Experimental compressive stress–strain curves. a) from female and male fracture: the parameters ultimate stress, σULT, Young’s modulus, E, are indicated. The energy to failure, WULT, corresponds to the area below the stress–strain curve. b) six stress–strain curves for male and female belonging to the three considered age-groups. Each curve represented corresponds to the experimental curve with ultimate stress value closest to the median value corresponding to each age-group.