Sandwich structure 3 point bending test

Altair Forum User

Hey there,

 

 

I am comparing different ways to simulate a sandwich structure going through a 3 point bending test. In order to check if I am defining well the structure, I have calculated theoretically the maximum stress and compared it to the different simulations I have done. Below are the results of a 3 point bending test applying a total force of 110N on a test-tube of 100x15x10 mm :

 

Theoretically: Maximum stress- 7.33 MPa

 

1 solid (3D elements): 

<?xml version="1.0" encoding="UTF-8"?>

 

Plies (2D elements)

<?xml version="1.0" encoding="UTF-8"?>

 

Core (3D) +Plies (2D):

<?xml version="1.0" encoding="UTF-8"?>

 

The total dimensions of the three test-tubes are the same, as well as the boundary conditions. Therefore, I don't understand why I am obtaining such different stress results nor which would be the best option to simulate this test.

 

I hope you can help me with my problem.

 

Thanks in advance!

 

 

 

 

Altair Forum User

Hi Monica,

 

Can you request Composite Stress (CSTRESS) and check if that matches with your theoretical calculations?

 

If you still see a huge change when you compare, kindly share the calculation sheet and the model file.  Use this File Transfer LINK