Stress redistributions in unit cells of fibre-reinforced polymer composites with interface degradation

LUIS A. GODOY; VICTORIA MONDRAGON; MIGUEL A. PANDO; FELIPE J. ACOSTA

Int. J. of Microstructure and Materials Properties

Inderscience

Lugar: Geneve; Año: 2013 vol. 8 p. 185 - 206

1741-8410

Experimental evidence indicates that the main damage mechanisms found in fibre-reinforced composites under static loading or environmental action are matrix damage, fibre damage, and interface damage (including debonding), leading to various forms of strong inhomogeneities at the micromechanical level. Such inhomogeneities have been computationally modelled by means of degradation of the constituent properties and/or as a finite set of defects in the composite constituents or at their interface. To carry out the micromechanical analysis of materials with periodic structure, a unit cell is usually modelled in order to represent the local behaviour of the material, including a single or several fibres, depending on the symmetry of the considered configuration. The main objective of this paper is to identify the stress redistributions that take place at the unit cell level, in which damage has already occurred due to an independent process. Such situation is typical of aging, in which severe degradation may have taken place due to environmental action before loads are applied to the structural component. A deterministic approach is carried out to illustrate the main features of the transverse behaviour of a unidirectional fibre?reinforced composite under static loading. Damage is modelled by means of interface defects, in which the number and size of defects are considered as parameters of the damaged configuration and also by changes in material properties. The two-dimensional problem is solved using a general purpose finite element code. The results show the extent of damage propagation to be expected in several configurations with inhomogeneities.