Blast response of additive manufactured Ti-6Al-4V sandwich panels

The development of additive manufacturing technique has enabled fabrication of cellular structures with complex architectures and tuned properties, which has revived recent research interests to design and manufacture innovative blast protective structures. This work presents a combining experimental and numerical effort on elucidating the response of additive manufactured (AM) sandwich panels subjected to close-proximity air blast loading. Auxetic honeycomb sandwich panels (AHSP) are fabricated from Ti-6Al-4V alloy via the selective laser melting method. Uniaxial tension tests and metallurgical investigations are, respectively, conducted to reveal the mechanical response and microstructure of the AM alloy. Blast tests are carried out to characterise the deformation and failure behaviours of the blast loaded Ti-6Al-4V sandwich panel. Computational models of the AHSP are built in LS-Dyna and validated with the experiment to provide insights into the dynamic deflection, crack propagation, pressure wave evolution and energy absorption of the AM sandwich panel. Results from parametric studies show that resistance to close-proximity blast loading can be improved with reduced deflection of bottom face sheet for sandwich panel with a low top-to-bottom face sheet thickness ratio or more layers in the auxetic core. This comprehensive study demonstrates the feasibility of using AM sandwich panel with designed auxetic honeycomb cores and face sheets as modern protective structures for enhanced blast resistance.