Identification of material parameters for the Vawter-Fung lung tissue constitutive model and assessment in human body model for impact loading

Abstract

The widely used Vawter-Fung (VF) lung tissue constitutive model, originally developed to model respiration, was assessed for applicability to impact human body models (HBMs). A review of the mechanical properties of lung tissue demonstrated existing parameter sets for the VF model encompassed a wide range of stiffness relative to experimental data. Consistent experimental datasets of lung tissue for uniaxial and biaxial tension were identified, and new parameters were fit to the VF model. A thoracic pendulum impact using a contemporary HBM was used to assess existing literature parameter sets, and the new parameters. The VF model parameters presented in this study produced uniaxial and biaxial tension response with improved hyperelastic response compared to experimental data and previously reported parameters. The VF surface tension component did not contribute substantially to the lung response in impact. The proposed VF model parameters were numerically stable for impact simulations and use in HBMs.