Bending effect on the risk for delamination at the reinforcement/matrix interface of 3D woven fabric composite using a shell-like RVE

Abstract

This paper presents a computational homogenisation-based technique for flexural effects in textile reinforced composite planar shells. An homogenisation procedure is used for the in-plane and the out-of-plane behaviour of three-dimensional woven composite shells taking the in-plane periodicity of the material into account while relaxing any periodicity tying in the thickness direction. Several types of damage (matrix or reinforcement cracking, delamination, ...) can appear in a composite material. In this paper, material non-linear computations are used to assess the importance of bending on the risk for delamination at the reinforcement/matrix interface. The normal and tangential stresses at the interface are computed and a simplified criterion for delamination is used for this purpose. The effect of flexural loading on the stress components responsible for a potential delamination failure mode at the interface is analysed. The values of interface stresses obtained by means of flexural homogenisation are compared with 3D homogenisation results using periodicity constraints along the thickness direction, and compared qualitatively with experimental facts available from the litterature. The importance for taking flexural effects into account properly is emphasized. * Corresponding author. Tel. : +32 2 650 27 42 ; Fax : +32 2 650 27 82 On leave at

Modelling of Failure of Woven Composites. Part 2: Experimental and Numerical Justification of the Interzone Concept

“…However, this will not prevent the efficiency of the new enriched concept of interzone being demonstrated. Indeed, it will be shown that the new interzone concept allows the experimental or numerical tendancies already demonstrated in earlier papers to be retrieved [7,9,19,29]: qualitative results and conclusions obtained in a general way are a particularly useful method to demonstrate the efficiency of the interzone concept. For that, the following questions will be examined:…”

“…The approach has been to show that previous experimental or numerical analyses [7,9,19,29] of the failure of woven composites under classic loading configurations, (tensile loading, bending) can be easily retrieved by using the interzone concept (Tables 1, 2, 3,4,5).…”

“…a Versus the normal curvilinear abcissa, along the mean line. bVersus the normal z coordinate, in the cross-section of peaks and troughs -tensile loading in the (x) axial direction representing the principal warp direction; -bending above the chosen axis (y), of which the points of application are aligned with the principal weft (y)[19].…”

Computation of the effective mechanical properties including nonclassical moduli of 2.5D and 3D interlocks by micromechanical approaches

“…The development of design tools dedicated to woven composites [35] and domain decomposition techniques has been accompanied by an increasing use of FE techniques for the computation of 3D woven composites, see Ref. [36] and references therein.…”

“…Besides the tensile and shear moduli, the flexural rigidities can also be evaluated, which constitutes an original aspect; the bending behavior is equally important as shear, for instance in shape forming applications and even for the study of delamination [36]. From a numerical viewpoint, the developed algorithms can easily be implemented as they rely on a text file including all necessary input data (geometry of the structure and microscopic properties of the yarns in terms of their geometry and mechanical moduli).…”