Simulation of a Simple Pendulum

[equitus.engineering]

Hello all,

I am trying to figure out the best way to simulate the swinging of a simple pendulum, over a 30 degree angle either side of the vertical axis. Then I'd like to look at the stresses induced at the fixing points due to this oscillation.

Any help anyone can offer will be highly appreciated.

Regards,

Raam

[John_Holtz]

Hi Raam,

As a first approximation, I would setup a linear static stress analysis and apply a Rotational Force load (that is, a centrifugal load). You can hand-calculate what the RPM is as the pendulum passes through the low point, and enter that in the Rotational Force. 

[equitus.engineering]

Hi John,

Thank you for your response. I ran a trial model to get the solution logic right. I have attached three images.

Slide 1: describes how the rotational velocity has been applied

Slide 2: shows the result for load application in one direction

Slide 3: shows result for direction reversal

All settings are the same, with the only difference being direction reversal.

As you can see in slide 2 and 3, the direction of result isn't changing with the change in load direction.

Am I doing something fundamentally wrong or is this some kind of a display bug?

Any help you can offer will be highly appreciated.

Regards,

Raam

[Anonymous]

As Long as you do not add any acceleration, the load is only the centrifugal force. Remember it is a static analysis with no motion at all. And the centrifugal force is the same, no matter if the pendulum turns clockwise or counterclockwise.