AN IMPROVED METHOD TO CHARACTERISE TOW GEOMETRY AND STRESS-STRAIN RELATION OF TEXTILE COMPOSITE PREFORMS DURING SHEAR DEFORMATION

摘要

This paper presents an improved method for measuring the in-plane shear behaviour of biaxial textile preforms. Of the current methods, bias extension is the easiest to perform; however, this method suffers from tow slippage at modest shear angles. In the improved method, a fabric sample wider than the clamps has been used in order to eliminate tow slippage and maintain the pure shear region as a complete rhombus. The tow geometry has been frozen with the help of a simple clamping arrangement. Tow details have been measured from the cross-sectional images of impregnated samples. Preliminary findings from stereo-imaging of dry fabrics have also been presented.