Biomedical Engineering Reference
In-Depth Information
Fig. 6.29 Tissue logarithmic shear strain LE
23
at skin level, fat-muscle interface and bone
surface as a function of time adjacent to the ischial tuberosity using E-BSS 1 and E-BSS 2 body
supports
Fig. 6.30 Tissue logarithmic
shear strain LE
23
at skin level
and bone surface as a
function of time adjacent to
the sacrum using E-BSS 1
and E-BSS 2 body supports
initiation of pressure sores in conjunction with both investigated foam materials
may, however, not be drawn since muscle tissue might be more susceptible to
deformation or hypoxia than fat tissue cells.
6.2.5.3 Elastic-Viscoelastic Body-Support-Systems (EVE-BSS)
The tissue-support interaction between the human model BoMo 0 and a homog-
enous mattress support (S
AF
material) is described whereby the viscoelastic
material behaviour of the foam support and elastic properties of the tissue material
properties are employed.
The interaction between BoMo 0 and a particular support may be conceptu-
alized as follows. During contact of the elastic model with the viscoelastic support,
the process is ''answered'' in a viscoelastic manner. Due to constant body loading
a simultaneous superposition of relaxation and creep phenomena takes place.
Definition of the stress paths: the contact interface stress between support and
tissue (without anatomical structures), Fig.
6.32
, and stress along two paths on skin
