In this paper, the mechanical properties of plasma-sprayed coatings are evaluated using the technology of nanoindentation. According to the indentation curve (load versus indenter’s displacement), which is recorded in an indentation experiment, the mechanical behaviour of the plasma-sprayed coating is investigated via inverse analysis using numerical optimization algorithms. The tip rounding of imperfect indenter is investigated in parameter identification. Subsequently, the hardness on the top surface and on the vertical cross section of the plasma-sprayed coating are investigated. The results show that the hardness on the top surface of the coating depends on the indentation depth. Moreover, the results show that the hardness on the cross section of the coating is significantly affected by the substrate if the indentation impression is too close to the coating-substrate interface.

In the present study, an enriched continuum mechanics framework is employed to study the surface effects on bending behavior of silver nanowires (NWs) resting on elastic substrate. The Timoshenko beam theory and the Laplace-Young equation are employed to investigate static behavior of silver NWs lying on Winkler-Pasternak elastic substrate. Three types of boundary conditions are considered as doubly simply supported (S-S), doubly clamped (C-C) and cantilevered (C-F). Analytical solutions are obtained for NWs with surface crystallographic orientation of [001] subjected to a concentrated external force. By defining different normalized contact stiffness, extensive numerical results are carried out to study the influence of effective parameters such as substrate, surface, aspect ratio (L/D) and diameter on the stiffness of NWs. According to the obtained results, the effect of surface and its rate of variation on stiffness of NWs lying on Winkler and Winkler-Pasternak elastic foundation models are more significant in (C-F) type of boundary condition compared to the NWs without foundation. By increasing the modulus of elastic substrate, the effect of shear deformation increases which it is more considerable in (C-C) and (S-S) NWs resting on the Winkler-Pasternak and Winkler substrate models, respectively.

This paper presents experimental and numerical studies of drop tests of corrugated cardboard packaging containing different foam cushions. An efficient homogenization model for the corrugated cardboard has been developed. In our homogenized model, the corrugated cardboard is represented by a 2D plate. Instead of using a local constitutive law (relating the strains to the stresses) at each material point, the homogenization gives the global rigidities (relating the generalized strains to the resultant forces) for the equivalent homogeneous plate. This model was implemented into the FE software ABAQUS. The foam behaviour was experimentally determined and modelled using a crushable foam model of ABAQUS. The packages are tested in free fall from a given height on a rigid floor. The deceleration of the packed product was recorded using a triaxial accelerometer. The numerical results obtained using the FE simulation with the homogenized model agree well with the experimental results. We have also shown that the contribution of the corrugated cardboard box to the shock response could not be neglected in the design of cushioning package.

The study of nonlinear dynamic behavior of laminate composed of steel and rubber layers also referred as “Shim”, used for vibro-acoustic insulation in brake system, is investigated. The simulation of the vibro-acoustic nonlinear behavior of Shim depending on frequency, taking into account the large deformations and various nonlinear hyper-viscoelastic laws of rubber are considered. This paper presents a solution to contribute in the identification of the best design of Shim in terms of damping vibration of brake systems, using analytical and numerical method. The choice of the best structure depends essentially on the nature of rubber, on the stacking sequence of materials, on their thickness, on the number of layers and on volume fraction of rubber. An analytical study, with the use of the transfer matrix method is presented. A model on the finite element software ANSYS is constructed. The results lead to conclusions about the best structure and design of Shim in term of vibro-acoustic insulation.

In this paper, the cyclostationary characteristics of electrical signals will be exploited in order to detect the rotor faults of an asynchronous machine. These defects are the most complex in terms of detection since they interact with the 50 Hz carrier with a weak band occupied in frequency. The testing ground used includes an industrial three-phase wound rotor asynchronous motor of 400 V, 6.2 A, 50 Hz, 3 kW, 1385 rpm characteristics. The rotor fault has been carried out by adding an extra 40 mΩ resistance on one of the rotor phases (i.e. 10% of the rotor resistance value per phase, Rr = 0.4Ω). From the stator voltage and current acquisition, and by application of the Time Synchronous Averaging (TSA) method to the stator current, the electrical signal will be conditioned in order to obtain a sensitive indicator allowing to easily distinguish the healthy cases from defective ones.

Dimensional errors of the parts from a part family cause the initial misplacement of the workpiece on the fixture affecting the final product quality. Even if the part is positioned correctly, the external machining forces and clamping load cause the part to deviate from its position. This deviation depends on the external load and the fixture stiffness. In this article, a comprehensive analytical model of a 3-2-1 fixturing system is proposed, consisting of a kinematic and a mechanical part. The kinematic model relocates the initially misplaced workpiece in the machine reference through the axial advancements of six locators taking all the fixturing elements to be rigid. The repositioned part then shifts again from the corrected position due to the deformation of fixturing elements under clamping and machining forces. The mechanical model calculates this displacement of the part considering the locators and clamps to be elastic. The rigid cuboid baseplate, used to precisely relocate the workpiece, is also considered elastic at the interface with the locators. Using small displacement hypothesis with zero friction at the contact points, Lagrangian formulation enables us to calculate the rigid body displacement of the workpiece, deformation of each locator, as well as the stiffness matrix and mechanical behavior of the fixturing system. This displacement of the workpiece is then finally compensated by the advancement of the six axial locators calculated through the kinematic model.

Probability Density Function (PDF) is often selected to couple chemistry with turbulence for complex reactive flows since complex reactions can be treated without modeling assumptions. This paper describes an investigation into the use of the particles approximation of this transport equation approach applied to Homogeneous Charge Compression Ignition (HCCI) combustion. The model used here is an IEM (Interaction by Exchange with the Mean) model to describe the micromixing. Therefore, the fluid within the combustion chamber is represented by a number of computational particles. Each particle evolves function of the rate of change due to the chemical reaction term and the mixing term. The chemical reaction term is calculated using a reduced mechanism of n-heptane oxidation with 25 species and 25 reactions developed previously. The parametric study with a variation of the number of particles from 50 up to 104 has been investigated for three initial distributions. The numerical experiments have shown that the hat distribution is not appropriate and the normal and lognormal distributions give the same trends. As expected when the number of particles increases for homogenous mixture (i.e. high turbulence intensity), the in-cylinder pressure evolution tends towards the homogeneous curve. For both homogeneous and inhomogeneous (i.e. low turbulence intensity) cases, we have found that 200 particles are sufficient to model correctly the system, with a CPU time of a few minutes when a restriction of initial distribution is adopted.