I have previously posted on Dynamically Defined Dancing Pendulums, using the Strand7 FEA program to generate the motion of a series of pendulums of varying length.  I have now updated that video using the latest Beta version of the program (Rel 3):

For those who don’t have access to the Strand7 package, just enjoy the video, for those who do, read on.

I have now uploaded the Strand7 files used to create the videos for download:

DancingPendulums.zip

The zip file includes versions for the current release (2.6), and the Beta version of Release 3, which is available for preview by supported users.

To generate the animation, open the ST7 file and run a non-linear transient dynamic analysis, which you can then use to create an animation from any chosen viewpoint and play-back rate.  The analysis has 18,000 time steps, which with default view settings takes 3 hours or more to complete.  To speed things up, switch off the log file and convergence graph displays, so there is minimal screen updating with each step.  This reduces the computation time down to about 10 minutes.  See the previous post for more details on the set up of the model and analysis parameters.

The animation can be saved in Strand7 format, or converted to an avi file.  For upload to WordPress I used Snagit to capture the video on-screen, then saved as an mp4 file, which can now be uploaded to run directly from WordPress.