Bone is more difficult to break than to split. Although this is well known, and many studies exist on the behaviour of long cracks in bone, there is a need for data on the orientation-dependent crack-growth resistance behaviour of human cortical bone that accurately assesses its toughness at appropriate size scales. Here, we use in situ mechanical testing to examine how physiologically pertinen...

Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. ...

Few studies have focused on a description of the fracture toughness properties of dentin in terms of resistance-curve (R-curve) behavior, i.e., fracture resistance increasing with crack extension, particularly in light of the relevant toughening mechanisms involved. Accordingly, in the present study, fracture mechanics based experiments were conducted on elephant dentin in order to determine su...

The aging-related deterioration of the fracture properties of bone, coupled with higher life expectancy, is responsible for increasing incidence of bone fracture in the elderly; consequently, an understanding of how these fracture properties degrade with age is essential. In this study, ex vivo fracture experiments have been performed to quantitatively assess the effect of age on human cortical...

Polymethylmethacrylate (PMMA) bone cement is a polymeric material that is widely used as a structural orthopedic material. However, it is not an ideal material for bone grafting due to its fragility. Carbon nanotubes (CNTs) have been introduced in order to reinforce PMMA resulting in a composite material which exhibits improved tensile properties, increased fatigue resistance and fracture tough...

Age-related deterioration of the fracture properties of bone, coupled with increased life expectancy, is responsible for increasing incidence of bone fracture in the elderly, and hence, an understanding of how its fracture properties degrade with age is essential. The present study describes ex vivo fracture experiments to quantitatively assess the effect of aging on the fracture toughness prop...

The purpose of this research is to determine the resistance to the stress corrosion cracking (SCC) of three unidirectional (pultruded) E-glass/polymer composites based on modified polyester, epoxy and vinyl ester resins. The composites have been subjected to a nitric acid solution of pH 1.2 in a newly designed four-point bend fixture. The stress corrosion process was initiated on the as supplie...

http://dx.doi.org/10.1016/j.actamat.2015.07.022 1359-6454/ 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Materials Science & Engineering, University of California, Berkeley, CA 94720, USA. E-mail address: [email protected] (R.O. Ritchie). 1 Intrinsic toughening mechanisms operate ahead of the crack tip to resistance to microst...

Despite decades of study, the atomic-scale mechanisms of fatigue crack growth remain elusive. Here we use the coupled atomistic–discrete dislocation method, a multiscale simulation method, to examine the influence of dislocation glide resistance on near-threshold fatigue crack growth in an aluminum alloy. The simulations indicate that the threshold increases with an increase in dislocation glid...

The fracture toughness and resistance-curve behavior of relatively coarse-scale, niobium/niobium aluminide (Nb/Nb3Al) laminated composites have been examined and compared to other Nb/Nb3Al composites with (in situ) Nb particulate or microlaminate reinforcements. The addition of high aspectratio Nb reinforcements, in the form of 20 vol. pct of 50to 250-mm-thick layers, was seen to improve the to...