Strain rate-dependent viscohyperelastic constitutive modeling of bovine liver tissue.
The mechanical response of most soft tissue is considered to be viscohyperelastic, making the development of accurate constitutive models a challenging task. In this article, we present a constitutive model for bovine liver tissue that utilizes a viscous dissipation potential, and use it to model the response of bovine liver tissue at strain rates ranging from 0.001 to 0.04 s(-1). On the material modeling front of this study, the free energy is assumed to depend on the right Cauchy-Green deformation tensor, whereas a separate rate-dependent viscous potential is posited to characterize viscoelasticity. This viscous dissipation component is a function of the time rate of change of the right Cauchy-Green deformation tensor. On the experimental front, no-slip uniaxial compression experiments are conducted on bovine liver tissue at various strain rates. A numerical correction approach is used to account for the no-slip edge conditions, and the constitutive model is fit to the resulting corrected stress-strain data. The complete derivation of the material model, its implementation in the finite element software package ABAQUS, and a validation study are presented in this article. The results show that bovine liver tissue exhibits a strong strain-rate dependence even at the low strain rates considered here and that the proposed constitutive model is able to accurately describe this response.
Department of Biomedical Engineering, University of Memphis, 330 Engineering Technology Building, Memphis, TN 38152, USA. eroan@memphis.edu
Esra
E
Roan
Kumar
K
Vemaganti
D000818:Animals; D002417:Cattle; D004548:Elasticity; D008099:Liver / Q000502:physiology*; D008954:Models, Biological; D013314:Stress, Mechanical; D014783:Viscosity