Distinct failure modes in bio-inspired 3D-printed staggered composites under non-aligned loadings

Abstract

The superior mechanical properties of biological materials originate in their complex hierarchical microstructures, combining stiff and soft constituents at different length scales. In this work, we employ a three-dimensional multi-materials printing to fabricate the bio-inspired staggered composites, and study their mechanical properties and failure mechanisms. We observe that bioinspired staggered composites with inclined stiff tablets are able to undergo two different failure modes, depending on the inclination angle. We find that such artificial structure demonstrates high toughness only under loading applied at relatively small angle to the tablets stacking direction, while for higher angles the composites fail catastrophically. This aspect of the failure behavior was captured experimentally as well as by means of the finite element analysis. We show that even a relatively simple failure model with a strain energy limiter, can be utilized to qualitatively distinguish these two different modes of failure, occurring in the artificial bio-inspired composites.

Bioinspired Compliance Grading Motif of Mortar in Nacreous Materials

“…It can be observed from Figure S2 that the load at which vertical mortar fails and that at which horizontal mortar fails increase with increase in elastic modulus of homogeneous mortar, leading to improved toughness of the nacreous system. During early stages of tensile loading, the vertical mortar takes more load relative to horizontal mortar and the tensile stress in the vertical bridges (mortar) further builds up with increase in load, eventually leading to failure of all vertically bridges at a load corresponding to first peak which is similar to observed behavior in natural nacre [3][4][5] .…”

Material characterisation of additively manufactured elastomers at different strain rates and build orientations

“…The existing material models of PolyJet elastomers in the literature are widely inconsistent as their time-dependency is often oversimplified [27,28] or entirely overlooked [29][30][31][32][33]. A recent study collected the shear modulus of several of the existing material models for T+ and reported a variation from 0.158 -0.330 MPa [27].…”

Fault-tolerant elastic–plastic lattice material

“…The fault tolerance response in these materials is thanks to their specific microstructure. They possess sacrificial links [4,5] or soft interfaces [6][7][8], which fail first, while the material remains intact at a macro scale. Similarly, some polymer materials possess distributed sacrificial links, failure of which does not destroy the material's integrity [9].…”