THE EFFECT OF SHEAR DEFORMATION ON THE PROCESSING AND MECHANICAL-PROPERTIES OF ALIGNED REINFORCEMENTS

The growth of liquid moulding processes for the production of structur al and semi-structural components has been eased by the development of computer-aided engineering tools for structural analysis and process modelling. However, the accuracy of these roofs is dependent on the av ailable material property data. These are usually obtained from experi mental or theoretical analysis of flat plaques. These methods do not t ake into account reinforcement deformation during the preforming proce ss. Deformation, caused by forming two-dimensional reinforcements over three-dimensional surfaces, can result in local fibre reorientations and volume fraction changes within the preform. In this study the majo r deformation mode, simple shear, is isolated. The effects of simple s hear deformation on permeability and elastic properties of engineered and woven glass fabrics are investigated. Predictions of elastic prope rties are made by using established methods and compared with experime ntal data for a range of fabric architectures. A semi-empirical method is applied to characterise the effects of shear on reinforcement perm eability. (C) 1997 Elsevier Science Limited.