title: Measurement of the uniaxial mechanical properties of rat skin using different stress-strain definitions.
abstract: OBJECTIVE
  The mechanical properties of skin tissue may vary according to the anatomical locations of a body. There are different stress-strain definitions to measure the mechanical properties of skin tissue. However, there is no agreement as to which stress-strain definition should be implemented to measure the mechanical properties of skin at different anatomical locations. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) are employed to determine the mechanical properties of skin tissue at back and abdomen locations of a rat body.
  
  
  METHODS
  The back and abdomen skins of eight rats are excised and subjected to a series of tensile tests. The elastic modulus, maximum stress, and strain of skin tissues are measured using three stress definitions and four strain definitions.
  
  
  RESULTS
  The results show that the effect of varying the stress definition on the maximum stress measurements of the back skin is significant but not when calculating the elastic modulus and maximum strain. No significant effects are observed on the elastic modulus, maximum stress, and strain measurements of abdomen skin by varying the stress definition. In the true stress-strain diagram, the maximum stress (20%), and elastic modulus (35%) of back skin are significantly higher than that of abdomen skin.
  
  
  CONCLUSIONS
  The true stress-strain definition is favored to measure the mechanical properties of skin tissue since it gives more accurate measurements of the skin's response using the instantaneous values.
authors: School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran; Tissue Engineering and Biological Systems Research Laboratory, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
authors: A
authors: A
authors: Karimi
authors: M
authors: M
authors: Navidbakhsh
mesh_terms: D000005:Abdomen / Q000502:physiology; D000818:Animals; D016880:Anisotropy; D001415:Back / Q000502:physiology; D055119:Elastic Modulus / Q000502:physiology*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012879:Skin Physiological Phenomena; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology*; D009626:Terminology as Topic
keywords: 2nd Piola-Kirchhoff stress; Almansi-Hamel strain; anatomical locations; mechanical properties; skin