Meaning
Material response characterized by directionally dependent physical properties within a solid body defines this physical state. When short-glass fibers align with the melt flow during injection moulding, anisotropic elasticity develops because the reinforcement provides higher modulus along the fiber axis than across it. This variation limits the use of single-value datasheets for structural predictions in complex geometries.
Fiber Orientation
Molten polymer carrying glass fibers creates local regions of varying stiffness as the orientation follows the cavity velocity profile. Stress applied parallel to these fibers meets higher resistance than stress applied perpendicularly.
Moulding Influence
Gate location and wall thickness dictate the flow front behavior that determines the final distribution of material properties. A thin wall encourages high shear and strong alignment, while a thicker section allows a random core to form between aligned skins. Failure to account for these gradients leads to parts that warp or crack under loads that a standard isotropic model would suggest are safe.
Simulation of the filling process maps these directional vectors onto the structural mesh.
Part Specification
Accuracy in predicting deflection requires calculating the stiffness tensor for every element in the component. Isotropic assumptions usually overestimate the strength of the knit lines where flow fronts meet and fibers fail to cross the interface.
