A numerical study of bioinspired nacre-like composite plates under blast loading

Abstract

Abstract:In this paper, a multi-layered composite inspired by the hierarchical structure of nacre and made of layers of aluminium alloy AA 7075 bonded with toughened epoxy resin is introduced for blast resistant applications. The performance of the proposed nacre-like 3.3-mm and 5.4-mm thick composite plates, made of 1.1-mm thick AA 7075 layers, under localised impulsive loading was numerically studied. The epoxy material was modelled using user-defined interface cohesive elements that properly take into account both strength and toughness enhancements under compression. As compared to bulk plates, the improvement in blast resistance performance was numerically observed in the nacre-like plates, which required larger loads to reach the onset of failure. In addition, a reduction of the peak velocity and maximum deflection of the back face was observed for the nacre-like plates. This improvement is explained by the hierarchical structure facilitating a globalized energy absorption by inter-layer interlocking, delamination and friction.

Three-dimensional Voronoi model of a nacre-mimetic composite structure under impulsive loading

“…Other investigations have also found that nacre has tremendous ability to arrest crack propagation due to intrinsic and extrinsic toughening mechanisms that operate in front of and behind a developing crack tip, respectively [33]. Flores-Johnson et al [34] claimed that the performance of nacre-like plates under blast loading is explained by the hierarchical structure, which facilitates globalized energy absorption by interlayered interlocking and delamination.…”

Finite Element Analysis as a Method to Study Molluscan Shell Mechanics

“…Nacre may not be the most widespread ultrastructure in extant molluscs, but it is the most widely studied. Indeed, since the 1970s nacre has been a dominate material in the field of biomaterial research and has found several novel biomimetic uses, from improving impact resistance of armor to the creation of bone‐nacre composites for biomedical applications . The unique material properties of nacre are a product of several geometric parameters that have been elucidated with a combination of direct testing and finite element modeling over the past 15 years.…”

“…As mentioned in the introduction, one biomimetic application of nacre was the creation of tougher armor to resist extreme loading. One example of this is provided by Flores‐Johnson et al who compared finite element models of bulk plates and nacre based composite plates modeled with a degree of waviness and bonded with cohesive elements . The plates were subjected to an explosive load originating from above the geometric center of the plates, and the nacre‐like model showed increased resistance to failure compared to the bulk plates.…”

Influence of interfacial geometry on the energy absorption capacity and load sharing mechanisms of nacreous composite shells

“…A typical example where this is very important is under extreme loads, where the connection of a façade panel can fail and dislodge it from the supporting frame, as demonstrated by experiments conducted in [15]. Learning from nature can reduce the energy that is imparted from extreme loads before it reaches critical structures using composite materials [16,17]. However, we must first understand the mechanisms by which natural composites like nacre develop such high toughness from mainly brittle components.…”