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SUMMARY:ENAC Seminar Series by Dr. Nicholas Anton Collins-Craft
DTSTART:20230516T160000
DTEND:20230516T170000
DTSTAMP:20260916T010539Z
UID:cafe4d25db144066a12516d812de37c104f0d00d6252ed28e6f0082f
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Nicholas Anton Collins-Craft \n16:00- 17:00 - Dr. Nichola
 s Anton Collins-Craft\nPostdoctoral researcher\, Centre Inria de l'Univer
 sité Grenoble Alpes\n\nNon-smooth mechanics for fracture propagation in g
 eomaterials\n\nModelling fracture propagation accurately and efficiently i
 s a critical issue across a wide variety of engineering disciplines\,not l
 east in brittle materials such as rock masses or permafrost. Of the wide v
 ariety of modelling techniques\, cohesive zone models are the most accurat
 e\, but are also correspondingly very numerically demanding. Intrinsic coh
 esive zone models are the most popular\, but their initial elasticity lead
 s to a range of non-physical behaviours that also cause severe numerical d
 ifficulties. While extrinsic cohesive zone models should avoid these behav
 iours\, in practice almost all models exhibit the same pathologies as intr
 insic models under complex loading such as impact by rockfalls. We use the
  techniques of non-smooth mechanics to formulate an extrinsic cohesive zon
 e model for mode I (opening mode) cracks that avoids entirely the patholog
 ical behaviours under all loading conditions\, while also including contac
 t behaviour in the formulation. After re-framing this model in dynamics\, 
 we are able to write the system as a linear complementarity problem (LCP).
  We show that this LCP is well-posed for quite large time-steps\, and we a
 re able to benefit from the efficient solution algorithms developed for th
 is class of problem. Some representative examples are explored with the mo
 del. We then pass to another model\, this time for both mode I and mode II
  (sliding mode)\, while including contact and Coulomb friction. This model
  once again avoids the pathological behaviours characteristic of other mod
 els\, and the dynamic formulation can be written as an LCP. We can show th
 at the solution of this LCP exists\, and once again benefit from the effic
 ient solution algorithms to examine some representative examples. Finally\
 , we examine some prospects for future extensions of this work\, the diffi
 culties to overcome\, and some applications to a variety of geomechanical 
 problems.\n\nShort bio: \n\nDr. Nicholas Collins-Craft obtained his Bache
 lor of Engineering in Civil Engineering with First Class Honours and the U
 niversity Medal from the University of Sydney in 2014. Starting in 2015\, 
 he undertook a joint PhD between the University of Sydney and ´Ecole nati
 onale des ponts et chauss´ees\, supervised by Professors Itai Einav\, Jea
 n Sulem and Ioannis Stefanou\, focused on the modelling of localisation in
  crushable granular media. This thesis was defended in November 2019. Foll
 owing this\, he undertook a postdoctoral period in the TRIPOP team at Inri
 a Grenoble\, working with Drs Vincent Acary and Franck Bourrier\, adapting
  techniques from non-smooth mechanics to the modelling of fracture. Since 
 September 2022\, he has been a Marie Sk lodowska-Curie Actions postdoctora
 l fellow\, on a joint project between Inria Grenoble and WSL/SLF Davos\, w
 orking with Drs Vincent Acary and Franck Bourrier and Professor Johan Gaum
 e\, on the topic of climate-change induced gravitational hazards.\n 
LOCATION:GC B1 10 https://plan.epfl.ch/?room==GC%20B1%2010
STATUS:CONFIRMED
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