Armour

[gravity]

I always try to think offensive rather then defensive... Gravity 3 had 3 mm stainless steels around the back, and 4-6 mm polycarbonate on top and nothing more...

[typhoon_driver]

hehe i think we took the offensive rather than defensive thing to the extreme as our weapon is our armour!

[jamesb]

less money on armour executioner, more on bribes

[julian]

WJ, I thought that your armour consisted of rows of fire extinguishers.

[icemanuk]

Bribes? Hmmm never thought of that We are confident that our re-designed Executioner will perform admirably for us at the world champs! (famous last words) It was performing very well in series 7 until our normally bullet proof vantec blew a FET We have now bought a better one!

[gravity]

@ Julian:

Gravity 5 will pack 4 of them... so thats quite a lot of Fire extuinguisher indeed... I just dont think the event organisers would be so happy if I put them on the outside of the robot... would be neat though

[talulah]

For a compromise, and still very cheap, you could use much thinner steel (say 2mm or even 1mm) and mount it onto 6mm or 8mm plywood backing. The steel acts as armour against cutting tools and flames, and the plywood behind supports the steel against impact weapons. The result is significantly lighter than 6mm steel.

It would be interesting to do some tests on a composite like this, and obtain hardness & strength values. Ive got hardness and strength values for lots of other materials ona page of my site here: http://homepages.which.net/~paul.hills/Materials/Materials.htmlhttp://homepages.which.net/~paul.hil...Materials.html

[talulah]

Im not sure Daniel, UHMW Polyethelyne is heavier (941 kg/m^3 compared with about 615 kg/m^3.

Im not sure how to compare the impact properties. It is there to support the steel, so I guess something like the Flexural Modulus (0.75GPa compared with 9.3GPa for plywood) shows that the plywood is a lot more resistant to bending, although the polyethylene has a slightly higher ultimate tensile strength.

Im no expert in materials science so I wouldnt like to say really.