How Do You Calculate Torque for a Pusher Arm with a Dead Plate Friction?

[John9490]

TL;DR

Calculating torque for a pusher arm

Hello All,
I am designing a pusher arm for a project (Please refer attached picture), I need to calculate required torque to select a rotary cylinder.
The arm is mounted on a rotary cylinder and it has a dead plate underneath.

I understand we can calculate torque= Mass moment of Inertia x Angular acceleration, But How should we take the dead plate friction into account.?
Should i take any other parameter to calculate required torque other than this?

Thanks in Advance.

John.

 

[jrmichler]

You need a Free Body Diagram (FBD). Search the term if you have not yet had your statics class. That diagram will show the torque due to angular acceleration, torque due to force of gravity on the center of mass, and torque due to friction. Calculate each of those torques. Then add them up.

A general rule is that anything that puts a force on the system needs to be in the FBD. High speed movement, for instance, could require adding air drag to the FBD.