Figure 3.
a,b. When cycled in regime I, collagen fibrils showed a hysteresis that reached steady-state within a few cycles both before (brown symbols) and after (blue symbols) 60-min relaxation. The dashed lines indicate a lapse in the data acquisition system. c. Inelastic strain before and after a 60 min relaxation interval, showing 50% strain recovery during the relaxation time. d. Elastic modulus insensitivity to cyclic loading before and after recovery. e. Energy dissipation reaching steady-state after only one cycle both before and after 60-min relaxation. For the data shown, the fibril diameter was 130 nm. Mean value of f. inelastic strain, g. elastic modulus E1, and h. hysteresis vs. cycle before and after relaxation computed from (5) cyclic tests conducted in regime I. The inelastic strain was normalized with the steady-state value in the 10th cycle, while the hysteresis was normalized with the value of the first cycle. Statistical data for inelastic strain and hysteresis are presented in normalized form because their absolute values depend on the applied λmax (see later Figure 6a). The error bars correspond to one standard deviation.