Page 365 - Biomedical Engineering and Design Handbook Volume 1, Fundamentals

342 BIOMATERIALS

FIGURE 14.2 Classification of composite materials.

has a comparable degradation rate to such matrices. Ceramic matrices are used for their com-
pressive properties and bioactive possibilities but suffer from poor fracture toughness.

14.3.2 Fibers

A great majority of materials is stronger and stiffer in the fibrous form than in any other form. This
explains the emphasis on using fibers in composite materials design, particularly in structural appli-
cations, where they are the principal load-carrying component. Fibers have a very high aspect ratio
of length to diameter compared with particles and whiskers, and the smaller the diameter, the greater
is the strength of the fiber due to a reduction in surface flaws. Many properties of a composite are
determined by the length, orientation, and volume fraction of fibers of a given type.
Fibers are often manufactured as continuous filaments, with diameters in the range of 5 to
50 mm, and then they are arranged to produce tows, yarns, strands, rovings, mats, etc. These are used