Payam Soltani

Bio: Payam Soltani is an academic researcher from Birmingham City University. The author has contributed to research in topics: Nonlinear system & Vibration. The author has an hindex of 11, co-authored 41 publications receiving 420 citations. Previous affiliations of Payam Soltani include Ferdowsi University of Mashhad & Coventry University.

Vibration and instability of a viscous-fluid-conveying single-walled carbon nanotube embedded in a visco-elastic medium

Abstract: In this study, for the first time, the transverse vibrational model of a viscous-fluid-conveying single-walled carbon nanotube (SWCNT) embedded in biological soft tissue is developed. Nonlocal Euler–Bernoulli beam theory has been used to investigate fluid-induced vibration of the SWCNT while visco-elastic behaviour of the surrounding tissue is simulated by the Kelvin–Voigt model. The results indicate that the resonant frequencies and the critical flow velocity at which structural instability of nanotubes emerges are significantly dependent on the properties of the medium around the nanotube, the boundary conditions, the viscosity of the fluid and the nonlocal parameter. Detailed results are demonstrated for the dependence of damping and elastic properties of the medium on the resonant frequencies and the critical flow velocity. Three standard boundary conditions, namely clamped–clamped, clamped–pinned and pinned–pinned, are applied to study the effect of the supported end conditions. Furthermore, it is found that the visco-elastic foundation causes an obvious reduction in the critical velocity in comparison with the elastic foundation, in particular for a compliant medium, pinned–pinned boundary condition, high viscosity of the fluid and small values of the nonlocal coefficient.

Piezoelectric vibration damping using resonant shunt circuits: an exact solution

Abstract: The objective of this paper is to propose an exact closed-form solution to the optimization of piezoelectric materials shunted with inductive-resistive passive electrical circuits. Realizing that Den Hartogʼs method which imposes fixed points of equal height in the receptance transfer function is approximate, the parameters of the piezoelectric tuned vibration absorber are calculated through the direct minimization of the maxima of the receptance. The method is applied to a one-degree-of-freedom primary oscillator considering various values of the electromechanical coupling coefficients.

Studying the Tensile Behaviour of GLARE Laminates: A Finite Element Modelling Approach

Abstract: Numerical simulations based on finite element modelling are increasingly being developed to accurately evaluate the tensile properties of GLARE (GLAss fibre REinforced aluminium laminates). In this study, nonlinear tensile behaviour of GLARE Fibre Metal Laminates (FML) under in-plane loading conditions has been investigated. An appropriate finite element modelling approach has been developed to predict the stress–strain response and deformation behaviour of GLARE laminates using the ANSYS finite element package. The finite element model supports orthotropic material properties for glass/epoxy layer(s) and isotropic properties with the elastic–plastic behaviour for the aluminium layers. The adhesion between adjacent layers has been also properly simulated using cohesive zone modelling. An acceptable agreement was observed between the model predictions and experimental results available in the literature. The proposed model can be used to analyse GLARE laminates in structural applications such as mechanically fastened joints under different mechanical loading conditions.

The nonlinear piezoelectric tuned vibration absorber

Abstract: This paper proposes a piezoelectric vibration absorber, termed the nonlinear piezoelectric tuned vibration absorber (NPTVA), for the mitigation of nonlinear resonances of mechanical systems. The new feature of the NPTVA is that its nonlinear restoring force is designed according to a principle of similarity, i.e., the NPTVA should be an electrical analog of the nonlinear host system. Analytical formulas for the NPTVA parameters are derived using the homotopy perturbation method. Doing so, a nonlinear generalization of Den Hartog's equal-peak tuning rule is developed for piezoelectric vibration absorbers.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …