Ballistic resistance analysis of hard ceramic combined with aluminum foam sandwich constructions

A ballistic resistance of hard ceramic combined with aluminum foam sandwich (CAFS) constructions was investigated in this paper. This combination plate is constructed by a front faceplate (FFP), ceramic plates, an aluminum foam (Al-foam) panel, and a rear faceplate (RFP). The material used for the FFP and RFP was heat-treated mild steel with the thicknesses are 5 mm and 3.5 mm, respectively. The ceramic materials to be evaluated are B4C, SiC, and Al2O3. Al-foams were fabricated by varying the stabilizer weight ratio of MgO and Al2O3. The Al-foams have a porosity of 79.93%–82.57%, a pore diameter of 2.51–2.82 mm, the relative density of 0.17–0.24, and plateau stress of 3.88–6.63 MPa. Ballistic tests were carried out only for aluminum foam sandwich (AFS) construction without ceramics to evaluate the manufacturing effect and to obtain a baseline ballistic plate to be improved. Ballistic tests are conducted by using 5.56 × 45 mm bullet with 50 m shooting range and bullet speed of 929–958 m/s. To validate the damage mode and energy absorption capability of the AFS, a numerical model is constructed. The numerical studies were conducted to investigate the damage mode and energy absorption capabilities of each part. The simulation has a good agreement with the experiment result on the damage mode. This model then to be used to study the effect of the additional hard ceramic layer. An interaction between hard ceramic and AFS is also investigated to get a new insight of the energy absorption mechanism during bullet penetration. A new finding shows that ceramic presses the Al-foam to solidify so that it can increase the energy absorbed by the Al-foam. The ceramic is impacted by a bullet pushing the Al-foam so that it undergoes solidification which leads to increasing absorbed energy.