microgrid presents an efficient and novel solution for integrating many new energy generating resources with traditional distribution networks. having an appropriate protective scheme is a fundamental challenge in achieving microgrid plans. it is proven that traditional protective plans are not efficient for protecting microgrid, since the network is dynamic and the level of fault current chang...

This paper presents a new method for evaluation and simulation of inrush current in various transformers using operational matrices and Hartley transform. Unlike most of the previous works, time and frequency domain calculations are conducted simultaneously. Mathematical equations are first represented to compute the inrush current based on reiteration and then Hartley transform is used to stud...

Nonlinear dynamic model of the coupled lateral-torsional vibrations of a gear transmission system is developed, in which time-varying gear meshing stiffness, errors, and gaps are considered. The fundamental rules of the system’s multi-harmonic dynamic response have been obtained based on the time domain diagram, frequency domain diagram, phase plot, and Poincaré map. Therefore, estimation of th...

an analytical solution is presented for displacements and stresses of a three dimensional linear hyperelastic transversely isotropic layer bonded on the top of a transversely isotropic half-space subjected to an arbitrary, time-harmonic surface tangential force. the equations of equilibrium in terms of displacements are uncoupled by using a set of two potential functions introduced by eskandari...

This paper reviews the direct stiffness method for the calculation of harmonic and transient wave propagation in horizontally layered media. Developed in the early eighties by Kausel and Roësset, this method has become a standard tool for the computation of the Green’s functions in layered media. As it is based on a superposition of plane harmonic waves in the frequency-wavenumber domain, it is...

In this paper, the free vibration analysis of moderately thick rectangular plates axially moving with constant velocity and subjected to uniform in-plane loads is investigated by the spectral finite element method. Two parallel edges of the plate are assumed to be simply supported and the remaining edges have any arbitrary boundary conditions. Using Hamilton’s principle, three equations of moti...

processing map for hot working of ti-if steel has been developed in the temperature range of 750 to 1100 °cand strain rate of 0.01 to 100 s-1. this map in the austenite region exhibits a single domain with a peak efficiencyof 45% occurring at 1025 °c and strain rate of 0.02 s-1. the domain extends over the temperature range of 1000to 1100 °c and strain rate range of 0.01 to 1 s-1. the true stre...

A time domain approach is used in this paper to identify unknown dynamic forces applied on two dimensional frames using the measured dynamic structural responses for a sub-structure in the two dimensional frame. In this paper a sub-structure finite element model with short length of measurement from only three or four accelerometers is required, and an iterative least-square algorithm is used t...