PSI - Issue 19

Marc J.W. Kanters et al. / Procedia Structural Integrity 19 (2019) 698–710 Marc Kanters et al. / Structural Integrity Procedia 00 (2019) 000–000

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3. Numerical methods 3.1. Workflow

For accurate modeling of the mechanical performance of parts made from SFRP the so-called integrative approach is employed, meaning the effects of the injection moulding process are included. This requires combining different software tools (see Figure 2): I) injection moulding simulation software to predict the orientation of the glass fibers (Autodesk Moldflow, version 2019), II) material modelling software tools (Digimat, version 2019.0), III) a FE code (Abaqus, version 2018) to simulate the mechanical part performance, and IV) an interface to compute lifetime. The material modelling software package Digimat provides: material model calibration, interface of the material model to the FE code (in our case Abaqus), mapping of the glass fiber orientation from the Moldflow mesh to the Abaqus mesh, and the lifetime computations.

Figure 2: Overview of the numerical workflow.

3.2. Digimat Composites are, by definition, a combination of two or more constituents to obtain an improved material performance in comparison to the base constituents. As composite properties depend on the material microstructure, including fiber amount, aspect ratio, and orientation, they can be modeled from micromechanical approaches that include the fully resolved microstructure. Such approaches are numerically expensive and therefore mean-field homogenization techniques have been developed that combine the properties of the underlying constituents of a multi phase material so that the original heterogeneous material is represented by an equivalent homogeneous one (see Figure 3). This technology has proven effective for a broad range of materials and is implemented in the Digimat software [e-Xstream2019].

Figure 3: Heterogeneous material (left), the micro-structure represented by pseudo-grains with fixed orientation (middle), and the homogenized material model from the two-step homogenization (right), taken from [e-Xstream2019]