ABSTRACT
Bone is viscoelastic, meaning that it can behave as a ductile or brittle material depending on the velocity, rate, duration, and direction of the force(s) to which it is subjected. Ductile materials can absorb more energy prior to failure than brittle materials. Figure 15.1 contrasts the behavior of a ductile versus brittle material under similar loading. A ductile material undergoes a period of elastic deformation, during which the material will assume its original structure/shape if the load is removed. If the loading persists, the material undergoes plastic deformation. If the load is removed following plastic deformation, the material will not return to its original shape, but instead will remain permanently deformed. With continued loading, the material will fail. Brittle materials, on the other hand, undergo very little if any plastic deformation prior to failure. A mild steel provides an excellent example of a ductile material, and glass, a brittle material.
