Engineering and Computer Science Faculty Publications

Title

Effect of Notch on Failure of Two-Dimensional ±45° Triaxial Braided Textile Composite Materials

Document Type

Article

Publication Date

7-1994

Journal Title

Journal of Composites Technology and Research

Volume

16

Issue

3

First Page

262

Last Page

269

DOI

10.1520/CTR10415J

Abstract

The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2-D) triaxial braided composites are examined. The effects of notch size and notch position within the macroscopically nonhomogeneous textile material are investigated. Damage initiation and propagation in notched and unnotched coupons are also examined. Two different fiber architectures are considered, both of similar braid geometry but one with larger longitudinal yarns (approximately six times) and larger percent of longitudinal yarns (approximately four times). The 2-D braided coupons exhibited notch and notch position sensitivity that were architecture dependent. Notch sensitivity occurred in coupons with notch size greater than the unit cell size and increased with hole diameter. Results suggested notch position sensitivity in one of the architectures tested. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and to propagate in the direction of the braider yarns until failure. Fracture occurred along the braider yarn in both architectures but differed in size and appearance, suggesting architectural influences on damage mechanisms. Our results show the damage initiation and propagation is most likely to occur within the braider yarns.