Fig. 7

Illustrative FEA example demonstrates the effect of aligned (top row of images) and staggered (bottom row of image) filaments on mechanical stiffness. The four views from left to right indicate the 3D model followed by side views (from left to right): before compression, after compression, and a von Mises stress colour map. The same force is applied to both scaffolds in FEA simulations. In the top scaffold, the filaments are aligned from top-to-bottom and therefore form a continuous pillar of polymer that resists compression. In contrast, the bottom scaffold has staggered filaments and the structure compresses by deformation at hinge points (located at regions of high-stress concentration in the von Mises stress plot). The scaffold collapses in a concertina manner by slightly bending filaments, which results in reduced stiffness versus the top scaffold with a continuous column of polymer