The demand for more efficient and functional materials has been driving major developments in the design of composite materials. As a result, fibre composites are increasingly becoming complicated and often tailored to meet the needs of different industries. There are numerous techniques to reinforce composite materials, including 3D braiding, tufting and embroidery – all of which share a common feature: there is not a representative block at yarn level. Thus, these materials are not considered homogeneous with the traditional sense of meaning. This makes it more difficult to determine the stresses and strains when composites are subjected to forces. In the EU-funded project INTERCOM (New inter-scale techniques for damage analysis of novel composite architectures), scientists simplified modelling of damage accumulation and failure in composites by developing an entirely new multi-scale framework that takes into account all the heterogeneities and constituents of the material. The proposed methodology applied in composites lacking a characteristic representative element is based on separating space and scales. The team demonstrated that a complex interaction between unit cells in non-periodic textile laminates can be successfully replicated by the analysis of a single unit cell. A library of new numerical tools was developed that helped build geometrical models of patterned fibre composites featuring different thickness, shape distortion and ply curvature. Experiments conducted on composites manufactured with different methods validated the new models against surface strains, damage onset, stiffness degradation, damage modes and crack patterns. INTERCOM's methodology makes it simpler to describe and predict failure of composite structures. In the future it will be further improved and applied to enhance composite performance not only at structural but also at component level.
Structural changes, composite materials, damage analysis, multi-scale framework