Study of the ultrasonic compaction process of composite laminates—part II: advanced numerical simulation

The ultrasonic compaction might be a suitable technique to obtain well compacted composite laminates in order to implement them in out-of-autoclave automated curing processes. This procedure generates an ultrasonic vibration over the laminate that makes the resin heat and allows the composite plies to be compacted. The numerical study of this heat generation and its distribution within the laminate requires the modelling of the resin and the fibre layers separately, requiring a very fine mesh. Furthermore, the process needs a discretization along the time with very short time steps, in order to model the ultrasonic vibration properly. For these reasons, a fine FEM solution is very costly to compute. Space-time separated representations as the ones considered in Proper Generalized Decomposition (PGD) techniques seem to be an appealing choice for addressing the solution of ultrasonic compaction thermomechanical models. In this work, the formulation and implementation of a PGD solution of a model for the viscous heating and temperature distribution during the compaction of composite layers is presented. The compaction will be studied in two operating modes: it will be studied as a transient problem, assuming that the compactor is still over the laminate and as a steady-state problem, assuming that the compactor is moving along the laminate. Finally, the solution obtained with the transient model will be compared with experimental measurements, showing that the model predicts the behavior of the temperature inside the laminate properly.