August 6, 2021 at 9:23 pm
peteroznewman
Subscriber
In preparation, do a Modal analysis and find out the first natural frequency of the beam f (Hz). T = 1/f is the period of the first natural frequency in seconds.
Use a Transient Structural analysis and use a 3 step analysis.
Step 1 turn off Time Integration while the Force ramps up to the value you want and deflects the beam. Set the End Time to 1e-5 seconds
Step 2 turn on Time Integration and leave the Force at that same value. This is to establish a zero velocity initial condition. Set the End Time to 2e-5 seconds
Step 3 set the initial time step size to T/100 set the Minimum time step size to T/1000, set the Maximum time step size to T/20. Set the end time to 10T to see 10 cycles.
Under Damping Controls, set the damping to 0.01 for the frequency f.
Set the Force to 0 and Step applied, not Ramped. If you can't figure out how to do a Step Applied change for the Force, make it a 4 step analysis and insert a new step 3 where the force ramps down to 0 with an End Time of 3e-5 seconds, then setup step 4 as I described step 3 previously.