title: Do mechanical properties of human fetal membrane depend on strain rate?
abstract: OBJECTIVE
  The objective of this study was to examine the effect of strain rate on the mechanical properties of human fetal membranes.
  
  
  METHODS
  Different strain rates were employed to quantify the stress-strain relation of the chorioamnion membrane. The mechanical properties of nine human amnion membranes, four collected from cesarean delivery and five collected from normal vaginal delivery, were examined in uniaxial tension tests under strain rates of 0.1, 1 and 10%/min.
  
  
  RESULTS
  Statistical analysis revealed significant (P < 0.05) correlation between the change in strain rate and the elastic modulus as well as failure strain of amnion samples. The rupture stress, though, did not show dependency on strain rates.
  
  
  CONCLUSIONS
  Human chorioamnion is strongly viscoelastic. By increasing the rate of the test, the stiffness of amnion increases considerably.
authors.affiliation: Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran.
authors.forename: Rahim
authors.initials: R
authors.lastname: Faturechi
authors.forename: Ata
authors.initials: A
authors.lastname: Hashemi
authors.forename: Nasser
authors.initials: N
authors.lastname: Fatouraee
mesh_terms: D000293:Adolescent; D000328:Adult; D005321:Extraembryonic Membranes / Q000502:physiology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D011247:Pregnancy; D013314:Stress, Mechanical; D055815:Young Adult
keywords: chorioamnion (fetal membrane); rupture stress; strain rate; uniaxial tension test; viscoelastic