Figure 2

Evolution of the local collagen fiber orientation of the isotropic skin sample due to repeated stretching and relaxation. Local fiber orientations are shown in false colors. Dashed lines indicate the minimum and maximum strains of the corresponding stretching cycle. (a) Collagen fiber orientation prior to deformation. The sample is stretched in the \(90^\circ\) direction as indicated by the arrow. (b) Local fiber orientation at maximum stretch of the first deformation cycle. The corresponding local orientations at maximum stretch of the second, third, and fourth deformation cycle are shown in (d), (f) and (h), respectively. (c) Local fiber orientation at maximum relaxation of the first deformation cycle. Similarly, local orientations at minimum stretch of the second, third, and fourth deformation cycle are shown in (e), (g) and (i), respectively. (j) Averaged force acting on the sample, measured by the force sensors as a function of the deformation cycle.