Figure 3.

Streamline plots representing the maximum (coloured) and minimum (white) principal strain vectors in a finite deformation 2D plane-strain image-based finite-element model of the skin subjected to 20% in-plane compression (adapted from [20]). Grey arrows indicate the direction and location of the applied load. Streamlines, which are here overlaid over the undeformed geometry of the cross section of skin, allow direct visualization of load/strain paths within the skin as a result of any type of applied load. They are therefore very valuable, for example, to understand how deep and in which directions, loads are transmitted/deflected from the skin surface to/from the underlying layers in response to contact interaction with an external object.