Measuring Stress on Tubular Steel Chair Frame

[JD88]

I am going to need to be experimentally measuring the stresses in a tubular steel frame. The tubular steel has a 0.75" OD and a thickness of 1/16". The frame is for a chair and I need to determine the stresses at various locations and determine whether or not the stress is below the endurance limit of steel. What is the best way to measure these stresses. I assume strain gauges but I have very little experience with them so I am not certain. Any advice would be greatly appreciated.

 

[xxChrisxx]

Just a little niggly thing because you probably know this already, you never measure stress (you acutally can't measure stress).

You always measure strains, so strain gauges are the best way to go.

To be honest this isn't something we can really help with with the information you have provided, talk to technician as there are so many different types of strain gauges it'd be impossible to say what would be the best for this application.

 

[FredGarvin]

What advice do you need? Are you going to use strain gauges? It seems like you're not sure yet.

There's an art to using them properly and there is an even more delicate art to installing them properly.

Will you be the only one doing this or will you have experienced users helping? If not, you have a lot to read up on. Vichay's website has a lot off valuable information.

Things you will have to consider are

- The material and expected amount of strain in the locations being measured.
- The environment
- The direction(s) being measured (single vs. rosettes)
- Electrical system employed

You really have a lot to look into. I suggest starting reading anything from Vichay. You will also have to be proficient in the constitutive equations required for calculating the stresses from the measured strains.