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Comment on Strain Gauges Explained by James Wren

James Wren — Wed, 01 Feb 2012 12:02:05 +0000

Hello Teer,

Thank you for asking a question on our blog.

Your question is quite simple, if there is a piece of metal which is vibrating does this vibration induce any strain in the metal?

The answer is not so simple, it might be and it might not be inducing some strain. It depends on the vibration and if the metal is supported well or not, the size of the metal mass and so on.

The basic rule is this is the metal is bending in anyway then there will be some stress/strain.

I would expect any piece of any metal that is vibrating to move around as it’s own structure and therefore I would expect various amounts and directions of stress and strain in the material.

I hope this answers your question

Comment on Strain Gauges Explained by Teer

Teer — Wed, 01 Feb 2012 11:43:28 +0000

Hello,

I am working with strain gauge measurement on the electrical steel lamination, any effect with strain if while I am measuring the lamination vibrate ?

Thanks.

Comment on 9 Great Engineering Animations by shuja zaheer

shuja zaheer — Sun, 29 Jan 2012 18:20:37 +0000

masterclass

Comment on Torsional Vibration, Tacho Pulses And Aliasing by Lyn Greenhill

Lyn Greenhill — Thu, 26 Jan 2012 16:27:28 +0000

I used to use tach pulses to measure torsional vibration but do not any longer. I have not run into any aliasing problems with this method probably because I demodulate the signal prior to FFT processing. Anyway, I have switched to shaft mounted strain gauges and rotating telemetry for torsional measurement, which produces a direct measure of torque if you calibrate or simply calculate the sensitivity of the gauge to twist. I can send you some examples of how this is done and what kind of results are produced if you are interested.

Comment on Strain Gauges Explained by James Wren

James Wren — Thu, 19 Jan 2012 13:53:51 +0000

Hello Bruce,

You are quite correct, thank you for pointing this out.
I have corrected the article.
The formula is only an example and is not actually correct in any case it just intends so show the process in action rather than any hard results.

I don’t think being correct is being pedantic!

Comment on Strain Gauges Explained by Bruce Hefford

Bruce Hefford — Thu, 19 Jan 2012 13:02:57 +0000

Dear James,

Sorry to be pedantic, but the second equation for resistance of a piece of copper wire appears to be incorrect. The wire is stretched to 2m and its diameter decreases to 0.5mm^2, which equates to 0.0005m^2, not 0.005m^2. So the resistance is 0.144 Ohms, not 0.00144 Ohms.

Yours sincerely,

Bruce Hefford

Comment on Strain Gauges Explained by Bruce Hefford

Bruce Hefford — Thu, 19 Jan 2012 12:57:41 +0000

If you are still interested in wireless measurement it is worth having a look at this website :

http://www.datatel-telemetry.de/en/

Comment on 10 Cool Engineering Videos by Engieering Videos

Engieering Videos — Wed, 11 Jan 2012 19:19:22 +0000

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I am your RSS Reader.

Regards:
Online engineering Video lectures

Comment on Strain Gauges Explained by James Wren

James Wren — Sat, 24 Dec 2011 09:45:25 +0000

Hi Pankaj,

It sounds like your using the strain gauges as part of a weigh scale.

Basically the strain gauges are put under load by the item your measuring, this changes their resistance values. The load puts the material the gauges are on under strain.

When you put a known mass, like 1 kg for example, on the scale you monitor the voltage change and therefore the resistance change in the elements of the bridge, hence you have a known voltage change for a known mass. Thus you can calculate how the voltage will change for any mass and therefore you have a linear sensitivity in volts per kg or unit.

Comment on Strain Gauges Explained by pankaj

pankaj — Fri, 23 Dec 2011 06:59:42 +0000

hello.
i am doing electronics engg. i am working on real time experiment of weight measurement using strain gauge using labview software and data acquitation cards. please let me know how strain gauge works in this experiment.

Comment on Vibration : Measure Acceleration, Velocity or Displacement? by Yeugeny Chirkov

Yeugeny Chirkov — Tue, 20 Dec 2011 15:39:45 +0000

It is known the better way to difrerentiate the noisy signal -to approximate the signal before.
Best Regards,
Yeugeny

Comment on 9 Great Engineering Animations by srikanth

srikanth — Thu, 15 Dec 2011 12:31:26 +0000

superb easy to understand

Comment on Interpolation Versus Resampling To Increase The Sample Rate by Peter Webster

Peter Webster — Thu, 15 Dec 2011 11:33:56 +0000

If you import data that has some data points missing but it includes a reference time signal, is there a way of resampling that references this time signal to end up with a signal with a constant sample rate?

Comment on A New Partner In Condition Monitoring – VibrationDiagnostics Ltd by Chris Mason

Chris Mason — Thu, 15 Dec 2011 06:59:29 +0000

Dear pratiy, thank you for your comment. You can request a handbook here… http://www.prosig.com/formHandbook.html …or email sales@prosig.com with your address and we will arrange for handbook to be sent to you.

Comment on Negative Frequencies – What Are They? by Nigel Maponga

Nigel Maponga — Thu, 15 Dec 2011 06:45:18 +0000

Thank you for all the information you post, I do both VA and remedial work i.e balancing and alignment and this particular issue has helped me a lot in understanding phase references ,an important aspect in dynamic balancing.

Comment on A New Partner In Condition Monitoring – VibrationDiagnostics Ltd by pratiy kaenty

pratiy kaenty — Thu, 15 Dec 2011 06:36:44 +0000

I need Noise & Vribration Measurement handbook free.
thank.

Comment on Interpolation Versus Resampling To Increase The Sample Rate by CJ

CJ — Wed, 14 Dec 2011 12:27:12 +0000

I have some comments regrding this blog which, hopefully, you can clarify.

Regarding the first example, interpolation looks to be far superior, recreating the original pure sine wave. Resampling looks to creating local variations rather than responding to them.

Regarding the second example, I suspect the resampled signal contains data above the Nyquist frequency of the original sampled data at the peak and therefore violates Shannon’s sampling/reconstruction theory. Assuming the data is sampled correctly the interpolated ‘signal’ (I know it’s still sampled) is the only one that could result in the sampled data. [others would not be sampled correctly at the same rate bacause of their higher frequency content].
Also the interpolated data does not appear to coincide with the original data points

Comment on Data Smoothing : RC Filtering And Exponential Averaging by Julia Truchsess

Julia Truchsess — Mon, 12 Dec 2011 16:52:09 +0000

Thank you thank you thank you. You could read 100 DSP texts without finding anything saying that an exponential averaging filter is the equivalent of an R-C filter.

Comment on What’s All The Noise About? by jason @ soundproofing

jason @ soundproofing — Thu, 08 Dec 2011 01:18:10 +0000

Cheers mate. a great help. There’s a lack of noise on the internet – or so I thought!

You’ve just proved me wrong!

Comment on Data Smoothing : RC Filtering And Exponential Averaging by Chris Mason

Chris Mason — Wed, 07 Dec 2011 09:24:39 +0000

Mike, thanks for spotting that. I have just checked back to Dr Mercer’s original technical note in our archive and it seems that there was error made when transferring the equations to the blog. We will correct the post. Thank you for letting us know