title: Micromechanics of Sea Urchin spines.
abstract: The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material.
authors.affiliation: School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, New South Wales, Australia. n.tsafnat@unsw.edu.au
authors.forename: Naomi
authors.initials: N
authors.lastname: Tsafnat
authors.forename: John D
authors.initials: JD
authors.lastname: Fitz Gerald
authors.forename: Hai N
authors.initials: HN
authors.lastname: Le
authors.forename: Zbigniew H
authors.initials: ZH
authors.lastname: Stachurski
mesh_terms: D000825:Animal Structures / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D001315:Australia; D001696:Biomechanical Phenomena / Q000502:physiology; D002119:Calcium Carbonate; D003460:Crystallization; D004548:Elasticity; D020342:Finite Element Analysis; D007091:Image Processing, Computer-Assisted; D008954:Models, Biological; D012617:Sea Urchins / Q000033:anatomy & histology* / Q000502:physiology* / Q000648:ultrastructure; D013314:Stress, Mechanical; D054159:Torsion, Mechanical; D055114:X-Ray Microtomography
chemical_list: D002119:Calcium Carbonate