Effect of fibre arrangement on the multiaxial fatigue of fibrous composites: a micromechanical computational model

Frattura ed Integrità Strutturale. 2015;9(34):59-68 DOI 10.3221/IGF-ESIS.34.05

 

Journal Homepage

Journal Title: Frattura ed Integrità Strutturale

ISSN: 1971-8993 (Online)

Publisher: Gruppo Italiano Frattura

Society/Institution: Gruppo Italiano Frattura

LCC Subject Category: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials | Technology: Mechanical engineering and machinery | Technology: Engineering (General). Civil engineering (General): Structural engineering (General)

Country of publisher: Italy

Language of fulltext: English

Full-text formats available: PDF, Browsable

 

AUTHORS

Roberto Brighenti (University of Parma, Italy)
Andrea Carpinteri (University of Parma, Italy)
Daniela Scorza (University of Parma, Italy)

EDITORIAL INFORMATION

Peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 6 weeks

 

Abstract | Full Text

Structural components made of fibre-reinforced materials are frequently used in engineering applications. Fibre-reinforced composites are multiphase materials, and complex mechanical phenomena take place at limit conditions but also during normal service situations, especially under fatigue loading, causing a progressive deterioration and damage. Under repeated loading, the degradation mainly occurs in the matrix material and at the fibre-matrix interface, and such a degradation has to be quantified for design structural assessment purposes. To this end, damage mechanics and fracture mechanics theories can be suitably applied to examine such a problem. Damage concepts can be applied to the matrix mechanical characteristics and, by adopting a 3-D mixed mode fracture description of the fibre-matrix detachment, fatigue fracture mechanics concepts can be used to determine the progressive fibre debonding responsible for the loss of load bearing capacity of the reinforcing phase. In the present paper, a micromechanical model is used to evaluate the unixial or multiaxial fatigue behaviour of structures with equi-oriented or randomly distributed fibres. The spatial fibre arrangement is taken into account through a statistical description of their orientation angles for which a Gaussian-like distribution is assumed, whereas the mechanical effect of the fibres on the composite is accounted for by a homogenization approach aimed at obtaining the macroscopic elastic constants of the material. The composite material behaves as an isotropic one for randomly distributed fibres, while it is transversally isotropic for unidirectional fibres. The fibre arrangement in the structural component influences the fatigue life with respect to the biaxiality ratio for multiaxial constant amplitude fatigue loading. One representative parametric example is discussed.