×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Relate measured strains to input load

Relate measured strains to input load

Relate measured strains to input load

(OP)
I am working on a project where strain has been measured on various places on a bridge structure that supports an agitator. I have been tasked to relate the measured strains to the input load from the agitator in the center of the bridge structure.

Is there any literature or examples that I can follow to obtain this outcome? I know I need to obtain coefficients that relate the applied force to the measured strain but am lacking some direction of how to do this.

Any help would be appreciated.

 

RE: Relate measured strains to input load

That's the concept of an electronic scale.  Proper placement of strain gages can allow you to backcalculate the applied load, typically based on the bending stress in the material.  Should be calibrated for accuracy, though.

RE: Relate measured strains to input load

The stress analysis of the bridge should provide you the means of estimating the stress at the strain gauge location, to compare with the strain gauge reading.

RE: Relate measured strains to input load

Bevan:
Get your Mechanics of Materials text books out and do a little review.  You might be a bit over tasked if you don't remember that stress and strain are related through the modulus of elasticity of the material.  You should get some info. from the people who installed and read the strain gages, as to their orientation, correction factors, etc. for a meaningful and usable strains.  Knowing the material, you can then calc. the stress in the member, in that particular point and orientation.  Someone must have known the stresses and their orientation which you were ultimately looking to check.  Then you must understand the structure well enough to track that stress back to the machine actually inducing the load.  Is it a pure tension stress in a hanger?  Is it a bending stress in a beam on which the machine rests?  Is it a stress on a member of the structure far removed from the machine inducing the load?  That req'rs. some structural analysis.  Maybe all you want to know is that the machine in question is not stressing the material beyond yield; then you must know the grade of the material.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources