General Mechanical

Symmetry Boundary conditions

• maismn
Subscriber

Hello,

I have modeled a plate (1000x1000 mm)of 3 layers (TOP, CORE.BOTTOM), which the top and bottom layers are reinforced composite material and the core material have a high yield strength .Also, the plate is simply supported from all of the sides. a distributed load is in the middle of the plate which is applied in a square area (100x100 mm).(i applied it as pressure load )

I modeled a quarter size of this plate (quarter load area).i found the tow symmetry region in the mechanical .

THE problem is the results for the quarter plate  is not the same for the full plate !

Is there a certain supports should be applied in the symmetry region ?

Should the quarter plate pressure be 1/4 the full plate pressure?

Finally, What is the acceptable difference between the full ans quarter results ?

• peteroznewman
Subscriber

There are many ways to make a mistake. The lack of agreement between the full and 1/4 model might be due to a mistake in one or both models.

How do you do a simply supported edge of a 3-layer sandwich?

What are the material properties of the composite plate?  Composites often have orthotropic material properties, meaning they have different modulus in different directions. Are you using an orthotropic materials?

• maismn
Subscriber

The composite material is defined as orthotropic materials and yes it has a different modulus in different direction. The material is graphite epoxy

T300 /5208 , and has a fiber orientation angle symmetric 30/-30/-30/30 .

The simply supported is as follow:Z-axis edge , zero deformation in all directions(fixed support) and fixed rotation in both X&Y axis,

X-axis edge, zero deformation in all directions(fixed support) and fixed rotation in both Y&Z axis.

Thank you .