Issue 52

R. Hadj Boulenouar et alii, Frattura ed Integrità Strutturale, 52 (2020) 128-136; DOI: 10.3221/IGF-ESIS.52.11 129 [16-18]. The Polymeric nanocomposites are usually defined as a combination of a polymer matrix and nanometric particles [19]. The possibilities of improving the mechanical or thermal properties and the development of new materials by nanoparticles have found applications in academia and industry. Several experimental and theoretical studies have been carried out on the mechanical properties of microphones and nanocomposites. Many papers report improved polymer properties more efficiently using nanoparticles than with microparticles [20]. The epoxy resin is a rigid polymer with good chemical stability, mechanical and electrical properties. It is widely used as a matrix of composite materials reinforced by fillers and as adhesives [21, 22]. When cured, the epoxy is amorphous and highly cross-linked (i.e. thermosetting polymers). This microstructure provides many useful properties for engineering applications, such as a modulus of elasticity, high and failure resistance, low creep, and good performance at high temperatures [23]. However, the structure of the epoxy also leads to very undesirable properties when it is a relatively fragile material, with a low resistance to initiation and growth of the cracks. The thermal loading effect on free vibration characteristics of carbon nanotubes (CNTs) with multiple cracks has been studied [24]. The nanoparticles have been widely used in epoxy matrix composites as reinforcements. Compared to micro-loaded composites with nanoparticles open up a wide range of potential new applications, due to their improved engineering properties, such as stiffness and hardness, and other beneficial functions such as the barrier against nanoparticles, humidity and flame retardancy [25]. The objective of this work is to analyze by three-dimensional finite element method using the Abaqus calculation code, the stress distribution of shear and peeling in the adhesive joint used to assembly two aluminum plates. Several parameters have been highlighted such as the stiffness of the nanostructured adhesive and their size, in order to see the effect of the silica nanoparticles' dispersion imbedded in the epoxy resin on the charge transferred in the adhesive layer. G EOMETRIC MODEL AND MECHANICAL PROPERTIES he adhesively bonded single-lap joint studied in the present work is shown in Fig. 1. The two adherends used were aluminum alloy plates (2024-T3) of dimensions 200 mm long, 20 mm wide, 2 mm thickness. The mechanical properties of the adherends were as follows: Poisson's ratio ν = 0.33, Young's modulus E = 69 GPa. The mechanical properties of the adhesives investigated were: Poisson's ratio ν ad = 0.33, Young's modulus E = 3.5 GPa [26]. Figure 1: Geometrical model. B OUNDARY C ONDITIONS chematic of the entire model (Fig. 2), including the fixed connection (zero displacement) at the left end, a distributed load of 40 MPa was applied at the right end of the upper substrate in the x-direction. The joint is oriented along the x, z is the direction of the width and y is the direction normal to the joint plane. Figure 2: Boundary conditions for the symmetry FE model. T S Upper adherend Lower adherend 0.2