Long fiber - moldflow analysis

[madhukeshwart]

I have heard moldflow software  is designed for short fiber analysiis only and it assumes ,  that fibers wil be short when reaches the part,

Is it true?  If i'm wrong please do correct me .............

[JCourter]

Hello Madhukeshwart,

In the current released builds of Moldflow that is correct.  We utilize the Folgar-Tucker model for orientation calculations, and it was developed based on observations of short fiber composites and is not adequate for long fiber composites.  Also of concern is the potential for fiber breakage which is much more common in long fibers than short fiber.

All that said, we currently are working on a new orientation model to account for long fiber composites.  This model isn't currently in release, but we do have an Autodesk Labs release available where this future feature can be tested right now.  All you need is a current Autodesk Moldflow 2011 license, and to use the link below to download and install the labs release, Autodesk Moldflow Radium.

http://labs.autodesk.com/utilities/moldflow_radium

-Justin

[madhukeshwart]

Thanks for your reply.

We have that licence and downloaded the radium technology version.

I think  it is in beta version.

currently we are are working on part, which uses longfiber.

Let us observe the results and how much it wokrs?

I have heard that Ci/Dz and l(lamba), values are most important for fiber oreintation prediction.

what are these and singificance of these parameters?

and that they are calucated automatically by moldflow. Is it same happens with long fiber?

Is those values can be different from materila to materila or process dependent?

Is there any literature avaialble with any one, please do share with me.

Thanks in advance

[Anonymous]

I'd start with Chuck Tucker's original papers on the subject.

ARD Model:  Phelps, J. H. and C. L. Tucker, "An Anisotropic Rotary Diffusion Model for Fiber Orientation in Short- and Long-Fiber Thermoplastics," Journal of Non-Newtonian Fluid Mechanics, 156, 165-176, 2009.

RSC Model: Wang, J., J. O'Gara and C. L. Tucker, "An Objective Model for Slow Orientation Kinetics in Concentrated Fiber Suspensions: Theory and Rheological Evidence," J. Rheology, 52, 1179-1200, 2008.

Most of your questions have not been answered as yet, at least in public.  There is a project at Oak Ridge and Pacific Northwest National Labs to try to answer many of those questions.  I just got finished molding 24" square LGPP plaques for them to analyse.

Pete Foss

GM R&D

[madhukeshwart]

Thanks for all who have replied

[Anonymous]

Hello,

I already install  Autodesk Moldflow Radium, but i dont know what function of this software compare than  Autodesk Moldflow Insight 2011, What situation i should be use for this  Autodesk Moldflow Radium?  email me: azaman@unimap.edu.my

Give me advice, tq

[Anonymous]

Hello,

AMI 2012 is now release. To analyse long fiber:

-Switch to RSC-ARD model if this model is selected AND if fiber length >1mm

-Only a few materials have fiber length, it is the long glass fiber material

-Fiber length is the initial fiber length, we don’t consider breakage

-RSC and ARD are able to run with compressible solver for thermosets (Midplane and DD)

Best regards Stefan

[Anonymous]

Also realize that at this point (someone correct me if I'm wrong), the long fiber beta code is not accounted for in the warpage results.  It is only implemented in the fiber orientation results...for now.

Regards,

Tim

[Anonymous]

As a followup clarification, does 3D warp with fiber orientation calculation on use the inputed CLTE and flow/transverse modulus properties at all?  Or does it all come from the micromechanics models.

Pete Foss

GM R&D

[Shawn_Gedman]

"Also realize that at this point (someone correct me if I'm wrong), the long fiber beta code is not accounted for in the warpage results."

For midplane and dual domain, warp will use the mechanical data calculated during the Flow analysis, and so the modulus for each element (based on long fiber orientationand micro mechanics model) and the residual stress (which are using also the mechanical properties). Note in case of there are CRIMS data, those CRIMS have been calculated based on a long fiber analysis.

3D Warp with fiber orientation uses micro-mechanics and orientation averaging calculated composite properties, including CLTE which is based on Rosen-Hashin model and the stiffness tensor calculated from the micro-mechanics / orientation averaging. The inputted values, if matrix properties are not specified for use, are used for de-composition to get matrix properties.

So yes, we will use the long fiber orientation from flow into warp.

But note, we will not take into account phenomena like :

•             fiber length distribution

•             long fiber composite properties

•             fiber dispersion

PS : I edited the post to have a more complete answer for Pete

[Anonymous]

Thanks, I appreciate the detailed answer.

Pete

[Anonymous]

How do we switch to the RSD-ARD model?

[JCourter]

Please refer to the article below for the procedure of modifying the fiber solver used, specifically to the RSC-ARD model for long fiber calculations;

http://usa.autodesk.com/adsk/servlet/ps/dl/item?id=17766031&linkID=13030537&siteID=123112