6 replies to this topic

[NeilR]

Other than walking into a local FSAE team and shouting 'free beer', is there an easier methodology or even software for calculating the basic kinematics of a push-rod suspension?

[NotAPineapple]

1. Keep all of your push rod points in a plane, then the problem reduces to 2D and you can do it on a drawing board

 

2. Get rid of the push rod and rocker and save some weight

[bigleagueslider]

The kinematic analysis of a basic double A-arm suspension using a pushrod and rocker arm linkage for the inboard spring/dampener should not pose too much of a challenge for the average mechanical engineering undergrad. There are many commercial software tools available that will do a good job of analyzing this type of suspension system.

[Greg Locock]

Neil - I thought you had Susprog3d? Not too sure if it does pushrods tho. There is no cheap, easy to use, solution I've found for mechanical linkage simulation, you might try this http://www.ar-cad.com/freecad/  - it is an unknown quantity to me in its present form, but 10 years ago I checked it out and it seemed accurate, if impenetrable.

 

You've got two separate problems, the first is the kinematics of the double wishbone, and hence motion of the pushrod attachment point. Once you know that then the easy bit is the gain of the pushrod/lever assembly as a function of the motion of the attachment point.

[NeilR]

Thanks for the replies. I do have a copy of Solidworks 2014 and I've been told I can model it in that. Will have to wait for a bit, but I'll crunch some numbers on paper too.

[Greg Locock]

Yes any of the big name cad packages will do it, the learning curve to get reliable results may be a bit steep. 

Edited by Greg Locock, 27 July 2015 - 11:20.

[NeilR]

Thank you, the emphasis was helpful. I may slip a bottle of scotch to a friend and ask him to do it then. He was involved in the original design and will have far more knowledge of solidworks than I. Will still do the number crunching on paper.

Edited by NeilR, 27 July 2015 - 12:41.