Figure 1

Stress-strain and Young's modulus-strain curves. (a) Stress-strain curve from a 7.7 mm length sample of open cell PU foam (0.09 g.cm^-3) used to model very low density human cancellous bone and (b) the Young's modulus determined from it as the gradient of the curve. The yield point is defined by the point at which the Young's modulus decreases by 3% from its maximum value. The area under the stress-strain curve up to the yield point is defined as the energy absorbed to yield.