Specification of Initial Damage

[bryan.williams]

Per "Modeling Damage Tolerance in Composite Materials"
http://help.autodesk.com/cloudhelp/2015/ENU/ACMPAN/files/GUID-FCEC8F7F-46AE-4A2A-8A16-0523E4372DDD.h...

It is possible to specify initial conditions for element state variables (SDV1) but not the state of individual layers or integration points. When modeling each ply discretely with 1 element, this is sufficient. However, when using shell elements this only gives the analyst two options: All plies have matrix failure and all plies have fiber failure. I would like the capability to say the first 3 plies have fiber failure and the last 6 plies have matrix failure.

This will allow me to start my model with better accuracy in my initial conditions.

Also, please see my comment that I added to the help article above.

Thanks

[lebsackm]

Hi Bryan,

Thanks for your input. You are correct that the damage tolerance implementation in its current state is limited to discrete layer models. However, there is a workaround that you can use for layered elements:

1. Create an additional material definition which uses degraded stiffness properties

2. Assign this degraded material to the appropriate integration layer(s)

The easiest way to create the additional material definition is via the HIN file (.hin). Here you can map the degraded material to the material you have already characterized. Then using the *MATERIAL keyword in the HIN file, you can enter degraded stiffnesses which will override the original material definition.

As an example, consider the following:

**
*MAP,FROM=NAME, TO=NAME
DEGRADED_MATERIAL,PRISTINE_MATERIAL
**
*MATERIAL, ORIGINAL NAME=DEGRADED_MATERIAL,
*MATRIX
100400, 100400, , , 700000, , ,

Where the stiffnesses reported represent degraded properties.

We have updated the 'Modeling Damage Tolerance in Composite Materials' Help topic as well to show a more complex example:

http://help.autodesk.com/view/ACMPAN/2015/ENU/?guid=GUID-FCEC8F7F-46AE-4A2A-8A16-0523E4372DDD

Thanks