Structurally motivated damage models for arterial walls. Theory and application - Modeling of Physiological Flows - page 140

6
Structurally motivated damage models for
arterial walls. Theory and application
Anne M. Robertson, Michael R. Hill, and Dalong Li
6.1 Introduction
The mechanical integrity of the arterial wall is vital for the health of the individual.
This integrity is in turn dependent on the state of the central load bearing components
of the wall: collagen fibres, elastic fibres and smooth muscle. Of these, the elastic fi-
bres, composed largely of the protein elastin, are viewed as responsible for the highly
elastic behaviour of the wall at low loads [92]. The collagen fibres are recruited un-
der increasing extension, leading to a highly nonlinear behaviour of the arterial wall
[117]. They are responsible for the structural integrity of the wall at elevated phys-
iological loads. Changes in the quantity, distribution, orientation and mechanical
properties of these components (the microstructure) are known to occur as part of a
healthy response to changing stimuli (e.g. growth and remodelling) as well as during
pathological and damage processes in disease and aging. For example, degradation
of the elastic fibres is linked to pathological conditions including cerebral aneurysms
[12, 15, 20, 65], dissection aneurysms [101], arteriosclerosis [11, 44, 86, 113, 114],
and complications from balloon angioplasty [84]. Age related arterial stiffening is
attributed to degradation of the elastic fibres, possibly from fatigue failure [11, 30].
The subject of arterial damage is addressed in Sect. 6.4.
The mechanical behaviour of the arterial wall is modelled from several perspec-
tives. Phenomenological models are based on bulk measurements of the mechanical
response of the arterial wall, while structural theories directly integrate information
Anne M. Robertson ( )
University of Pittsburgh, Pittsburgh, PA 15261 USA
e-mail: [e-mail]
Michael R. Hill
University of Pittsburgh, Pittsburgh, PA 15261 USA
e-mail: [e-mail]
Dalong Li
Ansys Inc., Canonsburg, PA USA
e-mail: [e-mail]