Abaqus results

[sigmacoder]

Hi,

i try to simulate a 3 points bending of a glass plate with abaqus.

force 1kN !

young modulus = 7e10 Pa

Poisson's ratio = 0.22

- the plate is square (30 cm) , thickness 8.72 mm

- i use 3D extruded solid

- for the load i can't create a line load so i replace this load by pressure in a thin surface (2mm*30cm) applied in the center of the plate

- C3D8R element type

but the results are strange:

the maximum displacement is 0.672 mm !

is that realistic ? 1kN and just 0.672 mm of central displacement ?

thanks ...

 

[burningDiesel]

Why would it be wrong? Do a hand calc with simple plate theory and check.
Doublecheck your units too. Did you use at least 4 elements through the tickness?

 

[sigmacoder]

thanks to you for your answer.

can i have a analytical solution for this problem ?
another question is : can i use reissner mindlin theory ? because here i have line load ... not a uniform load at the upper and lower faces ...
for unit i use the international system units ...
i have exactly 4 elements through the thickness...

 

[burningDiesel]

If you consider your plate as a (wide) beam, deflection will be

1000*300^3/(48*7e4*300*8.72**3/12) = 0.48 mm.

For a 'wide beam' or plate, you will be working in plane strain more than plane stress, so I would guess the plate to be more stiff, when in your (finite element) case it is less.
Stress will be close to 40MPa so you'll break the glass first I'm afraid.

 

[sigmacoder]

thanks to you sdebock for your help, for this simulation abaqus gives 16 Mpa as maximal von mises equivalent stress ... but i'm not sur to use this criteria with this type of materials ... i will search ...