Time-dependent fracture toughness of cornea

J Mech Behav Biomed Mater. 2014 Jun:34:116-23. doi: 10.1016/j.jmbbm.2014.01.015. Epub 2014 Jan 29.

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.

Keywords: Cornea; Fracture toughness; Mechanical behavior; Rubber; Tissue mechanics; Trouser tear; Viscoelasticity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomechanical Phenomena
  • Cornea*
  • Corneal Injuries*
  • Materials Testing
  • Mechanical Phenomena*
  • Polymers
  • Stress, Mechanical
  • Swine
  • Time Factors

Substances

  • Polymers