Protective Performance of Hybrid Metal Foams as MMOD Shields

Abstract

Open cell aluminum foam core sandwich panel structures have been proven to be of interest for protecting satellites against micrometeoroids and orbital debris (MMOD). Bumpers containing aluminum foam show outstanding capabilities to induce multiple shocks to small projectiles in the hypervelocity regime. For this work the protective performance of foam cored sandwich panels with cores made from newly developed hybrid metal foams was evaluated. Therefore shots in the hypervelocity regime on the two-stage light gas gun of the French-German Research Institute of Saint-Louis were performed. The tested targets were sandwich panels with aluminum front and rear facesheets and cores of different types of metallic foams: foams with pore densities of 10 pores per inch and 45 pores per inch were tested as pure aluminum and hybrid metallic foams. The projectiles to simulate micrometeoroids and orbital debris were aluminum spheres with a diameter of 4mm. The impact velocity was 6500m/s. It could be shown experimentally that the nickel coating of the aluminum foams leads to a decreased crater depth in the sandwich panels. However, scatter in the coating thickness leads to variations in the foam densities of the hybrid foams, making the evaluation of the increase in the protective performance difficult. Nevertheless, due to the nickel coating the influence of the pore density seems to be more significant than reported before. By reducing the coating thickness and using high performance aluminum alloys as base material for the hybrid foams, further optimization of the protective performance could be reached. Then, the complete evaluation of the ballistic limit over a broad velocity regime should be done to see the variations in the performance of the hybrid foams over the whole velocity range being of interest for MMOD shielding technologies

Investigation of Strain‐Rate Effects in Ni/PU Hybrid Foams under Low‐Impact Velocities

“…They are used in crumble zones for cars, trains, and in the packaging industry. Further potential applications for military and civil structures in terms of protection against ballistic impacts found in the literature are space debris shields, claddings, armor systems, and helmets …”

Experimental and Numerical Study of Ballistic Resistance of Composites Based on Sandwich Metallic Foams

“…Klavzar et al considered the possibility of using a core of nickel (Ni)-coated aluminium foam with open porosity (PPI 45, 30, 10) in ballistic shields. The addition of Ni provided a reduction of the deformation zone after shooting in relation to the reference samples without coating [16]. As the thickness of the nickel layer increased, an increase in the stiffness and strength of the foam was observed.…”

“…Fig 16. View of the core of the projectile after passing through the material, in the numerical simulation…”

Synthesis and Mechanical Properties of Novel Ni/PU Hybrid Foams: A New Economic Composite Material for Energy Absorbers

“…Microscopically, the PCS is the collapsing stress of the first pore layer in the foam. [12][13][14][15][16][17][18] Specific values are needed for the comparison, since the coating increases the foam density. In closed cell foams, other processes like pressure build up in the closed cells will occur as well and influence the microdeformation mechanism.…”

“…These Ni/Al hybrid foams show a significantly improved reproducibility, specific strength, and specific energy absorption capacity per density. [12][13][14][15][16][17][18] Specific values are needed for the comparison, since the coating increases the foam density.…”