Force & Torque Equations for a Twist Tie

In summary, the conversation discusses the force and torque equations needed to describe an experiment involving a thin metal wire being bent around a cylindrical tube, which is then "sliced" along its wall thickness. The wire is then twisted together to form a double-helix and a force/torque is applied to tighten the wire around the cylinder and bring the "sliced" portion back together. The conversation also mentions the application of an upward "pull force" to snugly fit the wire around the cylinder. The main question posed is how much force/torque is needed to bring the "sliced" portion of the tube back together using the "twist-tied" wire.
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pduves
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Hello! I'm posting this because I cannot find this type of question and analysis anywhere!

What are the force and torque equations describing the following?
1. A thin metal wire is bent around the OD of a cylindrical tube (wall thickness, t) perpendicular to the axis.
2. The cylindrical tube is "sliced" along its wall thickness in the radial direction (creating a disconnection of the wall thickness along the "spine" of the cylinder). Because of the shape of the cylinder, the "spine" portion opens wider as the cylindrical walls come apart.
3. The wire is bent around the OD so the ends of the wire come together above the "sliced" area.
4. The wires begin to "twist" together (like a twist-tie) forming a double-helix.
5. A force/torque is applied to twist the wire ends around each other (double-helix). The force/torque pulls the wire tighter around the cylinder and slowly brings the "sliced" portion of the tube closer together.
6. Along with the force/torque on the double-helix wire, an upward "pull force" is also applied to pull the wire to a snug fit around the cylinder.
7. The separated, "sliced" portion of the wire slowly comes together. The separated walls are connected again.

How much force/torque is required to bring the "sliced" portion of the cylindrical tube back together using the "twist-tied" wire?

Hope this makes sense! I think its a great physics problem! Thanks!
 

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Applied torque to tension in cable analysis + Deformation of split cylinder under distributed radial load analysis + Tension in cable wound on drum with friction analysis .
 
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1. What is a twist tie?

A twist tie is a small piece of wire or plastic coated wire with ridges or grooves that is used to secure the openings of bags or packages. It is typically twisted around the neck of the bag or package to keep it closed.

2. How does a twist tie work?

A twist tie works by exerting a force on the bag or package, pressing the edges together and keeping them closed. The ridges or grooves on the twist tie create friction with the bag or package, preventing it from slipping open.

3. What is the force equation for a twist tie?

The force equation for a twist tie is F = μN, where F is the force exerted by the twist tie, μ is the coefficient of friction between the twist tie and the bag or package, and N is the normal force applied to the twist tie.

4. How does torque affect a twist tie?

Torque is the measure of a force's ability to rotate an object around an axis. In the case of a twist tie, torque is important because it determines how tightly the twist tie can be twisted around the bag or package. The greater the torque, the tighter the twist tie will hold the bag or package closed.

5. What is the torque equation for a twist tie?

The torque equation for a twist tie is τ = rF, where τ is the torque, r is the distance between the point of rotation (the twist tie) and the point where the force is applied (the bag or package), and F is the force applied by the twist tie.

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