Hyper-viscoelastic response of perfused liver under dynamic compression and estimation of tissue strain thresholds with a liver finite element model

A liver Finite Element (FE) model with hyper‐viscoelastic properties was developed. Hyper‐elastic and rate‐dependent characteristics were modeled with an Ogden rubber material model. Such characteristics were validated against an original series of porcine ex-sanguinated livers under quasi‐static and dynamic compression experiments. The applicability of the validated liver FE model was evaluated against a series of compression tests with porcine perfused livers to model nearly in vivo conditions. The regions where the FE model showed highest strain concentrations corresponded with the regions where perfused livers tested under dynamic loading sustained tissue damage. Based on this correspondence, ultimate strains for hepatic parenchyma and membrane were estimated by comparing strain patterns of the FE model with damaged conditions of the tested livers.