title: Algorithms for a strain-based plasticity criterion for bone.
abstract: A range of stress-based plasticity criteria have been employed in the finite element analysis of the post-elastic behaviour of bone. There is some recognition now that strain-based criteria are more suitable for this material because they better represent its behaviour. Moreover, because bone yields at relatively isotropic strains, a strain-based criterion requires fewer material parameters unlike those required for a stress-based criterion. Based on a minimum and maximum principal strain criterion, a robust strain-based plasticity algorithm is developed. As the criterion comprises six piecewise linear surfaces in principal strain space, it has a number of singular regions. Singularity indicators are developed to direct the algorithm to make appropriate plastic corrector returns when singularity regions are encountered. The developed algorithms permit a plastic corrector to be achieved in a single iterative step in all cases. A range of benchmark tests are developed and conducted after implementing the algorithm in a finite element package. These tests show that the constitutive behaviour is as expected.
authors.affiliation: School of Engineering, The University of Edinburgh, King's Buildings, Edinburgh, EH9 3JL, UK. pankaj@ed.ac.uk
authors.forename: Pankaj
authors.initials: P
authors.lastname: Pankaj
authors.forename: Finn E
authors.initials: FE
authors.lastname: Donaldson
mesh_terms: D000465:Algorithms; D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D013312:Stress, Physiological / Q000502:physiology*