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A material model for inelastic rock deformation with spatial variation of pore pressure
Author(s) -
Smith M. B.,
Pattillo P. D.
Publication year - 1983
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/nag.1610070407
Subject(s) - yield surface , constitutive equation , plasticity , finite element method , quadratic equation , deformation (meteorology) , yield (engineering) , hardening (computing) , mechanics , strain hardening exponent , geotechnical engineering , structural engineering , materials science , mathematics , geometry , geology , engineering , physics , composite material , layer (electronics)
This paper sets forth the theoretical background and basic numerical expressions for the incorporation of elastic‐plastic constitutive equations for ductile rock into a finite element computer code. The derivation of an expression for the total strain rate is performed both for a total stress formulation and for a formulation that employs the concept of effective stress for inelastic behaviour. Specific expressions for the incremental strain rate are presented for the case of a porous material having a quadratic initial yield surface and observing the associated flow rule with a special hardening law for subsequent plastic deformation. A final section of the paper summarizes the expressions required to insert the quadratic yield surface model into a finite element code.