Internship - Non-smooth modeling of rockfall trajectory accounting for block interaction with trees.

February 26, 2023
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2023-05730 - Internship - Non-smooth modeling of rockfall trajectory accounting for block interaction with trees.

Contract type : Internship

Level of qualifications required : Graduate degree or equivalent

Fonction : Internship Research

About the research centre or Inria department

The Inria Grenoble - Rhône-Alpes research center groups together almost 600 people in 22 research teams and 7 research support departments.

Staff is present on three campuses in Grenoble, in close collaboration with other research and higher education institutions (University Grenoble Alpes, CNRS, CEA, INRAE, …), but also with key economic players in the area.

Inria Grenoble - Rhône-Alpes is active in the fields of high-performance computing, verification and embedded systems, modeling of the environment at multiple levels, and data science and artificial intelligence. The center is a top-level scientific institute with an extensive network of international collaborations in Europe and the rest of the world.


TRIPOP is a joint research team of Inria Grenoble Rhône-Alpes and of the Laboratoire Jean Kuntzmann and started in January 2018 as a follow up of the BIPOP team. The team is mainly concerned by the modeling, the simulation and the control of nonsmooth dynamical systems. Nonsmooth dynamics concerns the study of the time evolution of systems that are not smooth in the mathematical sense, {em i.e.}, systems that are characterized by a lack of differentiability, either of the mappings in theirs formulations, or of theirs solutions with respect to time. In mechanics, the main instances of nonsmooth dynamical systems are multibody systems with Signorini's unilateral contact, set-valued (Coulomb-like) friction and impacts, or in continuum mechanics, ideal plasticity, fracture or damage. The members of the team have a long experience of nonsmooth dynamics modeling together with the development of simulation software. With the integration of Franck Bourrier as a new research member, a part of the activities of the theme is now focused in rockfall trajectory modeling and natural hazard mitigation.


Rockfall is one of the most common natural hazards in mountainous regions. The assessment of this hazard, related with block detachment conditions and propagation, is essential for mitigation strategies that include hazard zones determination and protection structures design.

Block trajectory simulation models are routinely used for the quantitative assessment of rockfall hazard. The recent block propagation models explicitly account for the fragment shape, using either regularized Discrete Element Methods (DEM) or on nonsmooth contact dynamics methods. These models currently only integrate the effects of forest in a simplified way . In particular, they do not explictly model the deformation and the breakage of the tree due to the impacts of blocks.

The objective of this internship is to integrate into a block propagation model the response of trees, modelled as elastoplastic deformable beams using the Finite Element Method in the framework of nonsmooth mechanics, to the impact of blocks. The block propagation model, based on Siconos code 3 developed in Tripop team, has already been extensively tested. In addition, the theoretical bases of the model of the trees response to impact have beenset up in two PhD works 1,2 and a Python prototype of the model has already been built.

keywords : Computational Mechanics, Contact and Impact Mechanics, Finite Element Method, Rockfall trajectory, Natural Hazard mitigation.

1 Toe D. (2016) Etude de l'influence des peuplements forestiers de type taillis sur la propagation des blocs rocheux, PhD thesis, UGA. 2 Viano B. (2022) Approche non régulière pour la modélisation des structures élastoplastiques sous impact, PhD thesis, UGA. 3 https: //

Main activities

The internship will therefore be dedicated to the numerical implementation of the Python prototype into Siconos code after a initial learning phase of detailed understanding of the Python prototype and of Siconos architecture.

Name of the supervisor and co-supervisor :

  • Vincent Acary (INRIA, Tripop)
  • Franck Bourrier (INRIA, Tripop and UR ETNA, Inrae)
  • Sylvain Dupire (UR LESSEM, Inrae)
  • Skills

    The candidate should have competences in numerical modeling and mechanics. A subsequent background in software development, in particular in C++, is also mandatory. The candidate also has to be motivated by applied research in collaboration with researchers from different disciplines.

    Benefits package
  • Subsidized meals
  • Partial reimbursement of public transport costs
  • Professional equipment available (videoconferencing, loan of computer equipment, etc.)
  • Social, cultural and sports events and activities
  • Remuneration

    Minimum legal gratification

    General Information
  • Theme/Domain : Numerical schemes and simulations Scientific computing (BAP E)

  • Town/city : Montbonnot

  • Inria Center : Centre Inria de l'Université Grenoble Alpes
  • Starting date : 2023-03-01
  • Duration of contract : 5 months
  • Deadline to apply : 2023-02-26
  • Contacts
  • Inria Team : TRIPOP
  • Recruiter : Acary Vincent / [email protected]
  • About Inria

    Inria is the French national research institute dedicated to digital science and technology. It employs 2,600 people. Its 200 agile project teams, generally run jointly with academic partners, include more than 3,500 scientists and engineers working to meet the challenges of digital technology, often at the interface with other disciplines. The Institute also employs numerous talents in over forty different professions. 900 research support staff contribute to the preparation and development of scientific and entrepreneurial projects that have a worldwide impact.

    Instruction to apply

    Applications must be submitted online on the Inria website. Processing of applications sent by other channels is not guaranteed.

    Defence Security : This position is likely to be situated in a restricted area (ZRR), as defined in Decree No. 2011-1425 relating to the protection of national scientific and technical potential (PPST).Authorisation to enter an area is granted by the director of the unit, following a favourable Ministerial decision, as defined in the decree of 3 July 2012 relating to the PPST. An unfavourable Ministerial decision in respect of a position situated in a ZRR would result in the cancellation of the appointment.

    Recruitment Policy : As part of its diversity policy, all Inria positions are accessible to people with disabilities.

    Warning : you must enter your e-mail address in order to save your application to Inria. Applications must be submitted online on the Inria website. Processing of applications sent from other channels is not guaranteed.

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