Study on the failure effect of aramid reinforced concrete slab under localized blast loading

As a new material with low density, high modulus and high strength, aramid fibers and composite laminates are widely used in protective structures. Aramid reinforced concrete panels as a new type of protective combination of structures, especially in the concrete-aramid laminate composite blast-resistant structure, the optimal thickness combination of reinforced concrete and aramid laminate has not been targeted research. In this paper, three types of scaled down reinforced concrete (RC) slabs, aramid fiber reinforced concrete (AFRC) slabs and aramid fiber reinforced plastic reinforced concrete (AFRPRC) slabs were designed and fabricated to carry out experimental studies under local explosive loading and to compare the blast resistance of different slabs through damage analysis. Based on LS-DYNA software, the damage characteristics of AFRPRC plates were investigated and compared and analysed with the test results to verify the accuracy and applicability of the FEA model. Typical damage patterns of structures under different TNT charges were obtained, and empirical equations between the damage characteristics of reinforced concrete slabs (maximum mid-span displacement, crater diameter, crater depth) and TNT charges were fitted by means of magnitude analysis. The effect of the aramid layer on the structural blast resistance performance was analysed from three perspectives: maximum central displacement, stress wave attenuation rate and internal energy absorption. The results show that AFRC improves the blast resistance of reinforced concrete not significantly relative to ordinary reinforced concrete slabs, while AFRPRC slabs maintain good integrity and show better blast resistance. The best blast resistance performance of AFRPRC panels is achieved when the ratio of reinforced concrete thickness to aramid layer thickness is 50:3. The results of the study can provide theoretical basis and reference for efficient protection of composite structures.