MODELING MATRIX INJECTION THROUGH ELASTIC POROUS PREFORMS

This study deduces a new model aimed at simulating injection moulding processes under isothermal conditions and in situations in which infil tration generates deformations in the reinforcing network, both in the solid preform part which is still dry and in the part that has alread y been infiltrated. As a by-product the model allows the stress and de formation states in the solid preform to be monitored. The coupled flo w/deformation problem in the fully infiltrated region and in the uninf iltrated region is then formulated with the proper evolution equations for the boundaries delimiting the two domains and with the relative b oundary and interface conditions. The stationary configurations for th e one-dimensional problems characterized by given infiltration velocit y or pressure are analytically determined for general elastic stress-s train and permeability-volume ratio relations. The unsteady problem is solved numerically, putting in evidence the influence of the deformat ions on the bulk flow and on the propagation of the advancing front. ( C) 1997 Elsevier Science Limited.