Image study and fracturing processes of dry trabecular whale bone during fracture toughness tests

The fracture toughness and fracturing processes of dry trabecular whale vertebra were investigated in three-point bending tests with notched specimens. Images of the propagation of the fractures were captured with a High-Resolution and a High-Speed video cameras. It was observed that the fractures initiated at the notch tip and propagated by stages without branching, causing a load drop each time they propagated. Moreover, a strong correlation between the maximum vertical load and the slope of the load-displacement curves in the elastic regime was observed. Finally, the fracture toughness increased with the relative density of the specimens and was higher for the specimens cut radially than for those cut parallel to the axis of the vertebra.