In the current literature, the nanostructures are usually analysed according to nonlocal elasticity theories, that is, considering infinitesimal displacements and assuming nanostructure cross- section to be rigid and constant along the axis. An important aspect, not yet studied in-depth, concerns the study of nanostructures in finite displacements conditions, where the deformations of their cross-sections are taken into account. In such a scenario, the present research project proposes a novel dynamic formulation for geometrically exact nanobeams, by considering the deformations of the nanobeam cross-section both in the plane and out of plane (warping). Focusing attention on the mechanical behaviour of nanocomposites with both elastic cylindrical inhomogeneities and overlapping spherical inclusions, the elastic properties of such nanocomposites are analytically examined by means of the compliance contribution tensor approach for the first time. As far as nanocomposites made by nanoplates are concerned, the novelty of the present project is to apply semi-analytical approaches based on innovative theories (that is, modified-couple stress, strain gradient and micropolar theories) to study their mechanical behaviour, also examining the influence of both nonlocal parameters and applied multifield loading. Since the presence of cracks (which are common relevant defects) cannot be ignored in fabrication, the nanostructure fracture behaviour under both static and dynamic loading is also examined, by considering Euler–Bernoulli and Timoshenko cracked nanobeams (with and without elastic foundation) for such a case. In particular, the governing equations are developed by means of the stress-driven nonlocal integral model, not used before to analyse the aforementioned problem. The effects of crack severity, crack location, and local parameters on the fundamental frequencies of cracked nanobeams are investigated, by also taking into account the influence of temperature gradient. Multiple cracks are, then, intentionality formed to achieve the desired frequencies of nanostructures. Regarding the fracture mechanisms in nanocomposites, a novel analytical model, based on the ReaxFF reactive force field method, is developed in order to predict the interface crack propagation. The tasks to be undertaken for WP1 are the following.
T1.1.3 Static and dynamic formulations for geometrically exact nanobeams are proposed by considering both in plane and out of plane cross-section deformation; T1.1.4 Closed-form solution of deflections and effective elastic moduli are found for nanobeams via SDM together with surface energy concept; T1.1.5 3D large deflections of Functionally Graded (FG) porous nanobeams under various loading scenarios are analysed;
T1.2.1 Interface crack propagation in cementitious nanocomposites is analysed by employing the reactive force field method (ReaxFF); T1.2.2 A hierarchical approach for polymer nanocomposites interface modelling is proposed by describing interactions among atoms at interface;
T1.3.1 Local/nonlocal strain and stress gradient formulations in finite deformations are used to derive governing differential equations of nanobeams under both static and dynamic loading; T1.3.2 Strain-driven (NstrainG) and stress-driven (NstressG) gradient formulations are employed together with surface energy concept; T1.3.3 3D large deflections of FG porous nanobeams under various loading scenarios are analysed.