MODELING THE CONSTITUTIVE RESPONSE OF AN ANISOTROPIC DUAL-SCALE FLOW

Paper in proceeding, 2012

Today’s trend in composites manufacturing is to reduce cost by, among other things, cutting down the number of operations required to produce a component. For example all the steps of impregnation the reinforcement, consolidation, forming and finally curing may be, in some cases, combined into a single processing operation. This leads to increasingly complex manufacturing processes with many interacting sub-processes occurring simultaneously on different spatial and temporal scales. In this context we are developing an unified finite-strain continuum framework [1],[2],[3],[4], which we recently adopted towards modeling of dual-scale flows in composite manufacturing [5]. In this context, in the present work we consider the manufacturing of the so called Engineering Vacuum Channel (EVaC) prepreg materials as discussed in e.g. [6]. Even though our numerical framework is capable of modeling all the interacting sub-processes at ones, the constitutive models for these are still rare and have not been generalized in a proper continuum context. In summary, the idea of the present work is to emanate from the existing model for fluid follow in a rectangular channel (the so called Poiseuille flow) and generalize it in the finite-strain continuum context. The major task is then to extend our framework to account for anisotropic Darcian interaction on the macro scale and implement the constitutive model into it, while the minor task is to examine the interaction between preform deformation on different scales and the process of micro infiltration and macro flow. The major task is accomplished by introducing the anisotropic permeability model to our coupled displacement-pressure, non-linear finite element model, while the minor task is approached using a representative numerical example, displaying the relevant interactions between the involved sub-processes. The algorithm is then tested for drained conditions, and results are compared to the one in [5] for isotropic flow.