Dynamic behaviors of engineering-scaled laser-welded pyramid lattice sandwich panels under close-in explosions

Pyramid lattice sandwich panels (PLSPs) could meet the requirements of lightweight and high resistance, which has significant advantages in defense engineering. This study aims to propose a practical method to manufacture large-scaled PLSPs through laser cutting and welding with dimension over 1.0 m. Stainless steel 2205 with yielding strength of 640 MPa was chosen as the base material to resist strong explosion impacts. The dynamic responses against explosion of PLSPs were investigated via experimental tests and numerical analyses. For PLSPs in this study, the critical scaled distance is 1.254 m/kg^1/3. With the scaled distance decreasing, progressively buckling of the core occurs, followed by compaction, leading to large deformation of PLSPs. Finite element model (FEM) with damping was established, whose maximum displacement prediction error is less than 20 %. The energy dissipated by the front face sheet, the lattice core and the back face sheet is close to 20 %, over 50 % and over 30 % of the total energy dissipation, respectively. Compared with solid plate with equal mass, the displacement response of PLSPs shows significant attenuation over 80 % in elastic stage and over 20 % in plastic stage. Meanwhile, PLSPs exhibited smaller deformation compared to other large-scale sandwich panels with close dimensions tested under similar airburst conditions.