Effect of Fiber Orientation and Residual Stresses on the Structural Performance of Injection Molded Short-Fiber-Reinforced Components

To optimize the strength design of short-fiber injection molding components, a three-dimensional flow and structural analysis simulations were employed. In particular, these Finite Element Analyses (FEA) were based on orthotropic, linear and elastic models including process-induced residual stresses. Through an appropriate interface, the results of injection molding analysis of 35 wt.% fiber reinforced polyphthalamides (PPA) manifold block used in hot-water fluid engineering application are transferred to the structural analysis software. In particular, Autodesk Moldlfow software was used to predict the fiber orientation and the in-cavity residual stresses considering the flow kinetics and moulding parameters. The Abaqus interface for Moldflow was used to translate this data into a form that can be used for the structural analysis. Experimental tests were carried out on the injection moulded component in order to evaluate the internal burst pressure values. The burst strength of the component was then compared with those predicted by the numerical analysis. The computations are found in good agreement with the experimental results.