Issue 41

M.F. Funari et alii, Frattura ed Integrità Strutturale, 41 (2017) 524-535; DOI: 10.3221/IGF-ESIS.41.63 530 Figure 3 : Schematic representation of the algorithm for layered structure, crack initiation and evolution. Layered Structure – Multiple debonding mechanisms The loading scheme, reported in Fig. 4, is based on clamped end conditions and concentrated untisymmetric opening forces. The mechanical properties assumed for the laminate are reported in Tab. 1, whereas those concerning the cohesive interface are reported in Tab. 2. The numerical model is discretized along the thickness by using one mathematical layer for each sublaminate, whereas, for the interfaces, three ALE elements are introduced between the sublayers, in which the crack initiation could be potentially activated. The analysis is developed under a displacement control mode, to ensure a stable crack propagation. In order to verify the stability and accuracy of the solution, several mesh discretizations, ranging from a coarse uniform distribution to a refined one, are considered. In particular, for the proposed model, the following numerical cases are analyzed:  uniform discretization with a characteristic element mesh equal ΔD/L=2/200 (M1) with 1841 DOFs;  uniform discretization with a characteristic element mesh equal ΔD/L=1/200 (M2) with 3633 DOFs; In addition, in order to verify the consistency of the proposed approach, a model based on Pure Cohesive approach, namely PC1, is developed, in which a uniform discretization of the mesh with a length equal ΔD/L=0.2/200 involving in 12012 DOFs is adopted. Figure 4 : Laminate configuration and loading scheme. 1 E [GPa] 12 G [GPa] c L [mm] c B [mm] h [mm] H [mm] e [mm]  [kg/mc] 130 3 200 20 2 12 20 1500 Table 1 : Geometrical and mechanical properties of the laminate.