Improvements in the prediction and characterization of the thermoelastic response of glass-fibre reinforced composite products

Significant improvements in the prediction of the thermoelastic constant of SMC (sheet moulding compound) have been made as a result of the use of the iso-stress version of the Young's modul;s of the polyester-limestone matrix (i.e. the ''series'' rule of mixtures version) in place of the iso-strain version (i.e. the ''parallel'' rule of mixtures version). The thermoelastic constants of GMT (glass-mat-reinforced thermoplastic) and RTM (resin-transfer-moulded material) can also be accurately predicted. The property variations in large moulded GMT panels, with nominal glass contents of 20% and 40%, have been studied using the SPATE equipment and a thermoelastic technique has been developed, based on the simple disc specimen subjected to two opposed in-plane compressive forces, for the determination of the principal material directions in these panels. Copyright (C) 1996 Elsevier Science Ltd.