Non-linear viscoelastic laws for soft biological tissues

The development of a conceptual framework to test different viscoelastic co nstitutive laws is presented. This framework has the advantage of satisfyin g a priori the thermodynamic restrictions and is valid for large deformatio ns. In addition, the different mechanical contributions are separated accor ding to the time scale of their effects. As an illustration of its ability to model the immediate, short time memory and long time memory contribution s, the framework is used to identify mechanical tests performed on human pa tellar tendons. The resulting viscoelastic law is then proposed to model th e soft biological tissues as these tissues present an important viscoelasti c behaviour. (C) 2000 Editions scientifiques et medicales Elsevier SAS.