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Material orientations. Mat-prop compatibility.

Altair Forum User

Hi @Prakash Pagadala,

I have two issues to solve.

1) I don't know how to define material orientations successfully. I have seen many forum questions about this issue. I cannot define material properties as in Optistruct (2d - composite - material properties - define a base vector). In property type10 SH_COMP I have defined the vector which should be the 0º direction. Is this correct? It doesn't seem to be correct when I try to visualize it with the option 'Composite Layers with Fiber Directions'.

image.png.a2196d02613c1f84e15627d0548428b7.png

2) Error 495 shows up when I run CHECK option.

- Material law25 COMPSH is defined.

- Property type10 SH_COMP is defined.

- In the reference guide says this pair should have compatibility.

Thanks in advance.

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Altair Forum User

This message shows up when this error occurs:

** ERROR IN PROPERTY
DESCRIPTION :
-- PROPERTY ID : 1
-- PROPERTY TITLE : sh_comp
-- MATERIAL ID : 1
-- MATERIAL TITLE : carbon fiber
INCONSISTENCY BETWEEN GLOBAL INTEGRATION AND MATERIAL LAW TYPE=25

Altair Forum User

Hi,

Did you assign thickness in the property card?. If not, please assign and try running again.

If the issue persist please share the model file through the secure dropbox.

Altair Forum User

Hi @George P Johnson,

Do I have to assign the total thickness? I mean, imagine I have a surface with two plies and a laminate (same as I would do with Optistruct) and each ply is 0.21 thick. Do I have to enter 0.21 or 0.42?

Is it ok to leave the other parameters in blank?

Thanks

Altair Forum User

Hi,

You have to assign the total shell thickness, ie in this case 0.42. Please assign this and try running.

Altair Forum User

Hi,

Thanks, that seems to work.

In relation with question 1). Do you know how can I define material orientation?

Altair Forum User

Hi,

For /PROP/TYPE10, the material orientation is updated based on the vector base node and end node selected by the user.

And it seems to be fine in your property card. If still you find wrong in material orientation please share the file so that we can review.

Altair Forum User

Hi,

You have to assign the total shell thickness, ie in this case 0.42. Please assign this and try running.

Hi,

What if it has different thickness around the model? I have assigned different ply dimensions for each

Altair Forum User

Hi,

For a component when you use /PROP/TYPE10 card use the total thickness of the plies used to model that component.

For different components you have to assign different property cards.

Altair Forum User

Hi,

But what if I have different thicknesses on the same component? Imagine: at a height of 2mm there are four two of, at a height of 4mm there are four plies and at a height of 6mm there are six plies of carbon fiber.

And what happens if I put a different thickness when creating a ply by error?

Altair Forum User

Hi,

In such a case you can try with ply and stack approach.

I recommend you to go through the Help Menu on composite modelling where the modelling approaches with materials and properties are discussed.

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

Altair Forum User

Hi,

Thanks, I understand that with RADIOSS 2017 I can only use thick shell property, and it's quite confusing.

I have read that there is a new property PCOMPP as in optistruct!!! Is it true? Which version do I have to download to be able to use this property? I believe that with this property I won't have this problem.

Thanks

Altair Forum User

Hi,

This property card is not yet supported in HyperMesh. Mostly in the next release this card will be included.

Altair Forum User

Hi,

I have created many properties PROP/PLY for each ply and a property PROP/STACK for the hole laminate.

The PROP/PLY doesn't let me choose the elements to refer the ply... Do you know how can I do it?

Altair Forum User

Sorry @George P Johnson,

I have another problem with time step, I think. Error starts to increase and remaining time increases aswell, so the simulation is instable. I am using /DT_NODA/CST with Tsca=0.9 and Tmin=1e-7.

image.png.25d29359f0bab10ac9635dfa4bca3a41.png

I have tried also to change Tscale to another values in orther to achieve a smaller time step, but it doesn't work. The simulation always fails. How can I choose a correct time step for a simulation?

Altair Forum User

Hi,

The PROP/PLY doesn't let me choose the elements to refer the ply... Do you know how can I do it?

From the ply creation card you have the option to select the elements. What error you are getting when you try to select the elements?.

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

Regarding the time step query:

The best practice to follow while choosing the Tmin, that is the target time step is the mass error of the model should be less than 5% (0.05). From the engine out you can monitor the mass error.

Put the Tsca as 0.9 and choose the target time step by reviewing the initial time step of the model from the starter out file. Please go through https://altairuniversity.com/learning-library/considerations-about-time-step/ which is a webinar showing time step calculation in RADIOSS.

If the simulation still fails, then please upload the starter and engine out (_0000.out and _0001.out) files.

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

Altair Forum User

Hi @George P Johnson,

There are some cases where the simulation runs, and others doesn't. This are starter and engine out files from a simulation that doesn't work right... I have tried with different time step combinations, but it always fails.

Unable to find an attachment - read this blog

Altair Forum User

Hi,

The starter out seems fine, but please check for any incompatible kinematic conditions in the model.In the engine out you can notice that the energy error also rises to 99% and incompatible kinematic conditions can be a cause.

Please check the final animation file generated. And check if the component has a weird behavior.

Altair Forum User

Hi,
I have changed boundary conditions until not having any warning. Still doesn't work...

Altair Forum User

Hi,

Can you please share the model file so that we can review the same.

Altair Forum User

Hi,

I have shared the .hm file in your secure file dropbox.

Thanks

Altair Forum User

Hi,

I have mailed my observations with the model shared.

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