Ansys Learning Forum › Forums › Discuss Simulation › General Mechanical › How will the reaction moment on the support be distributed in terms of forces in this model? › Reply To: How will the reaction moment on the support be distributed in terms of forces in this model?

January 14, 2022 at 2:24 pm

peteroznewman

Subscriber

Please refrain from mixing two different topics in one discussion, it muddies the water.

We agree that there is no static solution to the stated problem of arm on a revolute joint, since you clarified that there is a follower force at the tip.

You want to know the reaction forces at the revolute for a dynamic analysis. What are the initial conditions? What direction is gravity?

If gravity is parallel to the rotation axis, then there is a constant moment on the revolute joint of m*g*r where m is the mass of the part, r is the radial distance to the center of mass and g is the acceleration due to gravity.

The arm will develop angular velocity, omega, due to the follower force. Centrifugal force acts along the length of the arm and will be equal to m*r*omega^2.

All of these effects as well as the transient effects from the flexible arm can be modeled in Transient Structural.

We agree that there is no static solution to the stated problem of arm on a revolute joint, since you clarified that there is a follower force at the tip.

You want to know the reaction forces at the revolute for a dynamic analysis. What are the initial conditions? What direction is gravity?

If gravity is parallel to the rotation axis, then there is a constant moment on the revolute joint of m*g*r where m is the mass of the part, r is the radial distance to the center of mass and g is the acceleration due to gravity.

The arm will develop angular velocity, omega, due to the follower force. Centrifugal force acts along the length of the arm and will be equal to m*r*omega^2.

All of these effects as well as the transient effects from the flexible arm can be modeled in Transient Structural.