Simulation of Non-layered Composite
Simulation of Non-layered Composite
(OP)
Hi there,
The composite I am looking to simulate has long fibre cast into a matrix (metal-matrix-composite), and is not layered up like an epoxy-carbon. The fibres are sometime uni-directional and sometime follow a 3D path.
The 'traditional' approach for composite FEA is to model the plies on top of a surface but this does not seem very appropriate to my composite.
What would be the best approach to simulating this non-layered composite?
I am interested in finding the best approach but so far I have considered (please suggest if there is a better method):
1. Just use the 'traditional' method in Ansys ACP of surfaces but with thick layers - least favoured.
2. Use the solid extrude feature in Ansys ACP, though I will still need to use layers.
3. Use the solid extrusion guide in Ansys ACP, though I will still need to use layers.
4. Model as a solid using orthotropic material properties in Ansys Mechanical, and use the orient element to align each element with the desired fibre direction at that point. Though I have the issue of applying a failure theories in Ansys Mechanical (best method is to use the composite damage tool).
Thanks!
The composite I am looking to simulate has long fibre cast into a matrix (metal-matrix-composite), and is not layered up like an epoxy-carbon. The fibres are sometime uni-directional and sometime follow a 3D path.
The 'traditional' approach for composite FEA is to model the plies on top of a surface but this does not seem very appropriate to my composite.
What would be the best approach to simulating this non-layered composite?
I am interested in finding the best approach but so far I have considered (please suggest if there is a better method):
1. Just use the 'traditional' method in Ansys ACP of surfaces but with thick layers - least favoured.
2. Use the solid extrude feature in Ansys ACP, though I will still need to use layers.
3. Use the solid extrusion guide in Ansys ACP, though I will still need to use layers.
4. Model as a solid using orthotropic material properties in Ansys Mechanical, and use the orient element to align each element with the desired fibre direction at that point. Though I have the issue of applying a failure theories in Ansys Mechanical (best method is to use the composite damage tool).
Thanks!
RE: Simulation of Non-layered Composite
RE: Simulation of Non-layered Composite
Hmm, I think method is good if you have say up to 20 fibres through a volume, but in this case it is thousands plus tows. Additionally, though I may know the general placement and path of a group of fibres, each fibre may deviate. I have test data for the composite as a whole, so I know the macroscopic response of the fibre-matrix together.
RE: Simulation of Non-layered Composite
RE: Simulation of Non-layered Composite
As a related question, am I correct in thinking the this approach also the best hand analysis method for non-layered 3D composites? That is, using the macro-isotropic properties of the part, finding stress at each point in the part, then use 3D versions of the composite failure theories to determine the location and mode of failure. Similar to the FEA method above, this method is only as good as the 3D versions of the composite failure theories.
RE: Simulation of Non-layered Composite
RE: Simulation of Non-layered Composite
RE: Simulation of Non-layered Composite
Can you share some picture or scheme showing this composite with visible fibre orientation ? Maybe it will be easier to suggest other method for this particular case.
RE: Simulation of Non-layered Composite
https://st.mascus.com/imagetilewm/product/hso/volv...
The fibre could be UD down the length of the arm and flow in a circle around the eyes.
https://www.douglasvalley.co.uk/images/21000/20215...
Similar to the above apart from the fibre would split at the fork and extra fibre would follow the large curve at the fork.
https://www.usedpartsfast.com/363701-thickbox_defa...
The fibre placement would be along the path of stress flow from the bottom attachment points to the top.
As mentioned, for all these examples the fibres are just imbedded in the matrix - no layering/plies.
EDIT: In terms of what the fibres look like in the matrix it is similar to the following image:
https://images.app.goo.gl/V72L7ZZw1exyqa8a6
RE: Simulation of Non-layered Composite
RE: Simulation of Non-layered Composite
Is there another approach you would suggest, instead? Perhaps in another piece of software? Or is it a problem without a current solution which can only be solved with testing & validation?
Additionally, if the failure theories in Anaya are not applicable, could Ansys still be used to determine accurate stress/strains at each point in the MMC?
RE: Simulation of Non-layered Composite
Ansys could calc accurate stresses if you can accurately model the material and if the input material properties are accurate.
RE: Simulation of Non-layered Composite
The choice of failure theory might be a problem here but you should be able to find some workarounds in scientific articles. Accuracy may not be very high but the whole thing is an approximation anyway.
RE: Simulation of Non-layered Composite
I'm having a look at Moldflow, Moldex3D and Fibersim.
I think the best current method I have available now is to either use a low number of thick plies and extrude into a solid elements within Ansys ACP, or use oriented elements with orthotropic properties all within Ansys workbench - to at least get stress-strain results.
Having a look through the MMC analyst section of Composite materials handbook. Volume 4, Metal matrix composites (Military Handbook - MIL-HDBK-17-4A Composite Materials Handbook, Volume 4 - Metal Matrix Composites) - it references Maximum stress, Maximum strain, Tsai-Hill, Tsai-Wu, Hashin, Puck and LaRC03 criterions. So I would think these are applicable.
RE: Simulation of Non-layered Composite
And I don’t know how those failure theories got into CMH-17 Vol 4, but I have never seen them validated for MMCs. Cripe another section of CMH-17 to have to go rewrite.