Lightweight protective configurations against blast and fragments impact: Experimental and numerical studies

Abstract

Lightweight protective configurations against blast and fragment impacts were studied experimentally and numerically. The configurations comprised different combinations of Kevlar fabrics, laminated GFRP (Glass Fiber Reinforced Polyester), polyurethane (PU) foam, and alumina (Al2O3). The polyurethane (PU)–sand multi-layer composition and a mixture of polyurethane–sand and polyurethane–alumina powder were also studied. The protective configurations were tested under static detonation of a scaled down artillery shell. Protective capabilities were tested against a peak incident overpressure of 57 psi and fragments weighing up to 4.3 g carrying velocities in the range of 961 m/s–1555 m/s. Numerical simulations were performed using ANSYS AUTODYN. The coupled SPH (Smoothed Particle Hydrodynamics)–ALE (Arbitrary Lagrangian–Eulerian) approach was used to simulate the interaction of fragments with protective configurations. A coupled Euler–ALE approach was employed for blast wave loading on protective configurations. The Kevlar fabrics, laminated GFRP, and PU foam compositions provided significant absorption and attenuation to impacting fragments. Configurations employing alumina tile were able to withstand both blast and fragment impacts without significant backface signatures (blunt force trauma). The configurations can be employed as body armor, vehicle armor, and for the safety and security of other critical infrastructures against blast wave and high velocity fragment impact. Numerical simulation results are in fair agreement with experimental results.

Blast and Fragmentation Studies of a Scaled Down Artillery Shell-Simulation and Experimental Approaches

“…As the computational grid influences the accuracy and reliability of the numerical prediction results [30]. A particle size of 1 is used for packing after optimizing the size for SPH solver [2,23]. Quarter symmetry of the shell is modeled with 28820 nodal points to reduce the computational time.…”

“…The interaction between the two solvers is controlled by an automatic coupling option available in ANSYS AUTODYN. An optimized grid size of 1x1 mm 2 is used for both solvers [2,23]. The air surrounding the shell is filled for ambient pressure of 101kPa (14.7psi) by assigning specific internal energy of 2.068e+5 kJ/kg.…”

“…The neighboring objects are first hit by this blast wave followed by the high velocity fragments causing severe damage. The study of the fragmentation phenomenon is important for design, safety and efficiency analysis of ammunition, as well as to devise protective measures against the damaging effects [1,2]. The fragment velocity, shape and mass distribution support in completing the characterization of the fragmentation process [1].…”

Experimental investigations of the response of a portable container to blast, fragmentation, and thermal effects of energetic materials detonation

“…Various configurations were placed at radial distances of 0.55–0.80 m from shell. The configuration, shown in Figure 7, was tested twice against the static detonation of scaled down shell and has shown significant resistance to close in blast loading and high velocity fragments penetration and perforation (Ahmed et al, 2020). A total of 26 fragments impacted the configuration and only 8 were able to perforate in both tests.…”

“…In present study a novel combination of composite materials was employed at the base of the container including Bakelite, PU-silica, and extended Polystyrene (EPS) foam having thickness 12, 27, and 43 mm respectively. The PU-silica composite shown in Figure 8(a) was prepared in multiple layered formulations with composition 85% PU and 15% silica has shown good thermal resistance and shock absorbance at extreme conditions (Ahmed et al, 2020). The PU-silica composite has density of 1100 kg/m 3 and compressive strength of 232 MPa at 10% strain and has shown ductile behavior and good toughness during the compressive strength test.…”