Formula for Calculating deflection of Anti Intrusion plate.

[dharam]

Can anyone tell me how to calculate deflection of Anti Intrusion Plate. with a uniform pressure??
The plate is of an irregular shape since it is of same dimension as of front bulk head.
We will be using a Standard Impact Attenuator.

[Adambomb]

Umm...Why do you want to? We had a guy on the team that was obsessed with this, and I still haven't figured out why.

[Dash]

Originally posted by dharam:
Can anyone tell me how to calculate deflection of Anti Intrusion Plate. with a uniform pressure??
The plate is of an irregular shape since it is of same dimension as of front bulk head.
We will be using a Standard Impact Attenuator.


FEA OR maybe doing advanced mechanics of materials

[RStory]

Roark's Formulas for Stress and Strain has plate equations that should get you close. You'll probably have to approximate your anti intrusion plate as a rectangle.

[Francis Gagné]

The Roark's formula will only be somehow accurate if you stay in small displacement in the elastic range.

With the loading required for the standard IA you will have large plastic deformation (Assuming a bulkhead big enough for the attenuator) with the minimum thickness requirement by the rules for either steel or aluminum.

We used ANSYS non-linear static analysis to get in the ballpark, but I strongly recommend physical testing to validate. The FEA method is good, but the assumptions made on material, loading and boundary conditions aren't very precise.

For more information you can look at the following thread:

http://fsae.com/eve/forums/a/t...20905941#79820905941 (http://fsae.com/eve/forums/a/tpc/f/125607348/m/69420694941?r=79820905941#79820905941)

[BrendonD]

I ran a simple solidworks simulation with some numbers given to me by my IA guys as far as forces and placement of the attenuator on the front bulkhead. It gave me an overall max deflection past the plane. It looked OK. Then we ran the test. The resulting deflection was REAL close to the simulated number, like within 10% close (don't have the setup in front of me)

TL;DR: this loading scenario is very simple, an FEA approximation will do just fine given you know how to use some simple FEA.