mechanical vibrations and LabView

[StressLess]

Hi. This is my first post in here.
I'm a mechanical engineering student. I'm taking mechanical vibrations course this summer. My question is, how would LabView help me in that field ??

Thanks in advance.

[Buntoro]

Many things.
Labview can show you an analysis in time axis and and can give you the
spectrum
FFT analysis can be also done


"StressLess" schrieb im Newsbeitrag
news:5065000000080000003B960000-1042324653000@exchange.ni.com...
> Hi. This is my first post in here.
> I'm a mechanical engineering student. I'm taking mechanical vibrations
> course this summer. My question is, how would LabView help me in that
> field ??
>
> Thanks in advance.

[dsb@NI]

The Full and Professional Development versions of LabVIEW also offer filters that you can use for signal conditioning, standard windows used for vibration test (Hanning, Hamming, Flat-top, force-exponential, etc), frequency response, cross spectrum, and more.

If you also have the Sound and Vibration Toolset you have access to all the above-mentioned functionality as well as time- and frequency-domain integration to convert acceleration data to velocity and displacement, weighting filters, extended measurements (like peak search, power in band, and units conversions), STFT (for measuring transient vibration signatures, and swept sine analysis.

These tools are very much directed at analyzing acquired data rather than simulating the frequency response. Ho
wever, LabVIEW is a programming language - you can write your own routine (pretty easily) to simulate the desired data given mass, damping, and stiffness matrices or given mode shapes and natural frequencies.

One element that is not included in any package in LabVIEW and is not so easy to implement on your own is the structural identification. There is no tool in LabVIEW to identify mass, stiffness, and damping or the modal representation of the structure from simulated or experimental data. I have used LabVIEW and the Sound and Vibration Toolset to obtain Operational Deflection Shapes (ODS). You would need to use another program (I-DEAS is one example) to perform a true structural identification. In this case, LabVIEW would just provide a convenient platform to acquire, condition, process, and store the data.

[chutla]

Dear Stressl


Depending on what kind of hardware you have, you can do some pretty amazing stuff in the Mechanical/acoustics realm. With a simple soundcard and a microphone, for example, you can do real time graphing in the time domain, and then use FFT to selectively plot your frequency components. There is also, for example, an EXTRACT SINGLE TONE function that can pull a resonant frequency out of an EXTREMELY noisy environment (assuming it IS relatively periodic) in nature. There is a vast assortment of analytic tools, such as Cross power calculations that are invaluable in acoustic measurements, as well.
The best way to learn this is to simply examine all the available nodes in Labview. You can easily miss out on some very cool functions if you go
strictly by the documentation. The best source for Labview documentation, as you will discover, is this forum!

Enjoy!

eric

[DNgineer87]

I am trying to use Labview to obtain Operating Deflection shapes, but the magnitude of the imaginary plots is wrong. 

I have triax accelerometer data from multiple locations on a structure.  I'm taking the Autopower of the response and the crosspower of the response and reference.  I then use the magnitude of the Autopower, and the phase of the cross power to create a complex array which I then convert to Real and Imaginary for My ODS plots.  With this technique I get amplitudes that are much too low or much to high. 

Would you be so kind as to share how you did it, or where I've gotten off track?