Effect of Strain Rate on the Bending Properties of Human Ribs

To fully characterize the mechanical behavior of bones under various loading conditions, it is important to determine the effect of strain rate on the load carrying capacit and fracture behavior of various members of our skeletal system. In this study embalmed human ribs were tested in a three-point bending mode under deformation rates of 0.05 mm/s, 0.5 mm/s, and 8 mm/s. Mechanical parameters such as maximum bending moment, maximum deformation, bending stiffness, and energy absorption capacity were determined. The maximum bending moment and stiffness showed an increase by 53 and 8 percent, respectively, at the highest rate of deformation compared to the lowest. The ultimate deformation and energy absorbed also increased by 26 and 66 per cent, respectively, in this range of deformation rate. This data confirms that bone is visco-elastic in nature and exhibits different mechanical properties that depend on the deformation rate.