title: A variational constitutive model for soft biological tissues.
abstract: In this paper, a fully variational constitutive model of soft biological tissues is formulated in the finite strain regime. The model includes Ogden-type hyperelasticity, finite viscosity, deviatoric and volumetric plasticity, rate and microinertia effects. Variational updates are obtained via time discretization and pre-minimization of a suitable objective function with respect to internal variables. Genetic algorithms are used for model parameter identification due to their suitability for non-convex, high dimensional optimization problems. The material behavior predicted by the model is compared to available tests on swine and human brain tissue. The ability of the model to predict a wide range of experimentally observed behavior, including hysteresis, cyclic softening, rate effects, and plastic deformation is demonstrated.
authors.affiliation: Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA. tamer@caltech.edu
authors.forename: Tamer
authors.initials: T
authors.lastname: El Sayed
authors.forename: Alejandro
authors.initials: A
authors.lastname: Mota
authors.forename: Fernando
authors.initials: F
authors.lastname: Fraternali
authors.forename: Michael
authors.initials: M
authors.lastname: Ortiz
mesh_terms: D004548:Elasticity; D020342:Finite Element Analysis; D008954:Models, Biological; D013314:Stress, Mechanical; D014783:Viscosity