Journal of Multiscale Modelling

The propagation characteristics of anti-plane waves, i.e., the quasi-shear horizontal (QSH) waves and the carrier (CA) waves through a piezoelectric semiconductor (Piezo-SEMI) infinite space are discussed in this paper. First, the elastic, piezoelectric, dielectric, carrier mobility and diffusion constants in the considered propagation coordinate system are obtained by Bonde transformation from those in the crystal axis coordinate system. For anti-plane case, the secular equation with the mechanical, electric and the carrier concentration fields of the anti-plane waves through a Piezo-SEMI infinite space is derived. We obtain all possible wave modes, i.e., QSH waves and CA waves, that propagate in the Piezo-SEMI material by solving the secular equation. Then, the wave speeds and attenuation of QSH waves and CA waves are obtained. The steady-state carrier concentration and biasing electric field have significant effects on dispersion and attenuation of the QSH waves and the CA waves, and the sensitive areas to the wave velocity and attenuation are obtained.

This paper is part of an activity related to a specific hybridization process for an existing and commercialized motorcycle engine. The electric motor is mechanically connected to the engine using the original valvetrain transmission chain leading to a P0 hybrid architecture. The aim of this work is to analyze the structural behavior of the chain now used as torque transmission device. Although, on one side, the maximum torque of the electric motor induces a stress state on the chain lower than its fatigue limit, on the other side, the dynamic behavior of the system strongly influences the maximum stress on the chain. In fact, the main source of load on the chain is derived from the torsional oscillation of the system. Engines’ rotational speed irregularity can be easily estimated through common analytical approaches which consider the contribution of combustion and inertial forces on the instantaneous torque produced by the crank mechanism and the overall inertia of the moving parts. In addition, more detailed lumped-parameters and Multibody dynamic models are here developed in order to estimate the actual instantaneous engine speed taking into account the onset of possible high-order vibration phenomena. Specifically, the influence of the torsional vibration behavior of the internal combustion engine is investigated on the resulting stress on the chain. Finally, the structural chain integrity is assessed by performing a fatigue analysis considering the actual operating conditions.

This work presents a computational study on the impact of carbon nanotube (CNT) enriched matrix on the performance of 1–3 lead-free piezoelectric periodic composites. Specifically, we investigate a piezoelectric composite system consisting of $x_3$ parallel aligned fibers of polycrystalline barium titanate (BaTiO₃) embedded in a polydimethylsiloxane (PDMS) matrix doped with multiwalled CNT. The effective properties and several figures of merit have been obtained to evaluate the performance of this composite system as is typically done for these materials used for sensing, actuating, or harvesting applications. The results reveal that, in lead-free BaTiO₃/PDMS piezocomposites, the addition of CNTs in the PDMS matrix should be $f_{\mathrm{\text{CNT}}}\approx 0.5f_c$ “being $f_c$ the percolation threshold”, but not higher. In another case, we will only improve the performance of the lead-free piezocomposite for sensing or actuating, but not for energy harvesting applications. This study provides insights into the use of multiwalled CNTs in lead-free piezocomposites and suggests the optimal concentration of CNTs to enhance their performance. The findings have potential implications for the development of new piezoelectric materials and devices for sensing and harvesting applications.

In this paper, the plane wave propagation, in a homogeneous, isotropic thermoelastic solid in the presence of Thomson effect is studied. The problem is solved in the context of the dual-phase-lag model and Lord and Shulman theory. The heat conduction equation is influenced by the Thomson coefficient. The analytical solution of the problem is acquired by using the normal mode method to obtain the stress components, the temperature and the displacement components. The variations of the field quantities have been depicted graphically in the dual-phase-lag model and Lord and Shulman theory for an insulated boundary. From numerical calculations, the effect of Thomson parameter on a homogeneous, isotropic, electro-magneto-thermoelastic material is revealed and discussed.