×
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

Get value from a nonlinear stiffness graph

Get value from a nonlinear stiffness graph

Get value from a nonlinear stiffness graph

(OP)
I have got a nonlinear graph for a nonlinear spring on the paper. Is that possible to scan it and transfer to a recognizable table for the phy. properties of the spring?    Matlab can do so?
or, The only way is to select dozens of point and cauculate the Stiffness by them with certain algorithm?

RE: Get value from a nonlinear stiffness graph

Your statement seems to presume that there is a single value for the stiffness of the nonlinear spring.  For a linear spring, there is one value of stiffness; however the very definition of a nonlinear spring is one in which the stiffness varies with displacement.

Typically nonlinear stiffnesses are handled either in a piece-wise linear fashion (which would require 'picking the points'), or they are described using a discrete equation which is then curve-fit to the existing data (generally using a least-squares fit).

I have in the past scanned in nonlinear curves, then utilized cad software to extract a curve which is then discretized in many different points.  These points can then be fed into any math processor (matlab, mathcad--even excel) and then curve-fit utilizing appropriate assumptions.
Brad

RE: Get value from a nonlinear stiffness graph

(OP)
I have in the past scanned in nonlinear curves, then utilized cad software to extract a curve which is then
^^^^^^^^^^same to my case^^^^^^^^, But what is the software and How to discretize to points. Do U mean raster to vector conversion? Is there any other simple way?

Anyway thanks!

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