Press releases
Please quote Nature Materials as the source of these items.
February 2003
Bones that break like steel
Natural bone is sometimes described as the ultimate composite - a material that is lightweight, and yet stiff, strong and resilient. The human skeleton is more prone to injury than disease, but surprisingly little is known about the sequence of microscopic events that lead to bone fracture. In the March issue of Nature Materials, Robert Ritchie and colleagues demonstrate that, despite its brittle reputation, bone breaks in a similar way to ductile metals.
In the new experiments, at the University of California, Berkeley, the authors examine how microscopic cracks interact with the underlying bone structure. A simple, yet elegant, technique allows the authors to observe the very early stage of bone fracture, just after a small microcrack has formed, but before it has got out of control.
Using this technique, Ritchie and colleagues were able to investigate possible toughening mechanisms that have been proposed for bone, such as the build-up of 'microdamage'. As the authors write in their paper, "A mechanistic understanding of fracture in human bone is critical to predicting fracture risk associated with age and disease."
