Load Sharing for two non-identical plates.

[JohnnyTBone]

Hello,

I have been given a project in which I have to design a ramp powered by a motor and gear-train. For the actual "deck" which the vehicles will roll on I have selected two 5mm Al 6061 T6 plates which are bolted together. The bottom plate will have 4 cut-outs taken from it and act as a frame (Drawn up on inventor and stress simulated and proves to be suitable). The maximum load the ramp must take is 100kg. How can I work out the load taken by the top plate and the load taken by the bottom frame plate? We haven't had to do anything like this in college yet.

Dimensions: Top plate - 2.5m long x 1.25 wide x 0.005 thick
Frame - Same as above but has 4, 1.175m long x 0.55m wide sections removed.

This problem is holding up the entire project as most everything else is sorted out and easy enough.

Pic attached below.

http://imgur.com/w5B2j

The black lines visible are the lines of the frame underneath the main top plate. Max deflection according to inventor is 17mm.

 

[LightHero]

To work out the load taken by the top plate and the load taken by the bottom frame plate, you need to consider the stresses that the ramp will be subjected to. The load taken by the top plate will depend on the weight of the vehicles that will be rolling up the ramp, plus any additional force that is generated by the motion of the ramp (such as momentum or acceleration). The load taken by the bottom frame plate will depend on the strength of the bolts used to attach the two plates together, as well as the stiffness of the material used for the frame. You also need to consider the deflection of the ramp when calculating the load taken by the bottom frame plate.