Premium
Instability of gradient dependent elasto‐viscoplasticity for clay
Author(s) -
Aifantis E. C.,
Oka F.,
Yashima A.,
Adachi T.
Publication year - 1999
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/(sici)1096-9853(19990825)23:10<973::aid-nag20>3.0.co;2-m
Subject(s) - viscoplasticity , constitutive equation , instability , boundary value problem , mechanics , finite element method , mathematics , equations of motion , geotechnical engineering , mathematical analysis , classical mechanics , geology , physics , thermodynamics
A gradient‐dependent viscoplastic constitutive model for water saturated clay is proposed to describe the strain localization phenomena and pattern formation during deformation. Second‐ and fourth‐order gradients of volumetric viscoplastic strain are introduced into the constitutive equations to account for the non‐local effects due to the motion of microstructures. A linear perturbation analysis is applied to this model. The instability of the government equations (i.e. the constitutive equations and the equations of motion for the clay skeleton and pore water) is discussed for both the one‐dimensional and the two‐dimensional situations. In addition, issues concerned with the formulation of boundary value problems by finite element analysis in relation to the formulation and the boundary conditions are presented. Copyright © 1999 John Wiley & Sons, Ltd.