Figure 4.

Summary of experimental results across all specimens. (A) Comparison of the obtained material parameter C₁₀ across the varying calculated strain rates (n = 44 for each strain rate). The higher strain rate regime (red) showed a stiffer response (paired sample two-tailed t-test, p-value$\ll 0.05$). (B) Shown is the comparison of the parameter κ across the varying calculated strain rates (n = 44 for each strain rate). The second strain rate regime (blue) showed lower κ values, indicating a more nonlinear response (paired sample two-tailed t-test, p-value$\ll 0.05$). (C) A closer look at stiffness values for the second strain rate regime is shown. For ${\dot{\mathrm{ϵ}}}_2<10s^{-1}$, stiffness values were lower (one-tailed t-test, p-value <0.05). (D) A closer look at κ for the second strain rate regime is shown. For ${\dot{\mathrm{ϵ}}}_2<10s^{-1}$, κ values were lower (one-tailed t-test, p-value <0.05). (E) No significance (n.s.) was found for stiffness when the maximum indentation depth exceeded 300 nm (multiple comparison Bonferroni test, p-value $\ll 0.05$). (F) No significance was found for κ as a function of maximum indentation (multiple comparison Bonferroni test, p-value $\ll 0.05$). To see this figure in color, go online.