New remeshing applications in resin transfer molding

As resin transfer molding (RTM) is being increasingly used to manufacture composite parts, there is a strong interest to understand the basic physical phenomena that occur at each stage of the process. Modeling and simulation play an important role in the development and optimization of molds production and in devising appropriate resin injection strategies. In general, process simulation requires preprocessing to be carried out carefully to conduct successful, reliable, and reasonably fast calculations. However, it can be time consuming at the early stages of mold design to run several simulations with minor changes only in the geometrical model or in the mesh in order to optimize the mold or some given operating conditions. Unfortunately, in that case the entire mesh has usually to be regenerated. This paper presents applications of a remeshing algorithm to RTM flow simulation. It illustrates how remeshing techniques can be used to enhance the automatic meshing capability by including injection ports and channels along the mold boundaries or along the interior injection lines. Remeshing can also be used to smooth the resin front during mold filling. In the latter case, mesh refinement is based on the flow front without attempting to minimize computational error. By adapting the mesh anisotropy to the flow front during mold filling, the shape of the advancing flow front can be more closely approximated. The first part of this paper describes the remeshing algorithm and the associated anisotropic metric. Then, several examples of metrics are given to provide guidelines for application engineers and also to illustrate their practical implementation. After introducing the RTM process and recalling the basic equations that govern mold filling, local remeshing of injection ports and runners are presented, followed by the application that minimizes front smearing.