Effect of thermal residual stresses on matrix failure under transverse tension at micromechanical level: A numerical and experimental analysis

International audienceIn the present work the influence at micromechanical scale of thermal residual stresses, originated in the cooling down associated to the curing process of fibrous composites, on inter-fibre failure under transverse tension is studied. In particular, the effect of the presence of thermal residual stresses on the appearance of the first debonds is discussed analytically, whereas later steps of the mechanism of damage, i.e. the growth of interface cracks and their kinking towards the matrix, are analysed by means of a single fibre model and making use of the Boundary Element Method. The results are evaluated applying Interfacial Fracture Mechanics concepts. The conclusions obtained predict, at least in the case of dilute fibre packing, a protective effect of thermal residual stresses against failure initiation, the morphology of the damage not being significantly affected in comparison with the case in which these stresses are not considered. Experimental tests are carried out, the results agreeing with the conclusions of the numerical analysis

Fundamental solutions for steady-state heat transfer in an exponentially graded anisotropic material

Abstract. Heat conduction in an anisotropic inhomogeneous medium is considered. The conductivities vary exponentially in one fixed but arbitrary direction. The Green's function corresponding to a point source is constructed. Two methods are used, one using Fourier transforms and one involving certain changes of variables in the governing partial differential equation. Solutions in both two and three dimensions are derived. They can be used as a basic ingredient in the formulation of boundary integral equations for graded anisotropic materials. Mathematics Subject Classification (2000) . 35A08, 80M15

Quasistatic delamination of sandwich-like Kirchhoff-Love plates

A quasistatic rate-independent adhesive delamination problem of laminated plates with a finite thickness is considered. By letting the thickness of the plates go to zero, a rate-independent delamination model for a laminated Kirchhoff-Love plate is obtained as limit of these quasistatic processes. The same dimension reduction procedure is eventually applied to processes which are sensitive to delamination modes, namely opening vs. shearing is distinguishe