Caractérisation expérimentale des préformes 3D en fibres de carbone assemblées à l’aide du procédé de couture « One Sided Stitching » dédiées à la fabrication des pieces composites aéronautiques

Abstract

This work aims at investigating the effect of structural stitching of carbon fibre preform realised using the technique of one-sided stitching, on the mechanical behaviour of dry preforms. In contrast to studies on woven or braided preforms, the stitched preforms were not so widely covered so far. The stitching technique used in this study is considered as rapid process of preform preparation in which yarns or layers are arranged along selected directions in the plane and then tied together along predefined paths using a sewing needle. These through the thickness stitched carbon fibers preforms are developed and optimized for use in the manufacture of composite structures for aeronautical applications. It has been demonstrated that many 3D textile fabrics, especially stitched preforms, have a high potential for lower cost manufacturing and high performance of final composite structures with good damage tolerance and structural integrity (Ogale, 2007). When comparing studies carried out on the same reinforcements, sometimes it seems that contradictions appear; some studies claim that the stitching process does not affect or can slightly improve the properties in the plane, while others reveal that the properties are degraded by a needle that creates slight deviations and breaks the threads. The technology used for producing the carbon fibre preforms is discussed along with salient results obtained from mechanical testing under compaction, in-plane shear and bending. Tests were conducted on unstitched preforms and preforms stitched using different parameters including stitch density and stitch pattern. It was demonstrated that the stitching configurations and densities affect compaction behavior of preforms leading to a decrease in fibre volume fraction. From shear and bending tests, it was found that stitching shows minimal effect on the response of stitched preforms comparing to unstitched fabrics. This behavior under shear and bending loading contributes the preforms the ability to comply with complex shapes such as T stringers that were manufactured in the framework of the CRIAQ COMP-501 project.

Date	5 Jun 2018
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Simon Joncas (Supervisor) & Francois Robitaille (Co-supervisor)