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The FFF manufacturing method allows the characteristics that one direction of the material (build direction) has a significant lower stress threshold. Because of this, Isotropic material behaviour can be combined with the FFF Thumb Rule Failure Criterion to define the maximum stresses for the build direction and for the in-plane directions easily with one scalable value.
While using 3D Transversely Isotropic and 3D Orthotropic materials even more adjustable material limits can be set up like a difference between tension and compression strength besides the directional dependency (Tsai-Wu).
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