Whereas fatigue is
generally considered as a major mechanism of failure in metallic and polymeric
components, brittle materials, such as ceramics, are also susceptible to
premature failure under cyclic loads, although the mechanisms of fatigue damage
are quite distinct to those encountered in ductile materials. In this
presentation, an understanding of the fracture of such brittle and ductile
materials is used to address similar issues with (nearly) ÒnanoÓ and ÒbioÓ
materials.Specifically, the failure
of Òsmall-volumeÓ structures for MEMS, involving the high-cycle fatigue of
micron-scale silicon films, and the fracture and fatigue properties of ÒhardÓ
mineralized tissue - bone and dentin (the major constituent in teeth) - are
examined with an objective of isolating mechanisms.In particular, the relationship between the
aging of bone and teeth and in vivo
mechanical damage will be considered.