Effective elastic properties of layered composites considering non-uniform imperfect adhesion

In this study, the effective elastic properties of layered composites are predicted by considering the influence of non-uniform imperfect adhesion. In practical terms, the influence of non-uniform imperfection on the effective properties of layers is evaluated when debonding or delamination occurs between adjacent layers. Thus, the effective properties of two- and three-layer composites with imperfect and perfect interfaces are calculated using the finite element method and an analytical technique based on the two-scale asymptotic homogenization method, respectively. In the analyses, it was used a two-layer model with imperfect interface conditions and a three-layer model with perfect conditions to derive analytical expressions of the interlayer properties, which are equivalent to the effect of the imperfection (e.g., debonding). Our numerical results demonstrate that the three-layer model provides an excellent approximation of the two-layer one and it illustrates how the effective properties of the layered composites made from titanium Ti6Al4V and ceramic AD-96 are affected by non-uniform imperfect adhesion.