Supports - Preventive Biomechanics - page 152

Fig. 4.1 Extra-corporal supports: a body/support system, and b foot/shoe sole; intra-corporal
supports, c knee joint/F RANKFURT I NLAY (supervision by Prof. Dr. H.-R. Ludwig, University of
Applied Sciences Frankfurt/Main, Germany), and d vascular wall/stent
4.2 Body Support Materials
4.2.1 Polymeric Soft Foams for Bedding Systems
Man-made cellular solids, such as soft polymeric foam, represent an important
class of engineering materials. This synthetic cellular material was first manu-
factured at the beginning of the twentieth century. Due to its unique properties it
has found application in many fields of industry, including the automotive and
aircraft industry, as well as in healthcare.
Body supports in the field of medical care, such as bedding, seating devices or
operation table overlays, as a rule contain soft polymeric foam components in the tissue-
support interface. Used in conjunction with long-term care or immobilized patients,
body support devices require special consideration, since material properties and
geometry play a major role in pressure sore development and discomfort related issues.
This section demonstrates the effects of open-cell soft polymeric foam supports on
tissue, using numerical simulation tools. After elucidating the microstructure of poly-
meric foam materials a phenomenological approach to mechanical foam character-
ization is described. Together with the subject matter presented in Sect. 3.4 , and based
on experimental testing, foam material parameters are derived by means of parameter
optimization. In this process long- and short-term foam behaviour is described.