Characterisation of reinforcement fabrics by fractal dimension

During lamination of fibre-reinforced polymer matrix composites, there is a potential risk that the operator may use fabric from the wrong roll. This could severely change the desired mechanical properties of the component. This paper presents a novel system that might be implemented within a quality system to ensure use of the correct fabric. Three carbon fibre reinforcement fabrics (300 gsm plain weave, 320 gsm single-tow twill and 375 gsm double-two twill) were characterised. Images were acquired using a high-resolution scanner, converted into binary, then analysed using ImageJ/Fraclac software. The slope of the Richardson Plot is the Fractal Dimension (FD). The three fabrics each had a distinct FD value, in the undeformed condition and when sheared up to 30° (the locking angle).