Structural Support Triangles for a rope-climbing robot

[joshbr32]

sorry if this is in the wrong spot or what not

So my school has this robotics club and we need to build a robot to climb a rope as well as do other things. But focusing on the rope climbing I need to design 2 plates that can support the weight of the robot (~150lbs)
The plates themselves are large vertical triangles 18" long and 24" tall, placed on either side of the robot 3 bars crossing the two, at the top there will be the main shaft that holds the climber (a hook that spins and grips the rope pulling itself up as the rope wraps around it) and two structural support bars that are lower (around the middle).

So getting to the point I have been told that adding triangles inside will make this plate less likely to snap under the weight and I am wondering if I was to have 6 tiers of triangles, with the space between them being 1" thick, what would the dimensions of the smaller triangles? I've tried to find them via trial and error but it isn't working (the triangles need to be exact copies of one another yet the space in between them should be like one line, if you understand what i mean, but when i do it the lines are offset from one another)

BTW the metal I am using is Aluminum 60601, that is 1/8" thick
I am using inventor if you guys want the file I started to make so you can see what i did wrong I can upload it for you (Link to file+ picture explanation)

 

[Baluncore]

Welcome to PF.
Cutting triangular holes will significantly weaken the plate because during flexing under load, energy will be focussed into the sharp corners.

If you need to lighten the plate, consider drilling circular holes, (with a bi-metal hole-saw), rather than triangles.
Make sure the edges of the holes are smooth.

 

[Nidum]

May be better to design an optimised frame from scratch .

Set out the positions , magnitudes and directions of all the forces acting in your system on a diagram and then sketch in the minimum number and size of metal links needed to make the system stable and adequately strong . Merge and simplify this arrangement of links into a shaped plate with cutouts .