Modelling of isothermal consolidation in glass-polypropylene commingled composite

A balanced twill weave commingled fabric was consolidated by an isothermal vacuum forming process. Samples were tested in three point bending and the void content was measured to validate a consolidation model that predicts void content as a function of pressure, time at pressure, and temperature. Sensitivity studies revealed the effect of two parameters - the number of fibre agglomerations and the empirical permeability parameter, used to fit the consolidation model. A microscope image analysis technique was used to investigate the evolution of the microstructure during consolidation and to quantify levels of void content. These measurements were correlated with the mechanical properties of laminates consolidated for a range of times at pressure. It was found that a void content of 10% decreases flexural strength by 50%. (C) 2003 IoM Communications Ltd.