Experimental and numerical analyses of the mechanical behavior during draping of non-orthogonal bi-axial non-crimp fabric composite reinforcements

Experimental analyses and modeling of the draping of composite fiber reinforcements generally concern textiles where the fiber directions are orthogonal in the initial state. However, there also exist biaxial NCF (Non-Crimp Fabric) reinforcements, where the two fiber directions are non-orthogonal. One objective of this paper was to revisit the picture frame and bias extension tests in the case of such non-orthogonal NCFs in order to determine the in-plane shear behavior which is different for positive and negative shear angles. A simulation approach based on stress resultant shell elements was developed for these reinforcements by taking into account the specific plane shear behavior of non-orthogonal NCF reinforcements identified by picture frame tests. It was shown that simulations of non-orthogonal NCF (0-45 degrees and 0/135 degrees) draping processes gave results that were consistent with experimental forming tests of these materials. In particular, the hemispherical forming of an NCF at 0-45 degrees led to a very specific deformed shape with a good correlation between simulation and experiment. Some specificities of the 0-45 degrees pre-forms, especially weak areas, have been highlighted both by simulation and experimentally.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study aimed to investigate the in-plane shear behavior of non-orthogonal NCF reinforcements and revalidate the forming performance of these materials through picture frame and bias extension tests. It was found that the simulation results were consistent with the experimental forming tests, and some specificities of the 0-45 degrees preforms were highlighted.