|Title:||Active stress vs. active strain in mechanobiology: constitutive issues|
|Date:||Sunday 29th May 2011|
|Author(s) :||Ambrosi, D.; Pezzuto, S.|
|Abstract:|| Many biological tissues exhibit a non--standard continuum mechanics behavior:
they are able to modify their placement in absence of external loads.
The activity of the muscles is usually
represented in solid mechanics in terms of an active stress, to be added to the
standard one. A less popular approach is to introduce a multiplicative decomposition
of the tensor gradient of deformation in two factors: the passive and the active one.
Both approaches should satisfy due mathematical properties, namely frame indifference
and ellipticity of the total stress. At the same time, the constitutive laws should
reproduce the observed physiological behavior of the specific living tissue.
In this paper we focus on cardiac contractility.
We review some constitutive examples of active stress and active strain
taken from the literature and we discuss them in terms of precise mathematical and physiological
properties. These arguments naturally suggest new possible models.|
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Journal of Elasticity