Aqueous foam provides a dispersion of the gaseous phase in the liquid phase. The commercially available aqueous foam (Denim shaving foam-original) has been investigated for its stability and capability for reducing the extreme thermal and blast effects associated with an energetic material detonation. The dry aqueous foam has evenly distributed bubbles with an average initial size of 15 µm. Different amounts of the C4 explosive were detonated while immersed in the dry aqueous foam having a density 60 kg/m3. The blast wave parameters were measured in the field for scaled distances ranging from 0.39 m/kg1/3 to 1.80 m/kg1/3 based on the cube root law. The dry aqueous foam confinement suppressed the explosion fireball radius up to 80% and quenched the afterburning reactions. An average peak pressure reduction of 70% and positive impulse reduction of ∼62% were observed for hemi-spherical confinement of the dry aqueous foam weighing 1.0 kg–2.75 kg against C4 charges of 82 g–250 g. The shock propagation is attenuated due to the high compressibility of gas bubbles. The dry aqueous foam may be used in emergency circumstances such as against energetic material detonation and lighter improvised explosive device threats to reduce the devastating blast effects. The numerical simulation results using ANSYS AUTODYN for bare charges are in fair agreement with the experimental findings.

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.

Configuration of a heterogeneous lightweight material is investigated numerically and experimentally, for protection against 7.62 × 39 mm mild steel core bullet impact. The configuration consists of alumina (Al2O3) tile followed by fiber glass and polyurethane foam, all covered with kev-epoxy layer. Numerical simulations were performed using ANSYS AUTODYN. The 10-mm thick alumina completely disrupts the impacting bullet through blunting and erosion. The fiber glass and polyurethane foam disperse and absorb the propagation of shock wave, respectively. The kev-epoxy cladding seizes any scattering of brittle alumina fragments. The average impact velocity of the bullet was measured to be 710 m/s using high-speed camera. A 10-mm depth of depression spread over a wider area of 3.92 sq in of torso was recorded in blunt force trauma test, which was well within the European, German, and British standards that allow a 20–25 mm backface signature. Due to these characteristics it can be employed as body armor, vehicle armor, and for the safety and security of other critical infrastructures against this bullet and fragment impact. The residual mushroom-shaped bullet and its length of 9.3 mm in numerical simulation is in close agreement with the measured value of the 8.0 mm recovered bullet size and shape.

Blast and fragmentation of a scaled down model of standard artillery shell is investigated experimentally and numerically. Simple experimental techniques are employed in this study to measure the fragments' velocity, mass and spatial distribution. Fragments of mass ranging from tens of milligram(s) to 6.4 grams are produced with velocities ranging from 960 to 1555 m/s. The cylindrical part of the shell has larger contribution among high velocity fragments ~1369-1555m/s than the conical and rear parts due to higher charge to mass (C/M) ratio. Overpressure of 44.2psi (304.7kPa) is measured at stand-off distance of 0.550m. The numerical simulation of fragmentation is carried out using Smoothed Particle Hydrodynamics (SPH) solver available in ANSYS AUTODYN. A coupled Euler-ALE (Arbitrary Lagrangian-Eulerian) approach is used to simulate the shell blast propagation in the surrounding air. A good agreement is achieved between the simulation and experimental results. The investigation can help in the development of protective configurations against the damaging effects of blast and fragmentation.

The detonation of an energetic material (EM) is manifested in the form of blast wave, fragmentation of casing material, and thermal effects. These effects are very destructive and cause injuries-being fatal-and structural damage as well. The attenuation of these effects is a prime focus. C4 explosive weighing 104 g was tested as surface burst. Peak overpressures of 1362 kPa and fireball radius of 0.65 m were measured. A multi-layer container comprised steel liner, Kevlar woven fabric, and laminated glass fiber reinforced polymer (GFRP) was developed and investigated to counter the combined blast, fragmentation, and thermal effects of EM detonation. Commercially available shaving foam was characterized and used as filling material inside the container. The foam bubbles have shown a good stability with time. The shaving foam quenched the fireball and afterburning reactions owing to rapid heat and momentum transfer mechanism. The containment system provided more than 80% overpressure reduction with respect to an equivalent open-air detonation and also restricted any escape to lateral directions. Coupled Euler-ALE (Arbitrary Lagrangian-Eulerian) approach was employed to numerically simulate the blast wave parameters. A good agreement is obtained between the simulation and experimental results.