Abstract

Three-dimensional (3D) reinforcement by stitching is effective in improving the impact resistance of composites. Stitching, however, adversely affects the composite's in-plane mechanical responses, and alters its damage mechanisms due to stitch-induced irregularities. We experimentally investigate the effect of two important stitch parameters, stitch density and thread diameter, on the damage characteristics of 3D stitched multidirectional composites under in-plane tension using X-ray radiography, X-ray micro-computed tomography and digital image correlation (DIC). Our study shows that composites stitched with thicker thread exhibit improved tensile strength due to effective hindrance of edge-delamination. We also found that stitch thread affects damage behaviors. A higher number of transverse cracks develops in the middle portion of thin 90° fiber tows; the inter-crack distance is reduced by dense stitching. DIC is able to identify the cracks that appear in resin-rich channels and distinguish strain fields due to different stitch densities.

Department(s)

Mechanical and Aerospace Engineering

Publication Status

Full Text Access

Comments

King Abdullah University of Science and Technology, Grant ANMC-21

Keywords and Phrases

A. 3-Dimensional reinforcement; A. Polymer-matrix composites (PMCs); B. Delamination; B. Transverse cracking

International Standard Serial Number (ISSN)

1359-835X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

01 Jan 2015

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