A Self-Consistent Scheme for the Relaxation Behavior of Metals

1981 ◽  
Vol 48 (4) ◽  
pp. 779-784 ◽  
Author(s):  
G. J. Weng

We identify in this paper that stress relaxation in metals is a “strain-free” process. The corresponding self-consistent relations between the strain, and stress variations of a grain and of its aggregate are derived from Eshelby’s solution of an ellipsoidal inclusion. It is shown that, under such a process, the strain in a more favorably oriented grain continues to rise and that its stress decreases more drastically than that of the aggregate; conversely, for a less favorably oriented grain, its strain decreases and its stress relaxes less. The self-consistent relations are supplemented with a temperature-dependent, physically consistent constitutive equation for the slip system. Such an equation enables us to determine the single crystal constants at one temperature from the polycrystal data at another temperature; it also makes the self-consistent scheme applicable to the varying-temperature environment. The established theory was finally applied to predict the relaxation behavior of an RR-59 aluminum alloy under combined stress; the results showed reasonably good agreement with the experimental data.

Author(s):  
Joseph T. Klamo ◽  
Ray-Qing Lin

The accurate prediction of the track of a ship maneuvering in a seaway is one of the most important tasks in seakeeping. Most ship maneuvering studies, both experimental and numerical, focus on maneuvering in calm water. Recently, Lin and Klamo (2010) used the Digital Self-consistent Ship Experimental Laboratory (DiSSEL) to study the ship track of a turning circle maneuver in a wave field. In that study, it was shown that their simulated ship trajectories had good agreement with experimentally measured tracks. This agreement motivated the following quantitative analysis of the experimental data to characterize the effects that wave impacts have on turning circle ship tracks. Our method involves describing the ship trajectories as sinusoids with time-varying means. We also estimate the uncertainty in the results from our analysis of the experimental measurements. The quantitative analysis shows overall agreement with Lin and Klamo (2010). New findings are also discussed such as changes in the distance and time to complete the maneuver as well as the speed and preferred directions of a drifting turning circle.


2020 ◽  
Vol 80 (11) ◽  
Author(s):  
June-Young Kim ◽  
Hyun-Chul Kim

AbstractWe investigate the electromagnetic transition form factors of the baryon decuplet to the baryon octet, based on the self-consistent SU(3) chiral quark-soliton model, taking into account the effects of explicit breaking of flavor SU(3) symmetry. We emphasize the $$Q^2$$ Q 2 dependence of the electromagnetic $$N\rightarrow \Delta $$ N → Δ transition form factors and the ratios of E2/M1 and C2/M1 in comparison with the experimental and empirical data. In order to compare the present results of the electromagnetic transition form factors of the $$N\rightarrow \Delta $$ N → Δ with those from lattice QCD, we evaluate the form factors with the pion mass deviated from its physical value. The results of the E2/M1 and C2/M1 ratios are in good agreement with the lattice data. We also present the results of the electromagnetic transition form factors for the decuplet to the octet transitions.


2015 ◽  
Vol 29 (32) ◽  
pp. 1550207 ◽  
Author(s):  
Hao Gong ◽  
Xiao-Xia Ruan ◽  
Hou-Rong Pang ◽  
Hong-Shi Zong

In this paper, taking into account the effect of the induced interaction, we calculate the energy of ultracold Fermi gases at unitarity in the framework of non-self-consistent T-matrix approximation (nTMA) above the critical temperature and compare the result with the experimental data and other theoretical calculation without induced interaction. Our calculated chemical potential is higher than the experimental data, but our calculated energy obtains a good agreement with Tokyo experiment for temperature range between [Formula: see text] and [Formula: see text].


2011 ◽  
Vol 702-703 ◽  
pp. 80-84
Author(s):  
Apu Sarkar ◽  
J.K. Chakravartty

The viscoplastic self-consistent (VPSC) formulation is by now a well established approach for simulating texture development and constitutive response during plastic forming of high and low-symmetry polycrystals. In this work we have used the VPSC approach to model the uniaxial tensile and compressive deformation characteristics of pure magnesium with random and extruded texture. We compare our results with experimental data and find that they are in good agreement with the available experimental evidence.


2016 ◽  
Vol 257 ◽  
pp. 203-210 ◽  
Author(s):  
Aleksandr A. Povzner ◽  
Anton N. Filanovich ◽  
Tatyana A. Nogovitsyna

Two computational approaches – a thermodynamic model based on results of ab initio calculations of the ground state and the self-consistent thermodynamic model have been applied to study thermal and elastic properties of iron monosilicide. It is shown that conventional DFT fails to reproduce experimental data for this strongly correlated compound. In addition, we have performed comparative analysis of anharmonicity of the acoustic and optical phonons in FeSi and their impact on the temperature dependencies of thermodynamic properties of FeSi.


2018 ◽  
Vol 182 ◽  
pp. 02109
Author(s):  
E. E. Saperstein ◽  
S. Kamerdzhiev ◽  
D. S. Krepish ◽  
S. V. Tolokonnikov ◽  
D. Voitenkov

Recent results of the description of quadrupole moments of odd semi-magic nuclei are briefly reviewed. They are based on the self-consistent theory of finite Fermi systems with account for the phonon-particle coupling (PC) effects. The self-consistent model for describing the PC effects was developed previously for magnetic moments. Account for the non-pole diagrams is an important ingredient of this model. In addition to previously reported results for the odd In and Sb isotopes, which are the proton-odd neighbors of even tin nuclei, we present new results for odd Bi isotopes, the odd neighbors of even lead isotopes. In general, account for the PC corrections makes the agreement with the experimental data significantly better.


2016 ◽  
Vol 25 (09) ◽  
pp. 1650065
Author(s):  
S. A. Alavi ◽  
V. Dehghani

The effect of using a temperature dependent pairing term in back-shifted Fermi-gas (BSFG) formula of nuclear level density has been studied. We have used the mean order parameter formula of modified Ginzburg–Landau (MGL) theory as a simple possible choice for temperature dependency of the pairing term. The level density and heat capacity of [Formula: see text]Mo have been calculated with this formalism and compared with the experimental data. We observed good agreement between the heat capacity of this model and the experimental data.


1973 ◽  
Vol 51 (19) ◽  
pp. 2092-2100 ◽  
Author(s):  
V. Krishna ◽  
N. Rumin

The photocurrent decay in high resistivity, n-type zinc-compensated silicon photoconductors has been measured in the temperature range 230–300 °K. The bulk portion of the decay can be resolved into two strongly temperature-dependent exponential components. A bulk recombination model based on two defect levels was used to analyze the experimental data. Reasonably good agreement between experiment and theory could be obtained only if the two centers were assumed to be the photoconductivity sensitizing, double acceptor Zn−3/2, and the V−3/2 level due to the vacancy which is also a double acceptor. In contrast, the measurements could only be partly explained with models in which the V−3/2 level was replaced by the E center, the lower zinc level Zn−1/2, or the A center. Moreover, unreasonable values for some of the material constants had to be assumed with these latter models.


2019 ◽  
Vol 204 ◽  
pp. 01022 ◽  
Author(s):  
Gennady Lykasov ◽  
Alexander Malakhov

The self-consistent approach based on similarity of inclusive spectra of hadrons produced in pp and AA collisions is reviewed. We present its modification due to the quark-gluon dynamics to describe the inclusive spectra of hadrons produced in pp collision as a function of the transverse momentum pt at mid-rapidity. The extension of this approach to analyze the pion pt-spectra produced in AA collision at high and middle energies and mid-rapidity is given. A satisfactory description of experimental data on these spectra in pp and AA collisions within the offered approach is shown.


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