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# Fiber orientation tensor result

The Fiber orientation tensor result shows the orientation tensor (degree of orientation) at the end of the injection molding process.

This result is generated by a Fiber orientation analysis.

## Using this result

Using Midplane or Dual Domain analysis technology, the Fiber orientation analysis calculates the layer-based fiber orientation tensor at each time-step throughout the Fiber orientation analysis. Using 3D analysis technology, the Fiber orientation analysis creates nodal and elemental fiber orientation tensor results. This tensor is symmetric, thus it is expressed with six components in each laminate of each shell element of a Midplane or Dual Domain mesh model, or at each node and on each tetrahedral element in a 3D mesh model.

The fiber orientation tensor output is the fiber orientation tensor result at the end of the injection molding process.

The Fiber orientation tensor result shows the probability of fiber alignment in the specified principal direction. A high probability of fiber alignment in the specified principal direction will be indicated by a value of close to 1 on the result scale, whereas a low probability is indicated by a value close to 0. The fiber orientation tensor in the first principal direction is the most useful result to view.

NoteThe first principal direction is close to the material flow direction in most cases, but it may not always coincide with the flow direction.

The fiber orientation tensor is expressed in the global coordinate system, and is also used to calculate the mechanical/thermal property as well as the residual stress in the cavity.

The diagonal components of a fiber orientation tensor represent the strength of alignment in the respective directions. The values of diagonal components range between 0 and 1, and the sum of all three diagonal components is 1. The off-diagonal components of a fiber orientation tensor represent the amount that alignments vary from the coordinate axes, and they are zero when coordinate axes coincide with the principal directions of the orientation tensor.

The principal directions are numbered in the order of the respective principal values, from the largest to the smallest. The first principal direction represents the direction along which the most fibers are aligned, and the third principal direction represents the one along which the fewest fiber are aligned. The larger the principle value is, the stronger the alignment in the corresponding principal direction is.

TipTo more easily interpret fiber orientation results, it is recommended to check principal values or tensor components as well as principal directions. Right-click the result name in the Study Tasks pane and select Properties:
• Select the Methods tab to change the result display method. The default Tensor as axes display method and other tensor display method options plot both value and principal direction results. The Shaded and Contour display methods plot only value results.
• Select the Tensor tab to change the tensor principal value (direction) and tensor component displayed on the model.
ImportantUsing 3D analysis technology, the default Fiber orientation tensor result displayed is based on nodal data. Using nodal data improves the display of the fiber orientation profile through the thickness of the part. This is most easily seen when the Fiber orientation tensor result is displayed using the plot type Probe XY plot. This result based on elemental data is still created, but it is not displayed by default. To display it, click Results tab Plots panel New Plot and select Fiber orientation tensor on elements from the list of available results.

## Things to look for

• The fiber orientation tensor result provides the final results of fiber orientation, at the end of the analysis.
• Inconsistent alignment/orientation of fibers. There should be a high probability of fiber alignment in the first principal direction.