A multi-step biaxial bias extension test for wrinkling/de-wrinkling characterization of woven fabrics: Towards optimum forming design guidelines

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): A. Rashidi, A.S. Milani
Wrinkling is one of the most common flaws taking place during the forming process of textile composites with complex mould geometries. It is of importance to designers to be able to predict the minimum amount of forces that are required to diminish the wrinkles in useful regions of the final product, through applying appropriate boundary conditions enforced at the blank holders. Towards this goal, herein a multi-step biaxial bias extension (MBBE) characterization test has been proposed to assess the magnitude of the required transverse de-wrinkling forces that can smooth out wrinkles of different sizes, formed at different shear angles of a plain weave fabric. Employing image processing and 3D scanning during the MBBE test, the local shear angles and dimensions of wrinkles were characterized and correlated to the measured forces. It was shown that applying excessive transverse loads to yarns can result in a very narrow formability window and eventually cause fiber breakage, hence suggesting critical role of forming optimization, given different part shapes and fabric types.

Graphical abstract

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