Effect of matrix damage on compressive strength in the fiber direction for laminated composites

Published Date
Composites Part A: Applied Science and Manufacturing
March 2017, Vol.94:86–92, doi:10.1016/j.compositesa.2016.12.012

• Author 

• G. Eyer ^a
• O. Montagnier ^a,b,,
• C. Hochard ^a
• J.-P. Charles ^a

• aAix Marseille Univ, CNRS, Centrale Marseille, LMA, Marseille, France
• bCentre de Recherche de l’Armée de l’Air, École de l’air, B.A. 701, 13661 Salon-Air, France

Received 1 May 2016. Revised 2 December 2016. Accepted 10 December 2016. Available online 19 December 2016. 

Abstract 

An original experimental method is proposed to characterize the influence of matrix damage on the compressive strength of laminated composites in the fiber direction using tubes. These composite tubes have a dumbbell-shaped geometry so that rupture occurs in the specimen center without stress concentration. They can be constituted of unidirectional or woven plies aligned with the axial direction. First, a torsional cyclic load is applied in order to damage the matrix. This damage is measured at the tube scale via the reduction in shear modulus. Second, a compressive load is applied up to failure for various damage levels.

The method is applied to a woven carbon/epoxy material. Results show that the matrix damage affects significantly the compressive strength in the fiber direction. It is yet observed that longitudinal stiffness is not modified by damage. Finally, a simple model is proposed to describe this decrease of strength vs. matrix damage.

Keywords

A. Polymer-matrix composites (PMCs)

B. Strength

C. Damage mechanics

D. Mechanical testing

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Nomenclature

matrix damage (–)

longitudinal modulus of the ply (MPa)

shear modulus of the ply (MPa)

shear modulus of the matrix (MPa)

non linear parameter (–)

longitudinal strain (%)

longitudinal stress (MPa)

fiber volume fraction (–)

Subscript

compression

tension

Superscript

undamaged material

damaged material

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  Corresponding author at: Centre de Recherche de l’Armée de l’Air, École de l’air, B.A. 701, 13661 Salon-Air, France.

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