title: Time-dependent fracture toughness of cornea.
abstract: The fracture and time-dependent properties of cornea are very important for the development of corneal scaffolds and prostheses. However, there has been no systematic study of cornea fracture; time-dependent behavior of cornea has never been investigated in a fracture context. In this work, fracture toughness of cornea was characterized by trouser tear tests, and time-dependent properties of cornea were examined by stress-relaxation and uniaxial tensile tests. Control experiments were performed on a photoelastic rubber sheet. Corneal fracture resistance was found to be strain-rate dependent, with values ranging from 3.39±0.57 to 5.40±0.48kJm(-2) over strain rates from 3 to 300mmmin(-1). Results from stress-relaxation tests confirmed that cornea is a nonlinear viscoelastic material. The cornea behaved closer to a viscous fluid at small strain but became relatively more elastic at larger strain. Although cornea properties are greatly dependent on time, the stress-strain responses of cornea were found to be insensitive to the strain rate when subjected to tensile loading.
authors.affiliation: Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ, UK.
authors.forename: Khaow
authors.initials: K
authors.lastname: Tonsomboon
authors.affiliation: Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ, UK.
authors.forename: Ching Theng
authors.initials: CT
authors.lastname: Koh
authors.affiliation: Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ, UK. Electronic address: mlo29@cam.ac.uk.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Oyen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003315:Cornea; D065306:Corneal Injuries; D008422:Materials Testing; D055595:Mechanical Phenomena; D011108:Polymers; D013314:Stress, Mechanical; D013552:Swine; D013997:Time Factors
chemical_list: D011108:Polymers
keywords: Cornea; Fracture toughness; Mechanical behavior; Rubber; Tissue mechanics; Trouser tear; Viscoelasticity