Practical use of statistically modified laminate model for injection moldings

Injection molded fiber reinforced materials offer designers the opportunity to reduce part count in a wide range of consumer products. However, flow induced orientation of the fiber results in anisotropy of material properties, and can lead to concerns regarding stiffness and warpage. In previous work the authors introduced a method for predicting anisotropic stiffness, and evaluating warpage, for this class of materials using empirical data derived from tests performed under conditions close to those used in manufacturing. In this paper the method is used to predict with a high degree of accuracy the variation in bending stiffness within a corner injected plate. It is also used to illustrate sensitivity in linear and buckling warpage modes, and show how small changes in process conditions can completely change the predicted warpage pattern.