Composite material modeling 3

[janipk]

I am new to composite engineering and wanted to model a composite material with following information:

Ply thickness= 0.127 mm

6-6-6-6 Layup(+45, -45, 90, 0|S)

here 'S' stands for symmetry.

I am using MSC Patran for modeling and Nastran for analysis.
Could anyone help me how to fill this information in Patran?

Thanks in advance!

 

[RPstress]

6-6-6-6??

Patran's method for making Nastran's PCOMPs (probably what you want) is slightly couterintuitive. It's under Material-> Create / Composite / Laminate .

First you need to do Material-> Create / 2D orthotropic to enter the ply properties which are referenced in the laminate.

Finally you need to do Properties-> Create / 2D / Shell with Option Laminate .

I have to say this isn't really the place for instruction in basic use of a specific pre-proecssor. All this stuff should be available in the online help, albeit with a bit of rooting around.

 

[janipk]

Hi RPstress,

I am sorry to say that all the stuff you have said is already known to me also. I think, I could not make my question very clear.

1. 6-6-6-6 means: 6-pleis at 45°, 6-plies at -45°, 6-plies at 90° and 6-plies at 0° are oriented.

2.My question was about the (45°,-45°,90°, 0°|3S), what does it mean?
Is it mean all 24 plies are orientated like:
45°,-45°,90°, 0, 45°,-45°,90°, 0, 45°,-45°,90°, 0, 45°,-45°,90°, 0, 45°,-45°,90°, 0, 45°,-45°,90°, 0

OR
something else?

I know when you have simple 24-plies with 24 orientation angles, it should be fill in Patran (with Total option checked) like above given order but now I have just 4-orientaions.

3.How to use the Symmetry option in this particular case with (45°,-45°,90°, 0°|3S)? NOTE:3S

 

[rstupplebeen]

45°,-45°,90°, 0°, 45°,-45°,90°, 0°, 45°,-45°,90°, 0°, 0°, 90°, -45°, 45° , 0°, 90°, -45°, 45° , 0°, 90°, -45°, 45°

 

[janipk]

Hi rstupplebeen,

Thanks a lot man!

Wish you a nice evening.

janipk

 

[RPstress]

Agree with rstupplebeen. You shouldn't block together too many plies. If you have more than a mm all at the same orientation you will get cracking.

You can enter half the laminate [45°,-45°,90°,0°,45°,-45°,90°,0°,45°,-45°,90°,0°] and use the symmetry option.

 

[Hansmeister]

janipk,

Your laminate stack is not OK since there is no mid-plane symmetry. The layup defined by rstupplebeen is the correct one. This laminate is usually referred as "quasi-isotropic", or "quasi-iso" for short.

 

[janipk]

Hi to all,

Thanks to all of you for kind remarks

 

[rerig]

janipk,

Check out MIL-HDBK-17-3F, Para: 5.6.5.2, Pg 5-68 for an explaination of design basics for Laminate Stacking Sequence (LSS).
The info given above is correct.
Here is why. (you said you were new)

Rerig