Impact on Composite Plate

Altair Forum User

My greetings to the RADIOSS community. I am going to jump right into the subject that has been concerning me for the past month or so..

I am trying to simulate an impact on a composite plate. The aim of the simulation is to predict the behaviour of the composite under the impact load, estimate the ballistic value (impactor/projectile lowest speed at which penetration is observed) and find the most significant energy dissipating mechanisms (delamination, plastic deformation etc.).

In RADIOSS Block 110 which i am using there is a Ply Property (P19) and a Stack Property (P17). Has anybody used those before?

In both card images the user has to specify the angle of each ply (PROP\PLY\ANGLE and PROP\STACK\PHI) which makes not much sense since one is enough in my opinion.

Also in the stack property card there is a Zi entry for every ply which is supposed to be the Z position of layer i. That is also confusing, can anyone explain it a bit further? (http://www.altairhyperworks.com/hwhelp/Altair/hw12.0/help/hwsolvers/hwsolvers.htm?prop_type17.htm)

Lastly, do you think that using shell elements are the right choice for this kind of simulation?

Thanks a lot!

Altair Forum User

Hello,

 

i don't use it, but it looks like a standard procedure of defining a ply-based sandwich/composite definition.

 

/PROP/TYPE17 (STACK):

Since you can have a lot of plys (TYPE 19), it is necessary to define a table with informations about the composite. One isn't enough.

At the end you build here a stack of /PROP/TYPE19 (PLY) definitions.

 

If you set the Ipos-Flag, then you can define the real position of every ply (TYPE 19) in Local Z. See comment 24 at /PROP/TYPE17 help file.

To understand this, you have to read the description of Ipos:

 

Ipos: Layer positioning flag for reference vector Default = 0  (Integer)

= 0: layer positions are automatically calculated with regard to layer thicknesses. The coherence of global thickness with the sum of layer thicknesses is automatically checked.

= 1: all layer positions in the element thickness are user defined. Multiple layers may have the same special position. Global thickness is not checked in this case, since it needs to not be equal to sum of layer thicknesses.

 

Regards,

Mario

Altair Forum User

Thanks for your reply Mario.

 

So you are basicly saying that if i have the Ipos flag set to 0 i do not need to specify the Zi entries since it is done automatically. I am asking because comment 24 you cited above says:

'Layer positions must be defined if Ipos flag is active' which seems to imply that regardless of the selection of Ipos (0 or 1), if it is active, all Zis must be defined.

 

Also it looks like you misunderstood me about one being enough. What i mean is that specifying the angle of each ply once is enough. With Props17 and 19 the user has to do it twice, once in each property card.

Anyway, I found out how this works -the  two angles specified are added together to define the actual angle of the ply.

Lastly, the million dollar question. What about this material for the interface between two plies? Any suggestions (material model, properties) there?

Altair Forum User

Hi,

 

yes, if you don't define Ipos, then there is no need for Zi (look at the end of comments, there is a small table).

 

The angle is defined as Phi=Phi_i + Delta Phi, take a look at /PROP/TYPE19 comment 3...

 

Material between plies is defined by Mint_IDi (last parameter in /PROP/TYPE17, see also at comment 30).

Since i don't use Radioss i have no suggestion which one.

 

 

Regards,

Mario