Fiber Orientation XML Output - Diagonal Sum is Greater than 1

[amac441]

Hello. 

I am trying to interpret the results of a fiber orientation simulation.  I get the following tensor XML output, but have a few questions. 

<HEADER>
<NAME> Moldflow Simulation Results XML Writer</NAME>
<Version> 1.00</Version>
</HEADER>
<Dataset Name="Fiber orientation tensor eigenvector" ID="4008">
<DataType> ELDT(Element data)</DataType>
<DeptVar Name="Fiber orientation tensor eigenvector (3D)" Unit=""/>
<NumberOfComponents> 6</NumberOfComponents>
<NumberOfIndpVariables> 0</NumberOfIndpVariables>
<Blocks>
<NumberOfBlocks> 1</NumberOfBlocks>
<Block Index="1">
<NumberOfDependentVariables> 221225</NumberOfDependentVariables>
<Data>
<ElementData ID="87189">
<DeptValues> -7.8423e-002 4.9759e-004 9.9692e-001 -2.3132e-001 9.7270e-001 -1.8682e-002</DeptValues>
</ElementData>

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.

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My questions:  

1. The documentation says I should only get 5 values output, but I am seeing 6.  

(See here:

http://forums.autodesk.com/autodesk/attachments/autodesk/366/4649/1/AMI_Fiber_orientation_analysis.p...   

The original nine components reduce to five independent components)

2. Regardless, given the 6 values, am I correct in assuming that the tensor represents the following 3x3 matrix  

-7.8423e-002     -2.3132e-001     9.7270e-001

-2.3132e-001     4.9759e-004      -1.8682e-002

9.7270e-001     -1.8682e-002      9.9692e-001

3. If number 2 is correct, why is my diagonal not = to 1

-7.8423e-002+4.9759e-004+9.9692e-001 = 0.91899459

Thanks,

AJ

www.multimechanics.com

[jinwang]

Read the XML header, the six numbers are components of the eigenvectors of the fiber orientation tensor corresponding to the two largest eigenvalues.

You need to find the XML file containing the orientation tensor results (ID = 4021 for nodal results or ID = 4009 for elemental results). Moldflow outputs 6 components of the orientation tensor in such order: A11, A22, A33, A12, A13, and A23.

Regards,

Jin Wang

[jl13215]

I understand what eigenvectors are, but why would you want to output Fibre orientation Tensor eigenvectors?