Finite Element Analysis of the Ballistic Impact on Auxetic Sandwich Composite Human Body Armor

Abstract

In this study, the ballistic impact behavior of auxetic sandwich composite human body armor was analyzed using finite element analysis. The auxetic core of the armor was composed of discrete re-entrant unit cells. The sandwich armor structure consisted of a front panel of aluminum alloy (Al 7075-T6), UHMWPE (sandwich core), and a back facet of silicon carbide (SiC) bonded together with epoxy resin. Numerical simulations were run on Explicit Dynamics/Autodyne 3-D code. Various projectile velocities with the same boundary conditions were used to predict the auxetic armor response. These results were compared with those of conventional monolithic body armor. The results showed improved indentation resistance with the auxetic armor. Deformation in auxetic armor was observed greater for each of the cases when compared to the monolithic armor, due to higher energy absorption. The elastic energy dissipation results in the lower indentation in an auxetic armor. The armor can be used safely up to 400 m/s; being used at higher velocities significantly reduced the threat level. Conversely, the conventional monolithic modal does not allow the projectile to pass through at a velocity below 300 m/s; however, the back face becomes severely damaged at 200 m/s. At a velocity of 400 m/s, the front facet of auxetic armor was destroyed; however, the back facet was completely safe, while the monolithic panel did not withstand this velocity and was completely damaged. The results are encouraging in terms of resistance offered by the newly adopted auxetic armor compared to conventional monolithic armor.

Auxetics and FEA: Modern Materials Driven by Modern Simulation Methods

“…In a recent study, the ballistic impact behaviour of auxetic sandwich composite human body armour was analysed using FEA. Numerical simulations showed improved indentation resistance and higher energy absorption in the auxetic armour compared to conventional monolithic armour [61]. Similar auxetic sandwich panels were also considered for blast protection in military vehicles, showcasing superior performance both in terms of being more lightweight and offering better protection compared to the solid plate [290].…”

“…This may be attributed, at least in part, to the complex geometries that auxetic structures have, the lack of availability of "off the shelf" auxetic materials on a large scale, issues relating to sustainability, practical drawbacks of physical prototyping (prototypes are expensive, unsustainable, difficult to manufacture, and just a general burden to test) as well as ethical issues which may arise in certain experimental testing in real applications where auxetics could be truly needed (e.g., stents [53,54]). As a consequence, researchers have resorted to rapidly developing research protocols based on computer simulation and numerical analysis, often using experimental results and analytical studies to verify the numerical results obtained [9, [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69].…”

Nonlinear Constitutive and Mechanical Properties of an Auxetic Honeycomb Structure

“…As a lightweight material structure, the honeycomb structure not only has high specific stiffness and specific strength, but also has good thermal insulation, vibration isolation, energy absorption and impact resistance [1,2]. It has been widely used in aerospace, vehicles [3], construction [4], bridges and national defense. The honeycomb sandwich structure is composed of periodically arranged honeycomb cells as the core layer and a thin skin.…”

Optimization of Process Parameters in Friction Stir Welding of Aluminum 5451 in Marine Applications

“…Aluminum and its alloys are frequently utilized in the design of complex marine construction such as hulls and deck panels of ships [1][2][3], as well as in other advanced industries such as automotive, defense, and aerospace [4][5][6]. This is due to aluminum's outstanding mechanical properties, such as its high strength-to-weight ratio, low density, high resistance to corrosion, easy fabrication, and recycling [7,8].…”