| Textile preforms undergo different deformations during preforming including transverse compression, biaxial tensile, in-plane shear and out-of-plane bending deformation. All these deformations change the tow and resin channel geometry of the preform and consequently affect the mechanical properties of the final product. To make simulation tools and to execute structural analysis, accurate experimental data during these deformations is required.In the present work, an in-situ measurement technique has been developed to study the deformation behaviour of textile preforms at meso-scale during the compression mode. This technique for the first time, enables measurement of the meso-structure of dry and wet fabrics under in-situ loadings. Tow geometry changes of single layer and multilayer preforms have been captured under in-situ loadings using computed tomography (CT). Resin channels in single layer and multilayer preforms have been investigated in detail. In multilayer fabrics, it has been observed that nesting of the layers strongly influences the inter-tow voids. It has been observed that crimp reduction in single layer fabric and nesting of layers in multilayer fabric is responsible for the fabric thickness reduction in a low load regime (~100 kPa).During study of different fabric architectures, it has been observed that the float length of the weave plays an important role in compression behaviour. The deformation of wet fabrics has also been studied at macro and meso-levels using mechanical test results and CT. It has also been observed that at low loads (~300 kPa) there is higher crimp reduction in wet fabrics compared to dry fabrics.Additionally, an in-situ measurement technique has also been developed to study the meso-structure of dry fabrics under biaxial tensile and shear loading using CT. |
