Number of layers in 3D

[kulandaivel_palanisamy]

Hai All,

For a similar part, i made 3D meshing using 4 layers and 6 layers. I found the results are varying slightly between the two.
Please suggest me, whether to do analysis with 4 layers or 6 layers or still on the higher side?

Thanks in advance.
JK

[nordhb]

Hi,
a tetrahedral mesh used for 3D Fill+Pack analysis typically has six or more layers of tetrahedral elements.
So, 6 layers of tetra elements are normally ok.
Then, 8 layers better for fiber orientation 3D analysis.

Regards,
Berndt

[BobSherman5561]

G'day Gentlemen,

In general I try to utilize 12 elements through the thickness when working with fiber reinforced materials, depending upon what you are doing with the analysis. The minimum that I consider usually is 10 elements. After all in the finite difference codes (Fusion and midplane), I always utilized the full 20 laminates when analyzing fiber reinforced materials. You might be surprised what you might miss with too few elements. If you're only doing a fill/pack analysis and not warp or stress analysis with the results, then 6 or 8 might get you by to predict pressures, etc.

Bob Sherman
Sr. CAE Analyst, RTP Company

[kulandaivel_palanisamy]

Thanks to Berndt and Bob Sherman.

Using 20 laminates will sure increase the number of elements and analysis time.
What is the maximum number of elements (in general) you project for 3D analysis . can i know your system specifications in turn to run these?
I am using Windows XP 64 bit, Intel (R) Xeon (R) CPU, 2.26 GHz, 12 GB RAM.

Thanks and Regards
JK

[BobSherman5561]

G'day JK,

I would NOT recommend 20 elements through the thickness in 3D unless you're dealing with very large thickness parts. For the most part in 3D the maximum I have used in 3D, is 12. I only use 20 laminates in Fusion and Mid-plane. To keep the 3D element aspect raitos to reasonable levels, if you went 20 elements through the thickness you would have to drive the element size so small that you will be talking millions of elements for the model, how many millions will depend upon what size parts you are talking about and the part thicknesses.

With your machine I would guess that a 2 million element model in 3D, F/P/W would probably take 24 hours, but you didn't indicate how many processors you have. If you don't have a multiple processor machine, it actually might be longer, but these are guesses. I would recommend you trying different levels of elements thru the thickness and determine what is needed for your level of analysis, because it will depend a lot on what you are trying to solve for with the program. As UI indicated before, if your only looking to find weld lines and pressure, number of gates needed, etc., then 6 or 8 elements in the thickness may be adequate for you.

Bob Sherman
Sr. CAE Analyst, RTP Company