Newton’s Cradle with SolidWorks Motion

Newton's Cradle  

For this post I made a Newton’s Cradle.  It was a fairly easy build. The frame was just a couple sweep features.  The spheres were made using the revolve feature and then another sweep feature was utilized to create the arc that the string goes though.  The string was created using another sweep feature and then little spheres were created on the ends to simulate knots.  The main reason for making this was for the motion analysis that was applied to it after it was built.  In order to do the motion analysis, the SolidWorks Motion add-in needed to be activated.  Next the motion study tab was selected at the bottom of the window.  Gravity was added in to the study in the negative y-direction.  The next part was challenging at first.  This was trying to figure out how to get the spheres to simulate as if they were solid, thus not allowing them to pass through each other.  The contact feature was used to solve this problem.  A solid body contact was created for each pair of neighboring spheres.  For simplicity, I deselected the material and friction options under each contact pair.  I also set the restitution coefficient to 1.  Once I had all 4 contact pairs set up I was almost ready to begin.  Before I could run the study I needed to move one of the end spheres to a position other than where it would be at rest.  At this point I ran the study and achieved the results seen in the video above.  After running the study, you are able to generate plots of velocities, displacements, and other such quantities using the results obtained.  Shown below is the x-component of the velocity of two of spheres which are in contact with each other.  Take note that the velocity decreases as time increases which is what to be expected if you were to use a Newton’s cradle in real life.  I hope you enjoy.

  Linear Velocity Plot

Ian Jutras

Worcester Polytechnic Institute

Mechanical Engineering 2013

  Download Newton's Cradle

 

  • Todd Blacksher

    I did the same thing a few years ago when I worked for a VAR – so many fun things you can do with SolidWorks – thanks for sharing!

  • http://profile.typepad.com/weewilly Corporal Willy

    Mr. Jutras,

    You are doing excellent work with SolidWorks. I am enjoying your posts here because you inspire me with things that I have not yet thought of. Great work and keep on going. Many of us like to see what you have come up with. Bye.

  • Peter Barker

    It looks GREEAT! A good application of a Motion Analysis. I feel that it is important that people show how easy it is to get good, real results from an analysis.
    I’ll send in some of mine soon…