Experimental characterization and numerical modelling of fracture processes in granite

Francesco Parisio, Ali Tarokh, Roman Makhnenko, Dmitri Naumov, Xing Yuan Miao, Olaf Kolditz, Thomas Nagel

Research output: Contribution to journalArticle

Abstract

Failure in brittle rock happens because micro-cracks in the crystal structure coalesce and form a localized fracture. The propagation of the fracture is in turn strongly influenced by dissipation in the fracture process zone. The classical theory of linear elastic fracture mechanics falls short in describing failure when the dissipation in the fracture process zone is non-negligible; thus, a non-linear theory should be employed instead. Here we present a study in which we explore the characteristics of the fracture process zone in granite. We have combined fracture tests on Adelaide black granite with acoustic emission detection and finite element analyses by using a non-local integral plastic-damage constitutive theory. We have further employed the theory of configurational mechanics to support our interpretation of the evolution of the fracture process zone with strong energy-based arguments. We demonstrate that the size of the fracture process zone is non-negligible and dissipative phenomena related to micro-cracking play an important role. Our results indicate this role should be assessed case by case, especially in laboratory-sized analyses, which mostly deflect from theories of both size-independent plasticity and linear elastic fracture mechanics. When strong non-linearities occur, we show that fracture energy can be correctly computed with the help of configurational mechanics and that complex numerical simulation techniques can substantially facilitate the interpretation of experiments designed to highlight the dominant physical mechanisms driving fracture.

Original languageEnglish (US)
Pages (from-to)102-116
Number of pages15
JournalInternational Journal of Solids and Structures
Volume163
DOIs
StatePublished - May 15 2019

Keywords

  • Crack-tip plasticity
  • Finite elements
  • Fracture mechanisms
  • Mechanical testing
  • OpenGeoSys

ASJC Scopus subject areas

  • Modeling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics

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