Non-isothermal three-dimensional developments and process modeling of composites: Flow/thermal/cure formulations and experimental validations

In the process modeling via Resin Transfer Molding (RTM) for thick composite sections, multi-layer preforms with varying thermophysical characteristics across the different layers, or for geometrically complex mold geometries with varying thicknesses, the assumption of a thin shell-like geometry is no longer valid. The flow in the through thickness direction is no longer negligible and current practices of treating the continuously moving flow front as two-dimensional and the temperature and cure as three-dimensional are not representative of the underlying physics. In view of these considerations, in the present study, the focus is on the non-isothermal process modeling of composites employing full three-dimensional modeling/analysis developments via effective computational techniques. The specific applications are for thick composite geometries where the thickness is comparable to the other dimensions of the part. For the first time, an implicit pure finite element front tracking technique is employed for the transient flow/thermal/cure coupled behavior of the full three-dimensional modeling of the moving boundary value problem, and, due to the highly advective nature of the non-isothermal conditions involving thermal and polymerization reactions, special considerations and stabilization techniques are proposed. Validations and comparisons with available experimental results are particularly emphasized and demonstrated.