Comportamento à fractura do tecido ósseo cortical sob solicitações de modo misto I+II.

Bone fractures are common events as a result of accidental loading, fatigue and diseases. Hence, the evaluation of fracture properties of cortical bone is an important research topic with relevant impact on public health. However, this is a very challenging endeavor because bone tissue is a composite material with heterogeneous, anisotropic and hierarchical microstructure. Recently, Fracture Mechanics (FM) has emerged as an essential method for assessing the fracture risk of bone. However, the majority of FM applications in the context of bone are based on Linear Elastic FM theory, which is inadequate taking into consideration the material behaviour. In fact, as a result of its complex microstructure and composition, a non-negligible Fracture Process Zone (FPZ) develops. The FPZ is the region in the vicinity of the crack tip where several phenomena like microcracking, crack deviation and fibre bridging take place. These issues and the natural limitation associated to the size of specimens possible to get in bone, render difficult the definition of appropriate tests for bone fracture characterization. On the other hand, the majority of the studies available in literature is dedicated to mode I loading, though it is recognized that in daily activities mixed mode (MM) loading prevails. The main objective of this project concerns the definition of adequate tests for bone fracture characterization under MM I+II loading.