The influence of through-thickness reinforcement geometry and pattern on delamination of fiber-reinforced composites: Part II - Modeling

Published on Dec 1, 2017in Composite Structures5.138
· DOI :10.1016/J.COMPSTRUCT.2017.08.096
G. Pappas8
Estimated H-index: 8
(EPFL: École Polytechnique Fédérale de Lausanne),
Simon Joncas10
Estimated H-index: 10
(École de technologie supérieure)
+ 1 AuthorsJohn Botsis37
Estimated H-index: 37
(EPFL: École Polytechnique Fédérale de Lausanne)
Sources
Abstract
Abstract This article reports modeling techniques and results based on experimental Mode I characterization of a layered woven GFRP material with tufting reinforcement. Standard tuft and loop-less geometries are investigated on three different areal patterns to evaluate their effects on fracture resistance. The experiments reveal that tow/ply and tuft bridging phenomena are present during delamination. The numerical modeling comprises cohesive elements for tow/ply bridging and 1D connector elements for discrete tufts. The traction separation relations for the cohesive model are acquired using an inverse scheme based on strain measurements and the force-separation relations of tuft’s failure mechanisms from uniaxial pulling tests on a reference tufting pattern. Results show that tuft’s failure mechanism is strongly affected by tufting pattern and geometry while tow/ply bridging contributes 20–30% of the overall fracture energy. The energy absorbed by pull-out of loop-less tufts is approximately twice the fracture energy of standard ones with pull-out triggering much more extensive tow/ply bridging phenomena.
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