An Eshelbian homogenization solution for a coupled stress-diffusion moving interface problem in composites

2016 ◽  
Vol 01 (03n04) ◽  
pp. 1640011 ◽  
Author(s):  
Yang Zhang ◽  
Xian-Cheng Zhang ◽  
Shan-Tung Tu ◽  
Shaofan Li

In this work, we proposed a homogenization model to treat the coupled mechanical-diffusion moving interface problem. The Eshelbian homogenization method is applied to find the effective mechanical properties and diffusivity. On the one hand, the diffusion of solute elements would induce the formation of inclusion phases, affecting the mechanical equilibrium, properties and diffusivity. On the other hand, the stress condition will also have effects on the chemical potential and diffusion process. The coupling of the mechanical and diffusion processes were simulated using the present model, i.e., normal diffusion process and that with previous diffusion treatment. In the former case, thicknesses of outer and inner diffusion parts both increased with time. In the latter case, decomposition of the outer diffusion part might take place to maintain the growth of the inner part.

2019 ◽  
Vol 26 (10) ◽  
pp. 1950070
Author(s):  
YUWEN DING ◽  
XIAOCHUN CHEN ◽  
YA LIU ◽  
XUPING SU

Aluminized steels possess excellent corrosion resistance due to the formation of Al-Fe solution phases and intermetallic compounds in coatings. Ni was added to baths to further improve the corrosion resistance of the coatings at high temperature. Here, the role of Ni in the formation of coatings and the effect of diffusion process on the developing of coatings were investigated. 45 steels were immersed in Al-Ni baths (Al-1mass% Ni, Al-3mass% Ni, and Al-5mass% Ni) and diffusion-treated at 1023 and 1123[Formula: see text]K for 20, 40 and 100[Formula: see text]min, respectively. The coatings of samples were analyzed via scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) was further used to confirm the types of phases that formed during diffusion treatment. The formations of intermetallic coating layers were also analyzed via the diffusion path. More continuous Al3Ni layer and compact coating were obtained with diffusion treatment at 1023[Formula: see text]K for 40[Formula: see text]min.


2000 ◽  
Vol 32 (02) ◽  
pp. 426-445 ◽  
Author(s):  
Karl Sigman ◽  
Reade Ryan

A duality is presented for continuous-time, real-valued, monotone, stochastic recursions driven by processes with stationary increments. A given recursion defines the time evolution of a content process (such as a dam or queue), and it is shown that the existence of the content process implies the existence of a corresponding dual risk process that satisfies a dual recursion. The one-point probabilities for the content process are then shown to be related to the one-point probabilities of the risk process. In particular, it is shown that the steady-state probabilities for the content process are equivalent to the first passage time probabilities for the risk process. A number of applications are presented that flesh out the general theory. Examples include regulated processes with one or two barriers, storage models with general release rate, and jump and diffusion processes.


2006 ◽  
Vol 258-260 ◽  
pp. 447-452 ◽  
Author(s):  
Katell Derrien ◽  
Pierre Gilormini

When moisture uptake in a polymer is associated with swelling, it induces stresses which interact with the entire diffusion process. This coupling is addressed in this paper, which extends immediately to the diffusion of other fluids, like solvents. First, the generalized chemical potential is used to analyze the effect of stresses on the moisture capacity of polymers, and a relation is derived as a function of material parameters. Then, the interactions between stress and diffusion before saturation is reached, are explored. Various effects are predicted on the classical sorption test, such as an evolution of the boundary condition with time, and a sorptiondesorption hysteresis.


2000 ◽  
Vol 32 (2) ◽  
pp. 426-445 ◽  
Author(s):  
Karl Sigman ◽  
Reade Ryan

A duality is presented for continuous-time, real-valued, monotone, stochastic recursions driven by processes with stationary increments. A given recursion defines the time evolution of a content process (such as a dam or queue), and it is shown that the existence of the content process implies the existence of a corresponding dual risk process that satisfies a dual recursion. The one-point probabilities for the content process are then shown to be related to the one-point probabilities of the risk process. In particular, it is shown that the steady-state probabilities for the content process are equivalent to the first passage time probabilities for the risk process. A number of applications are presented that flesh out the general theory. Examples include regulated processes with one or two barriers, storage models with general release rate, and jump and diffusion processes.


2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Syeda Rabab Mudakkar

The aim of this work is to characterize one-dimensional homogeneous diffusion process, under the assumption that marginal density of the process is Gaussian. The method considers the forward Kolmogorov equation and Fourier transform operator approach. The result establishes the necessary characteristic equation between drift and diffusion coefficients for homogeneous and nonhomogeneous diffusion processes. The equation for homogeneous diffusion process leads to characterize the possible diffusion processes that can exist. Two well-known examples using the necessary characteristic equation are also given.


Author(s):  
Daisaku Soto ◽  
Hiromune Yokoki

Funafuti Atoll, where is located on the South Pacific (179° 11’ 50”E, 8° 31’ 16”S) is the capital atoll of Tuvalu. Most of residents live in Fongafale Island which is located in the eastern-side of the atoll. Lagoonal nearshore of Fongafale Island has a problem of nearshore pollutant caused by outflowing of untreated domestic wastewater. Sato et al.(2015) conducted the numerical simulation of the lagoonal flow field, and the particle advection simulation for estimating the pollutant transportation in the lagoon. However, the simulation was not included the diffusion process of pollutant. In this study, numerical simulation including advection-diffusion processes was conducted to understand the characteristics of the pollutant behavior in the lagoon of Funafuti Atoll.


Author(s):  
Òscar Garibo i Orts ◽  
Alba Baeza-Bosca ◽  
Miguel A. García-March ◽  
J. Alberto Conejero

Abstract Anomalous diffusion occurs at very different scales in nature, from atomic systems to motions in cell organelles, biological tissues or ecology, and also in artificial materials, such as cement. Being able to accurately measure the anomalous exponent associated to a given particle trajectory, thus determining whether the particle subdiffuses, superdiffuses or performs normal diffusion, is of key importance to understand the diffusion process. Also it is often important to trustingly identify the model behind the trajectory, as it this gives a large amount of information on the system dynamics. Both aspects are particularly difficult when the input data are short and noisy trajectories. It is even more difficult if one cannot guarantee that the trajectories output in experiments are homogeneous, hindering the statistical methods based on ensembles of trajectories. We present a data-driven method able to infer the anomalous exponent and to identify the type of anomalous diffusion process behind single, noisy and short trajectories, with good accuracy. This model was used in our participation in the Anomalous Diffusion (AnDi) Challenge. A combination of convolutional and recurrent neural networks was used to achieve state-of-the-art results when compared to methods participating in the AnDi Challenge, ranking top 4 in both classification and diffusion exponent regression.


1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.


1980 ◽  
Vol 41 (C6) ◽  
pp. C6-28-C6-31 ◽  
Author(s):  
R. Messer ◽  
H. Birli ◽  
K. Differt

1981 ◽  
Vol 17 (8) ◽  
pp. 528-541 ◽  
Author(s):  
Robert Crowningshield ◽  
Kurt Nassau

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