Modelling fatigue damage accumulation in two-dimensional Voronoi honeycombs

Citation
G. Schaffner et al., Modelling fatigue damage accumulation in two-dimensional Voronoi honeycombs, INT J MECH, 42(4), 2000, pp. 645-656
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanical Engineering
Journal title
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
ISSN journal
0020-7403 → ACNP
Volume
42
Issue
4
Year of publication
2000
Pages
645 - 656
Database
ISI
SICI code
0020-7403(200004)42:4<645:MFDAIT>2.0.ZU;2-O
Abstract
Trabecular bone, a porous. cellular type of bone found at the ends of the l ong bones and within the vertebrae, is subject to cyclic compressive loadin g resulting from the activities of daily living. Such fatigue loading can r esult in fracture, especially in vertebrae of patients with osteoporosis. A s an initial step in understanding compressive fatigue of trabecular bone w e previously used finite-element analysis to model the progressive damage a nd failure of a simple, two-dimensional hexagonal honeycomb. In this study, the analysis is extended to a random, Voronoi honeycomb. Bending of the ce ll walls induces tensile stresses even when the overall loading is compress ive. The cell walls are assumed to have a distribution of crack lengths in their tensile zones. The cracks are assumed to grow according to a Paris la w and fail when the cracks reach 75% of the cell wall thickness. Failed cel l walls are removed from the structure, the stress distribution recalculate d and the next increment of fatigue loading are simulated. The Young's modu lus of the honeycomb is calculated after each cell wall failure. Overall fa ilure of the Voronoi structure is assumed to occur when the modulus is redu ced by 5%; further loading reduces the modulus sharply. The slope of the S- N curve for the Voronoi honeycomb is the same as that for the hexagonal hon eycomb. The model suggests that a random honeycomb is more sensitive to fat igue than a regular one. (C) 2000 Elsevier Science Ltd. All rights reserved .