Help An issue with a cantilever tube instrumented with strain gauges.

In summary, the conversation involves the development of a cantilever tube instrument with strain gauges and rosettes, and the issues the speaker is facing with its sensitivity to loads. They mention looking into the zero load null and gauge factor, and then mention a separate task involving writing a program in C++ for data collection. The speaker mentions being new to C++ and asks for recommendations for resources, and someone suggests checking a programming sub-forum.
  • #1
babistopher
15
0
I am working on the development of an instrument which can be simply thought of as a cantilever tube. This tube is instrumented with strain gauges to measure the X/Y strains and two sets of rosettes, each consisting of two strain gauges at 45 degree. Note that the X/Y are 3-wire half bridge and the rosettes (for torque) are full bridge. I have been having several issues with this instrument and I am trying to figure them out one at a time.

First of all, when I apply a small load (around 1 N) I get an output of around 12 N if not more. Would anyone know why the gauges seem to be so sensitive to the loads? I have taken into consideration the gains of the amplifier and filter in the circuit. Would lead wire resistance be the culprit despite it being a 3-wire connection (which apparently negates its effect)? What about soldering? That's my first of many questions! Any help is appreciated!
 
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  • #2
The first things I would look at are your zero load null and the gauge factor input into your readout system.
 
  • #3
Sorry I didn't reply back. I had to work on something else for the past couple of weeks. Thanks for that. I'll look into those things whenever I can.

I do, however, have a more urgent task at hand and was hoping you could help me out. I am supposed to write a program using C++ that will take data collected by two separate DAQ cards and save them as either a text or spreadsheet file. Now, I'm still new at C++ and I do not even know where to begin. I have been looking for some literature or tutorials that might guide me online but I have had no luck. Would you know of any sites I could look into for that? Thanks.
 
  • #4
Sorry. I am not a programmer. I haven't done anything outside of Labview when it comes to DAQ. I don't even think I could tell you what the first line of C++ code should say.
 
  • #5
babistopher said:
I have been looking for some literature or tutorials that might guide me online but I have had no luck. Would you know of any sites I could look into for that? Thanks.

Try the Programming sub-forum...

https://www.physicsforums.com/showthread.php?t=15689
 

What is a cantilever tube instrumented with strain gauges?

A cantilever tube instrumented with strain gauges is a device used to measure strain, or the deformation of an object, in a cantilever tube. It is typically made up of one or more strain gauges attached to the surface of the tube, which can measure minute changes in length or shape caused by external forces.

How does a cantilever tube instrumented with strain gauges work?

The strain gauges on the cantilever tube are connected to a Wheatstone bridge circuit, which measures the changes in electrical resistance caused by the strain. This allows for precise measurement of the strain on the tube, which can then be used to calculate other parameters such as stress or displacement.

What are some common issues with a cantilever tube instrumented with strain gauges?

Some common issues with a cantilever tube instrumented with strain gauges include improper installation of the strain gauges, which can lead to inaccurate measurements, and external factors such as temperature changes or vibration that can affect the readings. It is important to carefully calibrate and maintain the instrument to ensure accurate results.

What are the applications of a cantilever tube instrumented with strain gauges?

Cantilever tube instruments with strain gauges are commonly used in structural engineering and material testing to measure strain and stress in various structures and materials. They can also be used in research and development for studying the behavior of different materials under different conditions.

How can I troubleshoot issues with a cantilever tube instrumented with strain gauges?

If you are experiencing issues with a cantilever tube instrumented with strain gauges, first check for any loose connections or incorrect wiring. You may also want to calibrate the instrument again to ensure accuracy. If the issue persists, consult the manufacturer or a trained technician for further assistance.

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