INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING Int. J. Numer. Meth. Engng 2010; 82:843–867 Published online 23 November 2009 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/nme.2788 A mesh adaptation framework for dealing with large deforming meshes Ga¨ etan Comp` ere 1, ∗, † , Jean-Franc ¸ois Remacle 1,2 , Johan Jansson 3 and Johan Hoffman 3 1 Department of Civil Engineering, Universit´ e catholique de Louvain, Place du Levant 1, 1348 Louvain-la-Neuve, Belgium 2 Center for Systems Engineering and Applied Mechanics (CESAME), Universit´ e catholique de Louvain, 1348 Louvain-la-Neuve, Belgium 3 Royal Institute of Technology, Computational Technology Laboratory, Stockholm, Sweden SUMMARY In this paper, we identify and propose solutions for several issues encountered when designing a mesh adaptation package, such as mesh-to-mesh projections and mesh database design, and we describe an algorithm to integrate a mesh adaptation procedure in a physics solver. The open-source MAdLib package is presented as an example of such a mesh adaptation library. A new technique combining global node repositioning and mesh optimization in order to perform arbitrarily large deformations is also proposed. We then present several test cases to evaluate the performances of the proposed techniques and to show their applicability to fluid–structure interaction problems with arbitrarily large deformations. Copyright 2009 John Wiley & Sons, Ltd. Received 15 September 2009; Accepted 2 October 2009 KEY WORDS: mesh adaptation; local modifications; large deformations; open source; fluid–structure interaction 1. INTRODUCTION Mesh motion due to a moving interface or boundary is an essential component in many modern finite element procedures [1–3], with applications in many domains, and in particular the numerical computation of fluid–structure interactions (FSI). ∗ Correspondence to: Ga¨ etan Comp` ere, Department of Civil Engineering, Universit´ e catholique de Louvain, Place du Levant 1, 1348 Louvain-la-Neuve, Belgium. † E-mail: gaetan.compere@uclouvain.be Contract/grant sponsor: Fonds National de la Recherche Scientifique Contract/grant sponsor: The Swedish Foundation for Strategic Research Contract/grant sponsor: European Research Council Copyright 2009 John Wiley & Sons, Ltd.