Generalized strain probing of constitutive models

Youssef M.A. Hashash, Qingwei Fu, Jeremy Butkovich

Research output: Contribution to journalArticlepeer-review


Advanced material constitutive models are used to describe complex soil behaviour. These models are often used in the solution of boundary value problems under general loading conditions. Users and developers of constitutive models need to methodically investigate the represented soil response under a wide range of loading conditions. This paper presents a systematic procedure for probing constitutive models. A general incremental strain probe, 6D hyperspherical strain probe (HSP), is introduced to examine rate-independent model response under all possible strain loading conditions. Two special cases of HSP, the true triaxial strain probe (TTSP) and the plane-strain strain probe (PSSP), are used to generate 3-D objects that represent model stress response to probing. The TTSP, PSSP and general HSP procedures are demonstrated using elasto-plastic models. The objects resulting from the probing procedure readily highlight important model characteristics including anisotropy, yielding, hardening, softening and failure. The PSSP procedure is applied to a Neural Network (NN) based constitutive model. It shows that this probing is especially useful in understanding NN constitutive models, which do not contain explicit functions for yield surface, hardening, or anisotropy.

Original languageEnglish (US)
Pages (from-to)1503-1519
Number of pages17
JournalInternational Journal for Numerical and Analytical Methods in Geomechanics
Issue number15
StatePublished - Dec 25 2004


  • Constitutive models
  • Elasto-plasticity
  • Neural network
  • Probing
  • Soil behaviour
  • Visualization

ASJC Scopus subject areas

  • Computational Mechanics
  • Materials Science(all)
  • Geotechnical Engineering and Engineering Geology
  • Mechanics of Materials


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