# Need someone with engineering background to assist with statics calculation

1. Dec 15, 2015

### dmehling

I am looking for someone with mechanical engineering background who can assist me in making some calculations. I have an aluminum tray that is connected to a tripod and that supports a laptop. I want to get a lighter and smaller aluminum tray that can accommodate a tablet, but I don't know exactly how small and thin I could get it. I have spent countless hours attempting to find the answer and I asked a version of my question in both the physics and engineering sections of this forum but no luck. I tried to use a free fea cad program but it was a bit too complicated for me. I'm sure that an engineering student could easily figure this out and I would be willing to hire one for a reasonable rate. Better yet would be someone willing to volunteer a little bit of their time. I don't know how complicated this is, but I'm guessing that it shouldn't take more than 30 minutes to make some approximate calculations.

2. Dec 15, 2015

### hilbert2

You mean you want to calculate how thick a sheet of aluminum should be to be able to support a certain weight without bending?

3. Dec 15, 2015

### dmehling

Yes, that's basically it. If you do a Google image search for aluminum laptop tripod you will see many examples of what I'm trying to do. Right now I have an aluminum tray for my old laptop that sits on a tripod mount. I want the same thing for my tablet, but I want to reduce the weight of the tray as much as possible. The current aluminum tray is about 1/8" in thickness and easily supports my nearly 5 pound laptop, and I imagine it could probably support double that weight. Based on that, I would like to see if a 1/16" tray could work. Furthermore, I would like to know if I could make other changes in regard to the shape of the tray and any other weight reducing techniques.

4. Dec 15, 2015

### hilbert2

If you want to test different shapes of the tray, you need to do a finite element elastoplasticity simulation on a computer, and input the shear modulus and yield stress of aluminum as parameters.

5. Dec 15, 2015

### dmehling

I really need someone who can do that for me, since I definitely don't have any experience with engineering. I played around with a free program called Lisa for the last hour, and I really have no idea what I'm doing.

6. Dec 16, 2015

### CWatters

How much force do people apply to the touch screen of a tablet? Perhaps more than the tablet weighs sometimes? They may even rest their arms/hands on the tray?

7. Dec 16, 2015

### jim hardy

Some things are best determined empirically.
Stiffness without thickness .let's think here ...........
Cardboard is corrugated for a reason. Cooking trays have a lip for a reason. Eggshells are curved for a reason.
Can you put some curvature in your design ? or roll an edge ?
I'd go to local hardware store and buy some aluminum sheet for experimentation. Or a metal salvage yard - mine gets a lot of interesting aircraft structural parts....

old jim