×
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

Circumferential Pressure on a member from choked wire

Circumferential Pressure on a member from choked wire

Circumferential Pressure on a member from choked wire

(OP)
Does anyone know of any guidance for calculating the pressure exerted on a member from a wire wrapped around in a choked arrangement (think lasso)?

---------------------------------------------------------------------------------------------------------------------
pimp

"The world keeps turning, it keeps me in my place; where I stand is only three miles from space"
Spiritualized

RE: Circumferential Pressure on a member from choked wire

A lasso is an excellent way to look at the problem. Assume no friction (reasonable for a static condition) and that the "thing" lassoed is circular (like a post or pipe).

The only way the lasso can apply force is thru tension (hoop stress).

The only way the post can resist "choking" is by a uniformly distributed, radial force directed outward.

For a moment, assume the post is "crushable" and 14 inches in diameter, for example. Pull on the lasso to shorten the noose (the circumference of the post). Say that the lasso is shortened  4 inches - the post diameter is crushed by 4 inches divided by Pi = 1.27 inches.

The tension in the lasso has a 3.14 to 1 mechanical advantage (4 inch/ 1.27 inch) on the total radial force resisted by a "non-crushable" post.

For the hypothetical dimensions given above, assume tension in the lasso is 120 pounds. Then the total "choking" force that must be resisted by the post is 120 lb x Pi = 377 pounds. For a unit length of the noose this would be  377 lb / 14 inches / Pi = 8.57 lb/ inch of noose length.

Notice that the total force resisted by the post (377 pounds on this case) is independent of the post diameter.

www.SlideRuleEra.net idea

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