Effect of fibre arrangement on the multiaxial fatigue of fibrous composites: a micromechanical computational model
Journal Title: Frattura ed Integrità Strutturale - Year 2015, Vol 9, Issue 34
Abstract
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.
Authors and Affiliations
Roberto Brighenti, Andrea Carpinteri, Daniela Scorza
Keywords
Related Articles
- EP ID EP127965
- DOI 10.3221/IGF-ESIS.34.05
- Views 70
- Downloads 0
Ultrasonic fatigue testing device under biaxial bending
A new fatigue testing device has been developed to test specimens under biaxial loading at 20 kHz. A flat smooth specimen with a disc geometry is placed on a torus frame and cyclically loaded at the center of its&...
Multi-purpose fatigue sensor. Part 2. Physical backgrounds for damages accumulation and parameters of their assessment
The characteristic informative parameters for defect detection to be used in fatigue sensors have been established. Their development is interpreted in terms of scale levels of deformation and fracture. Damage acc...
Fretting fatigue crack propagation rate under variable loading conditions
Fretting fatigue experiments aim to represent industrial problems and most of them endure variable loading. Being able to assess lifetime of assemblies, especially for low propagation rate conditions, is essential...
Mechanical characterization of basalt woven fabric composites: numerical and experimental investigation
Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabri...
Effetto delle dimensioni del cordone di saldatura sulla resistenza a fatica dei giunti a croce
La scelta della dimensione da assegnare al cordone di saldatura nel caso di giunzioni saldate a croce può presentarsi problematica, specie quando gli spessori delle lamiere che formano il giunto sono differenti tra loro....