title: A model of lung parenchyma stress relaxation using fractional viscoelasticity.
abstract: Some pulmonary diseases and injuries are believed to correlate with lung viscoelasticity changes. Hence, a better understanding of lung viscoelastic models could provide new perspectives on the progression of lung pathology and trauma. In the presented study, stress relaxation measurements were performed to quantify relaxation behavior of pig lungs. Results have uncovered certain trends, including an initial steep decay followed by a slow asymptotic relaxation, which would be better described by a power law than exponential decay. The fractional standard linear solid (FSLS) and two integer order viscoelastic models - standard linear solid (SLS) and generalized Maxwell (GM) - were used to fit the stress relaxation curves; the FSLS was found to be a better fit. It is suggested that fractional order viscoelastic models, which have nonlocal, multi-scale attributes and exhibit power law behavior, better capture the lung parenchyma viscoelastic behavior.
authors.affiliation: University of Illinois at Chicago, Chicago, IL 60607, USA. Electronic address: daizoujun@gmail.com.
authors.forename: Zoujun
authors.initials: Z
authors.lastname: Dai
authors.affiliation: University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Peng
authors.affiliation: University of Central Florida, Orlando, FL 32816, USA.
authors.forename: Hansen A
authors.initials: HA
authors.lastname: Mansy
authors.affiliation: Nemours Children's Hospital, Orlando, FL 32827, USA.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Sandler
authors.affiliation: University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Royston
mesh_terms: D000818:Animals; D004548:Elasticity; D005260:Female; D016014:Linear Models; D008168:Lung / Q000502:physiology*; D008954:Models, Biological; D013312:Stress, Physiological / Q000502:physiology*; D013552:Swine; D055682:Viscoelastic Substances; D014783:Viscosity
chemical_list: D055682:Viscoelastic Substances
keywords: Fractional viscoelasticity; Lung parenchyma; Stress relaxation