Application of Data Communication to the Detection and Correction of Power System Faults

Data communication is an important part in modern industrial processes and is necessary in automation, monitoring, and protection purposes. This paper aims at designing a real time communication between two computers for interchanging the state of a three phase circuit to emulate a transmission line protection system in power substation. The circuit designed in Proteus ISIS is based on "symmetrical component theory" and the algorithm for exchanging data between two computers is built using TCP/IP protocol in LABVIEW environment. The application consists of monitoring and controlling three phase lines by sending the data collected to one of the computers and sending the commands back to trip relays if any fault is detected. The purpose is to prevent the propagation of this fault and to connect other sources to maintain the flow of power to the load

Harmonic response computation of viscoelastic multilayered structures using a ZPST shell element

International audienceno abstrac

Dynamic damping properties of thermoplastic elastomers based on EVA and recycled ground tire rubber

Recycling waste tires being important for both economical and environmental reasons, ground tire rubber can be blended to other polymers, modifying their properties. In order to characterize and explain these modifications, an experimental study was carried out concerning the improvement on the dynamic damping properties when adding recycled ground tire rubber (GTR) fillers to an elastomeric matrix (Ethylene Vinyl Acetate EVA). To evaluate the influence of both the ground tire rubber and the porosity in a GTR/EVA composite, three samples have been elaborated by injection: the EVA matrix alone, a GTR/EVA composite and a GTR/EVA porous composite. Dynamic measurements of the samples were performed using Dynamic Mechanical Thermal Analysis ‘DMTA’. The Young's modulus and loss factor of these materials are estimated by using the frequency-temperature equivalence introduced by Williams-Landel-Ferry (WLF) expanding the measurement of the dynamic properties over a wider range of frequencies. This method showed that in low frequency bandwidth the loss factor has been improved by the addition of GTR to the EVA matrix. The α-relaxation activation energy showed lower activation energy for both of the GTR filled composites leading to the conclusion that the mobility of the polymer chains has been improved by addition of GTR. The impact behavior study carried out using a weight drop-test experiment also concluded to better impact energy absorption for the GTR filled composites at the expense of a larger maximum strain

Behavior of crystalline silicon under huge electronic excitations: A transient thermal spike description

International audienceRecent experimental works devoted to the phenomena of mixing observed at metallic multilayers Ni/Si irradiated by swift heavy ions irradiations make it necessary to revisit the insensibility of crystalline Si under huge electronic excitations. Knowing that Ni is an insensitive material, such observed mixing would exist only if Si is a sensitive material. In order to extend the study of swift heavy ion effects to semiconductor materials, the experimental results obtained in bulk silicon have been analyzed within the framework of the inelastic thermal spike model. Provided the quenching of a boiling (or vapor) phase is taken as the criterion of amorphization, the calculations with an electron–phonon coupling constant g(300 K) = 1.8 x 1012 W/cm3/K and an electronic diffusivity De(300 K) = 80 cm2/s nicely reproduce the size of observed amorphous tracks as well as the electronic energy loss threshold value for their creation, assuming that they result from the quenching of the appearance of a boiling phase along the ion path. Using these parameters for Si in the case of a Ni/Si multilayer, the mixing observed experimentally can be well simulated by the inelastic thermal spike model extended to multilayers, assuming that this occurs in the molten phase created at the Ni interface by energy transfer from Si

Melting of Au and Al in nanometer Fe/Au and Fe/Al multilayers under swift heavy ions: A thermal spike study

Knowing that Fe is sensitive to swift heavy ion irradiations whereas Au and Al are not, the behavior of nanometric metallic multilayer systems, like [Fe(3 nm)/Au(x)](y) and [Fe(3 nm)/Al(x)](y) with x ranging between 1 and 10 mn, were studied within the inelastic thermal spike model. In addition to the usual cylindrical geometry of energy dissipation perpendicular to the ion projectile direction, the heat transport along the ion path was implemented in the electronic and atomic sub-systems. The simulations were performed using three different values of linear energy transfer corresponding to 3 MeV/u of Pb-208, Xe-132 and Kr-84 ions. For the Fe/Au system, evidence of appearance of a molten phase was found in the entire Au layer, provided the Au thickness is less than 7 nm and 3 nm for Pb and Xe ions, respectively. For the Fe/Al(x) system irradiated with Pb ions, the Al layers with a thickness less than 4 nm melt along the entire ion track. Surprisingly, the Fe layer does not melt if the Al thickness is larger than 2 nm, although the deposited energy surpasses the electronic stopping power threshold of track formation in Fe. For Kr ions melting does not occur in any of the multilayer systems

Multi-axial testing of thick adhesive bonded joints of fibre reinforced thermoplastic polymers

International audienc

Latent ion tracks were finally observed in diamond

Abstract Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2–9 MeV C60 fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which π-bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS). Since the melting transition is not induced in diamond at atmospheric pressure, conventional inelastic thermal spike calculations cannot be applied. Two-temperature molecular dynamics simulations succeeded in the reproduction of both the track formation under MeV C60 irradiations and the no-track formation under GeV monoatomic ion irradiations

Localisation analysis in masonry using Transformation Field Analysis

In the present paper, the Transformation Filed Analysis (TFA) methodology is used in the multi-scale analysis of cracking localisation in masonry. The related assumption of uniform inelastic strain field in each sub-domain allows reducing the computational cost of such computations without significantly compromising on solution accuracy. The relations underlying the TFA averaging scheme are recalled. The evaluation of the corresponding consistent tangent homogenised stiffness, required in acoustic tensor-based localisation analysis, is also derived. The average RVE mechanical response is performed for two sets of micro-mechanical material laws for mortar joints, based on both damage and damage coupled with plasticity. For these two sets of fine-scale laws, localisation analyses are performed for RVEs under stress proportional loading, showing that meaningful average localisation orientations are properly detected by the acoustic tensor-based loss of ellipticity criterion. Furthermore, the capability of the pure damage micromechanical model combined with TFA to reproduce the failure envelope of typically running bond masonry subjected to uniform biaxial loads is demonstrated through a comparison with available experimental data. Finally, the energetic aspects for the selection of localised solutions are discussed. As a result, the TFA-based averaging scheme is shown to yield meaningful homogenised localisation results, thereby allowing envisioning its use in nested multi-scale computations.info:eu-repo/semantics/publishe