Motion Analysis | Animation of Mechanical Systems | Devon 3D CAD

Solid Modelling using 3D CAD is a great tool for analysing a moving Mechanical System.

Often, the simplest representation of the system is the best way of demonstrating the essential moving parts of a complex Mechanical System. How it works!

Animation of an hydraulic oil and gas drilling rig.

In this example I modelled the parts and assemblies as simply as possible. The purpose of the design was to show proof of principle for a hydraulic method of making the Draw Works for a drilling rig. The important principle to get across was the rise and fall of the drill head enabling drill rods to be attached as the cutting bit drilled further down into the earth.

The mast is static; the cylinders and pistons move in tandem from a starting position at the bottom to an ending position nine metres higher. I modelled the parts in different colours and assembled them with the correct mates (the pistons moved in and out of the cylinders till the drill head reached the top of its travel. This is where the animation feature of SolidWorks is so good at rendering this motion. I set up a continuous loop and saved it as an AVI video.

The animation was uploaded by the client to his website to show in the simplest terms how his Hydraulic System worked.

Motion Analysis of a seemingly simple mechanical assembly.

Most Design Engineers want to know how things work. In fact, if you don’t understand how it works you can’t design it properly! A client came to me with a request that I had never encountered before. He didn’t want me to design anything but to help him figure out why his own design worked so well!

This enterprising man wanted to make a powered version of a laborious manual task that was slow and tiring. He built a prototype. It worked; and over a few years he improved it and decided to explore the possibility of manufacturing it for sale. He was pondering an application for a patent and was required to produce an explanation of how the machine worked. I met him and together we watched the machine in action, trying to understand the motion that was making the system so effective.

I agreed to model the parts in 3D CAD as simply as possible and to assemble them with the same constraints as the working prototype. I put a mark on the main moving part so that it could be tracked as it moved past a static part of the machine. I repeated this at intervals till the machine came to the end of its motion. The result was a chart of the motion which I could measure and describe as an arc. Not an ellipse as we had both imagined. The client was happy that he could now describe the motion of his machine, and he is working his way forward!