Fabric evolution within shear bands of granular materials and its relation to critical state theory

2010 ◽  
Vol 35 (18) ◽  
pp. 1918-1948 ◽  
Author(s):  
Pengcheng Fu ◽  
Yannis F. Dafalias
Keyword(s):  
Granular Materials ◽  
Critical State ◽  
Shear Bands ◽  
State Theory ◽  
Fabric Evolution ◽  
Critical State Theory

scholarly journals Fabric evolution and dilatancy within anisotropic critical state theory guided and validated by DEM

2020 ◽  
Vol 188-189 ◽  
pp. 210-222 ◽  
Author(s):  
Rui Wang ◽  
Yannis F. Dafalias ◽  
Pengcheng Fu ◽  
Jian-Min Zhang
Keyword(s):  
Critical State ◽  
State Theory ◽  
Fabric Evolution ◽  
Critical State Theory

scholarly journals Critical State Theory in Superconductors

2012 ◽  
Vol 51 (1R) ◽  
pp. 010109 ◽  
Author(s):  
Teruo Matsushita
Keyword(s):  
Critical State ◽  
State Theory ◽  
Critical State Theory

Sandstone compaction, grain packing and Critical State Theory

2007 ◽  
Vol 13 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Øystein Pettersen
Keyword(s):  
Critical State ◽  
State Theory ◽  
Grain Packing ◽  
Critical State Theory

Anisotropic Critical State Theory: Role of Fabric

2012 ◽  
Vol 138 (3) ◽  
pp. 263-275 ◽  
Author(s):  
Xiang Song Li ◽  
Yannis F. Dafalias
Keyword(s):  
Critical State ◽  
State Theory ◽  
Critical State Theory

scholarly journals Why energy lossless ferromagnetic materials can add energy losses onto type-II superconductors?

2021 ◽  
Author(s):  
Harold Ruiz ◽  
Muhammad Fareed
Keyword(s):  
Critical State ◽  
Electrical Current ◽  
State Theory ◽  
Ferromagnetic Materials ◽  
Hysteretic Behavior ◽  
Electromagnetic Properties ◽  
Ac Losses ◽  
Type Ii ◽  
Type Ii Superconductors ◽  
Critical State Theory

Abstract Understanding the physical coupling between the macroscopic electromagnetic properties of type II superconductors (SC) and soft ferromagnetic materials (SFM), is root for progressing onto the application of SC-SFM metastructures in scenarios such as magnetic cloaking, magnetic shielding, and loss free current transmission systems. However, in the latter case understanding the origin of the rise in the hysteresis losses of the superconductor by effect of the coupling with the SFM has historically resulted in a notable challenge, it because this rise in the AC losses is simply counterintuitive due to the fact that the SFM itself does not add magnetization losses to the system and furthermore, there is no evidence of electrical current sharing between these two materials. Thus, aimed to resolve this long-standing problem, in this paper, we present a semi-analytical model for monocore SC-SFM heterostructures of cylindrical cross-section and self-field conditions, showing the first known map of AC-losses for SC-SFM magnetically shielded wires, with magnetic relative permeabilities for the SFM ranging from mur=5 (NiZn ferrites) to mur =350000 (pure Iron). The distribution of current density and magnetic field inside the SC-SFM metastructure is shown in great detail, revealing a remarkable agreement with the intriguing magneto optical imaging observations that were originally questioning the validness of the critical state theory. In this sense, we have extended the critical state theory within its variational formalism, incorporating a multipole functional approach which allows the direct finding of the coupling terms between a SC current and a SFM sheath, proving that all reported phenomena for the self-filed hysteretic behavior of SC-SFM heterostructures can be understood within the classical critical state model without the need to recur to the ansatz of overcritical currents.

scholarly journals Prediction of Shear Localisation in Granular Materials based on a Critical State Non-coaxial Model

2019 ◽  
Vol 92 ◽  
pp. 16006 ◽  
Author(s):  
Hansini Mallikarachchi ◽  
Kenichi Soga
Keyword(s):  
Granular Materials ◽  
Plane Strain ◽  
Critical State ◽  
Progressive Failure ◽  
Shear Bands ◽  
State Parameter ◽  
Biaxial Compression ◽  
Compression Tests ◽  
Principal Axes ◽  
Shear Localisation

Experimental evidence indicates that the shear localisation acts as a precursor to the failure in biaxial compression tests of granular materials. Once formed they are persistent and lead to progressive failure of most geotechnical structures. It is generally accepted that the primary mode of deformation within these shear bands is simple shear which is accompanied by rotation of principal axes. Hence, the conventional plasticity theories based on the assumption of coaxility is not sufficient to describe the behaviour within those shear bands. This paper highlights the influence of the non-coaxility on the initiation and orientation of shear bands in both drained and undrained sand. The con-coaxial plasticity theory is integrated into a critical state constitutive model enriched with the state parameter concept. The model is capable of taking account of the variation of lode angle under plane strain condition. Numerical plane strain biaxial compression tests are conducted to observe the effect of non-coaxility on shear localisation. Bifurcation criteria based on the acoustic tensor are checked to predict the onset and inclination of the shear band. Predictions from the non-coaxial model are compared with those of coaxial model. The influence of the initial void ratio for the formation of shear bands is explored. Results are compared qualitatively with experimental observations.

Sign in / Sign up

Export Citation Format

Share Document