Alain Curnier | EPFL Graph Search

Né en 1948, Alain CURNIER obtint un diplôme d'ingénieur en mécanique de l'Institut National des sciences appliquées (INSA) de Lyon en 1972, puis un doctorat en mécanique des structures de l'Université de Californie à Berkeley en 1978.

Il acquit un premier savoir faire comme ingénieur de recherche chez Engineering System International à Paris de 1978 à 1981 sur des projets de dynamique des structures et de mécanique des matériaux. Il rejoignit le Laboratoire de mécanique appliquée de l'EPFL en 1981 où il fut successivement nommé chargé de cours en 1985, adjoint scientifique en 1987 et professeur titulaire en 1998. Il a pris sa retraite en 2013 et a été nommé professeur honoraire.

Ses domaines de recherche et d'enseignement furent principalement la mécanique des solides et la mécanique des contacts, la simulation numérique et l'identification expérimentale. Il a notamment conçu des lois de comportement originales en élasticité, viscoélasticité et élastoplasticité des matériaux composites et des tissus vivants en grandes déformations, ainsi que des lois tribologiques de contact unilatéral, adhésion, lubrification et frottement. Il a développé le logiciel d'analyse mécanique non linéaire des solides et des contacts TACT.

M. Curnier a été professeur invité dans plusieurs universités ou institutions.

Il est l'auteur d'une cinquantaine de publications dont un premier livre sur les Méthodes numériques en mécanique des solides aux PPUR (1993-2000), traduit en anglais en Computational methods in solid mechanics chez Kluwer (1994), un second livre intitulé Mécanique des solides déformables, vol 1 Cinématique, dynamique, énergétique, aux PPUR (2005), vol 2 Elasticité, viscosité, plasticité (en préparation) et de deux chapitres de livres sur la Mécanique des contacts chez Springer (1999 et 2000).

A 1D elastic plastic damage constitutive law for bone tissue

Alain Curnier, Daniel Garcia

Motivated by applications in orthopaedic and maxillo-facial surgery, the mechanical behaviour of cortical bone in cyclic overloads at physiological strain rates is investigated. To this end, a new one-dimensional rate-independent constitutive model for compact bone is proposed to simulate the damage accumulation occurring during tensile or compressive overloading. We adopted a macroscopic and phenomenological description of the mechanics of cortical bone. The mathematical formulation of the model is established within the framework of generalized standard materials and is based on the definition of three internal state variables: a tensile and a compressive damage variable that represent the microcrack density and a residual strain variable that represents the permanent strain associated with the sliding behaviour of these microcracks. Distinct damage threshold stresses are used in tension and compression. As the macroscopic mechanical behaviour of bovine cortical bone is very similar to that of human cortical bone and of much easier access, we first achieved the validation and identification of the material constants of the constitutive laws in tension using new uniaxial experimental results of bovine compact bone of our own. With adequate original hardening rules, the constitutive model is able to reproduce the main features of cortical bone behaviour under arbitrary cyclic tensile and compressive loadings. The proposed algorithm applies for the first time three distinct projections based on the relationship between the three internal variables and criteria. The predicted stress-strain curves exhibit a damaged reloading which is collinear with the origin as many cyclic overloading experiments on cortical bone have shown. Note that as our model was identified for physiological strain rates, it hardly can be applied in high strain rate situations like the ones involved in impact studies.

2010

Experimentation on adhesion of epoxy

Alain Curnier, Aleksandar Sekulic

In a recent article (Sekulic and Curnier (2007) [1]), an original axisymmetric epoxy-stamp on glass-disc specimen, which exhibits stable debonding, was presented for identifying the adhesive properties between epoxy and glass, namely interface debonding energy omega, adhesion peak stress pi(n) and debonding rupture gap gamma(n).

2010

A three-dimensional elastic plastic damage constitutive law for bone tissue

Alain Curnier, David Garcia

Motivated by mechanical analysis of bones and bone-implant systems, a 3D constitutive law describing the macroscopic mechanical behaviour of both cortical and trabecular bone in cyclic (not fatigue) overloads is developed. The proposed model which mathematical formulation is established within the framework of generalized standard materials accounts for three distinct material evolution modes where elastic, plastic and damage aspects are closely related. The anisotropic elasticity of bone is described by a morphology-based model and distinct damage behaviour in tension and compression by a halfspacewise generalized Hill criterion. The plastic criterion is based on the intact elastic compliance tensor. The algorithm applies three distinct projections based on the relationship between the internal variables and criteria. Their respective consistent tangent operators are presented. Numerical resolutions of several boundary value problems and a biomechanical application are presented to illustrate the potential of the constitutive model and demonstrate the expected quadratic convergence of the algorithm.

Springer Verlag2009

A 1D elastic plastic damage constitutive law for bone tissue

Alain Curnier, Daniel Garcia

2010