Constitutive modeling of injection‐molded short‐fiber composites: Characterization and model application

Abstract

AbstractA previously developed constitutive model for short‐fiber reinforced thermoplastics is applied to an injection‐molded component with a complex geometry and microstructure. This macro‐scale continuum‐based model is able to capture the anisotropic viscoelastic‐viscoplastic response of the material. In injection‐molded short‐fiber composites, the anisotropic mechanical properties depend strongly on the fiber orientation distribution, which generally displays a marked variation throughout the product. This makes the material characterization and model application challenging. In this article, two characterization and model application strategies are proposed. These techniques, together with the developed constitutive model provide a strong tool for reliable prediction of the mechanical response of an injection molded product, where inputs to the finite element analysis are obtained directly from a numerical simulation of the injection molding process. In this article, from the output provided by an injection molding process simulation software such as Moldflow, the distribution of anisotropic elastic and plastic properties throughout the component is found and the data is imported to the finite element mesh. Mechanical tests are performed on a validation product and results are compared with model predictions from finite element simulations. Through this comparison, the performance of the constitutive model and also proposed procedures for characterization and model application are investigated.