Figure 7.

(a) The secant modulus, E_g, as a function of compressive displacement for a compressive velocity of 8 mm s⁻¹ calculated from equation (4.2) for orientations of the finger pad of 30° (blue diamonds) and 45° (red circles). (b) The secant modulus, E_g, as a function of the compressive force. The data are taken from the increasing region of (a). The full line (blue) and dashed line (red) are the best straight line fits to equation (4.7) for 30° and 45° orientations respectively, and used to obtain corresponding values for the Young's modulus, E_{0 g}, and the load coefficient of the secant modulus, β. (c) The Young's modulus, E_{0 g}, as a function of the compressive velocity. The full line (blue) and dashed line (red) are the mean values for 30° and 45° orientations, respectively. (d) The constraint coefficient, C, as a function of the compressive velocity, as calculated from the values of β, and R_g. The full line (blue) and dashed line (red) are the mean values for 30° and 45° orientations, respectively. (Online version in colour.)