Temat: multi-scale model - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: The key problems of local approach to cleavage fracture
Kluczowe zagadnienia w lokalnym ujęciu kruchego pękania
Autorzy:: Kotrechko, S.
Powiązania:: https://bibliotekanauki.pl/articles/279830.pdf
Data publikacji:: 2013
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: local approach to fracture
multi-scale model
local fracture stress
Opis:: Based on the suggested multi-scale model of Local Approach (LA) to fracture, four main problems of LA are considered, namely: (i) the effect of micro-stress fluctuations on the crack nuclei instability; (ii) intensity of micro-crack nucleation and its influence on fracture probability; (iii) theoretical and experimental assessment of the value of threshold stress; (iv) stochastic analysis of “multi-barrier” effect at micro-crack growth in polycrystalline metal.
W oparciu o zaproponowany wieloskalowy model lokalnego sformułowania procesu pękania (Local Approach – LA) wyróżniono cztery podstawowe problemy do rozważenia: (i) efekt fluktuacji makronaprężeń na niestabilność jądra pęknięcia, (ii) intensywność zawiązywania się mikropęknięcia i jego wpływ na prawdopodobieństwo powstania przełomu, (iii) teoretyczne i eksperymentalne oszacowanie wartości naprężenia krytycznego, (iv) stochastyczna analiza efektu „wieloprogowego” na wzrost mikropęknięcia w metalu polikrystalicznym.
Źródło:: Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 75-89
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Investigation of crack resistance in epoxy/boron nitride nanotube nanocomposites based on multi-scale methodInvestigation of crack resistance in epoxy/boron nitride nanotube nanocomposites based on multi-scale method
Autorzy:: Hemmatian, Hossein
Zamani, Mohammad Reza
Jam, Jafar Eskandari
Powiązania:: https://bibliotekanauki.pl/articles/280181.pdf
Data publikacji:: 2019
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: boron nitride nanotube
epoxy
fracture modes
finite element model
multi-scale method
Opis:: Boron nitride nanotubes (BNNTs) possess superior mechanical, thermal and electrical properties and are also suitable for biocomposites. These properties make them a favorable reinforcement for nanocomposites. Since experimental studies on nanocomposites are timeconsuming, costly, and require accurate implementation, finite element analysis is used for nanocomposite modeling. In this work, a representative volume element (RVE) of epoxy/BNNT nanocomposites based on multi-scale modeling is considered. The bonds of BNNT are modeled by 3D beam elements. Also non-linear spring elements are employed to simulate the van der Waals bonds between the nanotube and matrix based on the Lennard- -Jones potential. Young’s and shear modulus of BNNTs are in ranges of 1.039-1.041 TPa and 0.44-0.52 TPa, respectively. Three fracture modes (opening, shearing, and tearing) have been simulated and stress intensity factors have been determined for a pure matrix and nanocomposite by J integral. Numerical results indicate that by incorporation of BNNT in the epoxy matrix, stress intensity factors of three modes decrease. Also, by increasing the chirality of BNNT, crack resistance of shearing and tearing modes are enhanced, and stress intensity factor of opening mode reduced. BNNTs bridge the crack surface and prevent crack propagation.
Źródło:: Journal of Theoretical and Applied Mechanics; 2019, 57, 1; 207-219
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Rapid NEGF-based calculation of ballistic current in ultra-short DG MOSFETs for circuit simulation
Autorzy:: Hosenfeld, F.
Horst, F..
Graef, M.
Farokhnejad, A.
Kloes, A.
Iniguez, B.
Lime, F.
Powiązania:: https://bibliotekanauki.pl/articles/397995.pdf
Data publikacji:: 2016
Wydawca:: Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:: ultra-short Double-Gate MOSFET
nonequilibrium Green's function
NEGF
ballistic transport
source-to-drain tunneling
ultra-thin body
UTB
compact model
multi-scale simulation
nierównowagowe funkcje Greena
transport balistyczny
tunelowanie źródło-dren
model kompaktowy
symulacja wieloskalowa
Opis:: Shrinking gate length in conventional MOSFETs leads to increasing short channel effects like source-to-drain (SD) tunneling. Compact modeling designers are challenged to model these quantum mechanical effects. The complexity lies in the set-up between time efficiency, physical model relation and analytical equations. Multi-scale simulation bridges the gap between compact models, its fast and efficient calculation of the device terminal voltages, and numerical device models which consider the effects of nanoscale devices. These numerical models iterate between Poisson- and Schroedinger equation which significantly slows down the simulation performance. The physicsbased consideration of quantum effects like the SD tunneling makes the non-equilibrium Green’s function (NEGF) to a stateof-the-art method for the simulation of devices in the sub 10 nm region. This work introduces a semi-analytical NEGF model for ultra-short DG MOSFETs. Applying the closed-form potential solution of a classical compact model, the model turns the NEGF from an iterative numerical solution into a straightforward calculation. The applied mathematical approximations speed up the calculation time of the 1D NEGF. The model results for the ballistic channel current in DG-MOSFETs are compared with numerical NanoMOS TCAD [1] simulation data. Shown is the accurate potential calculation as well as the good agreement of the current characteristic for temperatures down to 75 K for channel lengths from 6 nm to 20 nm and channel thickness from 1.5 nm to 3 nm.
Źródło:: International Journal of Microelectronics and Computer Science; 2016, 7, 2; 65-72
2080-8755
2353-9607
Pojawia się w:: International Journal of Microelectronics and Computer Science
Dostawca treści:: Biblioteka Nauki

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