Orientation Tab
Define how the fibers should be oriented in the domain. Two possible orientations of the fibers in the XY-plane can be selected from the pull-down menu: Anisotropy or Angle Distribution. Refer to the FiberGeo chapter for a detailed explanation of anisotropy and fiber orientation in the structure’s geometry.
Orientation in Plane: Anisotropy
Selecting Anisotropy, the desired Anisotropy in Plane value can be entered.
A value of 1 for Anisotropy in Plane corresponds to the isotropic case. In the following examples, all other parameters are left unchanged while the value of the Anisotropy in Plane is modified as indicated. For larger anisotropy values the fibers are oriented in Y-direction and for smaller values the fibers are oriented in X-direction.
It is possible to create paper structures with different fiber types which additionally have different values for their Anisotropy in Plane. The following paper structure (500x500x200) of grammage 20 g/m2 was created using 70% of 200 µm long yellow cellulose fibers (25 µm x 10 µm, wall thickness 4 µm) with anisotropy in plane of 200, and 30% of 100 µm long gray elliptical fibers (8 µm x 2 µm) with anisotropy in plane of 1.
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Orientation in Plane: Angle Distribution
After selecting Angle Distribution from the Orientation in Plane pull-down menu, the desired Orientation Angle of the fibers in the XY plane can be directly set to a Constant value or to follow a distribution (Uniformly in interval, Gaussian, Probability Distribution, or Log-Normal) through the Edit... button.
In the following examples, all parameters of the randomly curved circular fibers are left unchanged while the value of the Orientation Angle is modified as indicated.
- Fibers have a constant orientation angle of 30°.
- Fibers have an orientation between 45° and 135°.
- Fibers are normally distributed around the mean value 45° with a standard deviation of 10°.
- The majority of fibers (60%) have an orientation angle of 0°, 20% have 90° angle and another 20% have a 45° angle.
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Rotation Angle
The Rotation Angle is a measure of the angle the fiber profile has to the XY-plane (i.e. a measure for the rotation of the cross-section). This parameter has no effect if the fibers are circular and straight.
The rotation angle can be set to take a Constant value or a distribution (Uniformly in interval, Gaussian, Probability Distribution, or Log-Normal).
In the following example, all parameters are left unchanged (including Random Seed) while the Rotation Angle of the elliptical straight fibers is set as indicated.
The generated structures are shown in 3D Rendering and in 2D Cross-section. The choice of Anisotropy in Plane leads to positively and negatively oriented fibers, so that they appear tilted with +45° and -45°.
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