PSI - Issue 60

Prince Jeya Lal Lazar et al. / Procedia Structural Integrity 60 (2024) 185–194 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

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sandwich honeycomb panels plays a significant role in the structural response to a surface explosion, especially when the stand-off distance and explosive charge mass are kept constant. Thicker honeycomb cores typically provide better protection against front-face deformation in response to a surface explosion. A thicker core has more material to absorb and dissipate the energy generated by the blast wave, which reduces the impact on the front face. As the core thickness increases, the panel becomes more resistant to bending, deflection, and damage. This helps in maintaining the panel's shape and structural integrity. When the explosion occurs, the core material acts as a sacrificial buffer, absorbing the energy from the blast. A thicker core of high mass can absorb more energy before reaching the point of core crushing. Core crushing can be especially detrimental because it can lead to a loss of structural integrity and result in the failure of the panel. It was witnessed that, an increment of core thickness from 0.76 mm to 1 mm, and 1.5 mm (an increment of 31.57% and 97.36%) reduced the front face midpoint deflection by 7.91% and 36.84%. With an increase in core thickness, a reduction in face-sheet stress, and a delay in core crushing is observed. However, a thinner core resulted in higher levels of stress and an earlier core failure. Different core configurations may exhibit different optimum core thicknesses for varying blast load cases. Hence, from a designer's standpoint, the selection of the optimum core thickness for sandwich panels depends on various factors, such as the base material properties, constraints in the overall mass of the panel, face-sheet thickness, unit cell configuration, and impulse load.

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Fig. 7 Front face midpoint deflections in panels exposed to a blast load equivalent to 1 kg TNT at a standoff distance of 100 mm for the varying core thickness of (a) 0.76 mm (b) 1 mm (c) 1.5 mm [a, b, c – Surface explosion & d, e, f – Underwater explosion]