The yarns and the out-of-yarn matrix in the composites are modeled by an extended Hashin criterion and an extended Drucker-Prager criterion, respectively.
Table 4 Nomenclature of damage types in off-axis tension test based on (Saleh et al. 2016c) Code Damage type F Free edge matrix crack between yarns Z Z-binder induced damage T Transverse crack within yarns D Inter-yarn matrix delamination S Slippage between in-plane tows "warp/weft".
A novel meshing methodology incorporates branching cohesive yarn-to-yarn and yarn-to matrix interfaces for modelling delamination.
Doitrand and Fagiano (2015) applied an advanced failure criterion including different damage mechanisms such as fibre failure, transverse and out-of-plane cracking for the yarns, and inter-yarn-matrix cracking to study mechanical behaviour of a four-layer plain-weave glass fibre/epoxy matrix composite at the mesoscopic scale.
Traditional ply-based failure criteria, such as Tsai-Wu and Tsai-Hill, consider a yarn-matrix system as a whole and, therefore, they are not suitable to predict whether the failure occurs inside a yarn, a matrix, or at their interfaces (Tolosana et al. 2012).
Still, introducing cracks inside complex yarns-matrix architecture and re-meshing are computationally intensive.
Then, beam and plate stiffness matrices are predicted based on the yarn and matrix properties using MSG.
The shear failure at the interface between yarn and matrix is considered as the creation of a tunnel crack at the interface between yarn and matrix.
Fig. 21 Yarn and matrix interface debonding of composite in 10th cycle (Wu et al. 2014b).
Three special element types, called yarn element, matrix element and mixed element, are derived.
The spline approximation provides continuity of displacement and stress components within each yarn and matrix subregion.
