am looking for any example vi's for impact/modal analysis testing. I am

[eldeebfox]

LAbview VI or C++ application in labview CVI

[joot]

Dear friends.

I am looking for any example vi's for impact/modal analysis testing, and animation of mode shapes. if any one knows please let me know.

regards

my mail ID : giridhar@mail.gtre.org

[Kurt_Veggeberg]

The Sound and Vibration Toolkit and Measurement Suite include examples for impact testing for both the Sound and Vibration Assistant and Sound and Vibration Toolkit.      You can try these on-line by going to : 

http://www.ni.com/trysv/    More details :  http://zone.ni.com/devzone/cda/epd/p/id/5635

This is the LabVIEW example in the Sound and Vibration Toolkit

svxmpl_impact_test_daqmx.vi

This is the project in the Sound and Vibration Assistant.

SVA_Impact Test(DAQmx).seproj

Within the operational modal analysis domain, there is a type of method that employs output-only system identification (or in other terms, time series analysis) techniques, namely, stochastic subspace identification (SSI). This type of method uses the output data of the system, which is here the sensor-measured data of the bridge, to identify a linear state-space model that best describes the observed output data. Then, in operational modal analysis context, the state transition matrix of the linear model is used to obtain the modal parameters.

The Advanced Signal Processing Toolkit provides the TSA Stochastic State-Space Modeling VI, which implements the SSI algorithm. Using this VI, the modal parameters can be computed with ease.

Kurt Veggeberg     Business Development Manager,  NI     kurt.veggeberg@ni.com

[pwb]

I am using svxmpl_impact_test_daqmx.vi, but get an error message:

Possible reason(s):

Measurements: Requested value is not a supported value for this property.

Valid Choices:  0.000000,  2.100000e-3

Property: AI.Excit.Val

Corresponding Value:  4.0e-3

Channel Name: Dev1/ai0

Task Name: _unnamedTask<3>

This looks like a problem with the current needed for the hammer force sensor, but I cannot see how to chnage any settings for this within the VI.

Any suggestions?

Also, why is there no choice for "force sensor" within labview for analogue inputs - why use ccelerometer for channel 0 ?

 

[dsb@NI]

Go to the DAQmx Create Channel VI in the Block Diagram of the example. Create a constant from the current excitation value input (yes, this input is connected to a terminal on the right side of the VI) and input a valid choice.

Also note, that this example is written to use hardware triggering on an analog edge. If your hardware does not support analog triggering, post back and I can supply a different LV example.

There is also an impact test example that ships with the Sound and Vibration Assistant. The Advanced work area supports software triggering as well as averaged Frequency Response.

IEPE force sensor channel is on the way!

Message Edited by dsb@NI on 01-04-2010 11:15 AM

[pktck]

Dear Doug

I have tried to use the example svxmpl_impact_test_daqmx.vi

But How do I connect to my iepe hammer and accelerometer which are connected to AI0, AI1 respectively to USB-4431 ?

I do not get any signals when I run the example. Pls Help.

[pwb]

Dear Doug

I have updated the VI I am using, uploaded here, to include a means of selecting the excitation source and current value, and to export to UFF58.

Now I get an new error message:

"Error -89121 occurred at Property Node DAQmx Timing (arg 1) in SVXMPL_Impact Test (DAQmx).vi


Possible reason(s):

Destination terminal to be routed could not be found on the device.

Make sure the terminal name is valid for the specified device. Refer to Measurement & Automation Explorer or your hardware documentation for valid terminal names.

Property: Ref.DigEdge.Src
Source Device: Dev1
Source Terminal: AnalogChannel
Channel Name: Dev1/ai0

Task Name: _unnamedTask<1>"

Is this to do with with the possible hardware problem you mentioned?

I using a USB-4432

Many thanks, 

[pwb]

for some reason I cannot upload the file, can I email it directly to you?

[dsb@NI]

Please do email me the file. My name is Doug Bendele, and my email is firstname.lastname@ni.com I have verified that the type of hardware triggering in the example is not supported by the 4431. Unfortunately, hardware triggering on an analog edge was not listed as a requirement when documenting the example, so there are a number of supported devices in the Example Finder that do not work with this example. I also verified that you have to modify the Block Diagram of the example in order to input valid IEPE current for the 4431. The default in the Create Channel VI is 4 mA.

 

I am writing an example to use a software trigger instead. I will post it when I am done.

Message Edited by dsb@NI on 01-15-2010 04:57 PM

[pktck]

Please do send me email, if the impact hammer test example is modified for USB-4431

ykkim821@gmail.com