the reciprocal function under mathematic. However, it can produce any results after I run the tests. Mean that the graph indicator is blank while the force and acceleration signals show the data.
I am not sure what is the correct way to get the reciprocal results of the FRF。 Can anyone show the example of wiring to me?
3) I would like to set some trigger for my excitation. Mean only the responses for the force above 0.3N will be capture together with the excitation force values to produce FRF. I have no idea on this trigger setting after go through the help section.
Thank you so much^^
