Close-in blast resistance of large-scale auxetic re-entrant honeycomb sandwich panels

Abstract

The protection of critical infrastructure, including government buildings, airports, religious buildings, military buildings and military vehicles, which are at risk to blast loads, has become important due to increasing terrorist activities in recent years. Sacrificial cladding systems based on negative Poisson’s ratio core topologies have recently received more attention as a protective technology due to its excellent energy absorption capability. In this study, field blast tests were performed on metallic re-entrant honeycomb-cored sacrificial cladding systems as protective structures for steel plate structures. This study focused on the near-field blast loading conditions where liquid Nitromethane (NM) spherical charges were detonated in close proximity to the main structure. Two 6 mm thick mild steel plates and two steel plates protected with re-entrant honeycomb-cored sacrificial cladding systems were among the specimens tested. The proposed auxetic cladding system was fabricated from aluminium sheets using a novel in-house built folding machine. Numerical simulations were conducted utilising LS-DYNA software and the Blast Impact Impulse Model (BIIM). The results obtained from the numerical simulations are in good agreement with the experimental results. It was found that the deformation pattern of the sacrificial auxetic cladding system varies with the intensity of the blast loading, and there is a limit at which the proposed protective system ceases to effectively absorb the applied blast loading. The variation of negative Poisson’s ratio of the system with blast loading was studied. It was found that the auxetic cladding system could become a solid projectile leading to damage amplification for very close-range blast loads due to rapid densification of the auxetic core. The proposed cladding systems with narrow re-entrant angles performed well under blast loads due to relatively low stiffness of the panels. Finally, the optimisation study was performed for the protective system. Overall, the experimental and numerical results assure that auxetic-based cladding systems are suitable for applications requiring blast protection such as armoured vehicles and critical physical infrastructure but need to be carefully designed for the given blast threat to prevent overloading of the protected structures.

Prediction of the Response of Masonry Walls under Blast Loading Using Artificial Neural Networks

“…Finally, numerical solutions can be evaluated on advanced materials that can be used to protect masonry walls under blast actions. For instance, auxetic materials, with negative Poisson's ratio can be numerically tested by developing proper finite element models [45,46].…”

Experimental and finite element analyses of a 3D printed sandwich with an auxetic or non-auxetic core

“…A wide variety of two-dimensional auxetic and non-auxetic materials have been proposed, such as hexagonal, 6 chiral, 7 re-entrant 8 honeycombs and also three-dimensional metamaterials. 9 The development of additive manufacturing techniques has enabled the manufacture of increasingly complex structures.…”

Blast Resistance in Sandwich Structures Based on TPMS

“…Sandwich structures have received a lot of attention from researchers because of their good structural stability, high strength, and strong energy absorption capacity [1][2][3]. In the construction field, with various safety accidents, more and more buildings and structures are considering the blast resistance performance of the structure, and research [4][5][6] shows that sandwich panel structures can be effective in absorbing the blast energy. Now, the main sandwich structures are foam structures [7,8], honeycomb structures [9,10], corrugated structures [11], functionally graded structures [12,13], etc.…”