Strain rate dependence of work of fracture tests on bone and similar tissues: Reflections on testing methods and mineral content effects.

This paper is concerned with the effect of different strain rate on the Work of Fracture (W) of various vertebrate mineralised tissues, controlling for the effect of mineral content and Young's modulus of elasticity. Using specimens of uniform shape and size values for the Work of Fracture of specimens tested at various deformation rates, and also the energy absorbed by notched specimens in impact, are reported. The results indicated that, of those tested, for most bone specimens the Work of Fracture measurements were constant like in the case for a 'material property'.

Notch sensitivity of mammalian mineralized tissues in impact.

The toughness of bone is an important feature in preventing it from fracturing. We consider the notch sensitivity in impact, and the associations between brittleness, notch sensitivity and post-yield energy absorption of mammalian mineralized tissues. Specimens of bone-like tissues covering a wide range of mineralization were broken, either notched or un-notched, in impact.

The effects of ageing and changes in mineral content in degrading the toughness of human femora.

Static toughness and impact strength of human cortical bone decline with age. This decline is strongly associated with an increase in the ash content of the bones but other factors, associated with age, are probably also responsible for the degradation of the bones' mechanical properties.

Effect of formaldehyde fixation on some mechanical properties of bovine bone.

The risk of infection of investigators working on the biomechanics of human bone from a variety of modern pathogens including the human immunodeficiency virus or the hepatitis B virus has increased recently. New safety procedures are needed to reduce that risk. The procedure we follow in our laboratory employs brief (< 3 h) fixation in formaldehyde, and we report here the effects it has on some mechanical properties of bovine bone.

Dependence of mechanical properties on fibre angle in narwhal tusk, a highly oriented biological composite.

The successful modelling of the mechanical properties of mineralized tissues depends critically on the knowledge of the off-axis behaviour of individual unidirectional lamellae. Information on this is lacking. In this work we attempt to rectify the situation.