# Blast resistance of re-entrant auxetic cored sandwich panels with tunable stiffness

## TL;DR

This study introduces a new sandwich panel design with tunable stiffness that improves blast resistance and energy absorption compared to traditional designs.

## Contribution

A variable stiffness re-entrant core is proposed for enhanced blast protection with adjustable energy absorption.

## Key findings

- VSRE core reduces lower plate displacement by 11.85% compared to traditional cores.
- Energy absorption increases by 14.39% with the VSRE design.
- Combining VSRE with a thicker rear plate reduces peak deformation by up to 81.11%.

## Abstract

As the threat of explosion incidents continues to intensify, it poses a significant risk to human safety. This study proposes a variable stiffness re-entrant (VSRE) core sandwich panels with negative Poisson’s ratio to enhance the explosion protection effect. Numerical simulation methods are used to analyze the impact of explosion loads on the structure, and the model is verified using the experimental results from existing studies. The VSRE core demonstrates excellent explosion protection performance. Compared with the traditional re-entrant (RE) core of equivalent mass, in the numerical simulation, the lower plate maximum displacement (maxD) is reduced by 11.85%, while the energy absorption (EA) of the system is increased by 14.39%. The variable stiffness factor of this design enables the control of density deformation, thereby achieving adjustable energy absorption capacity. The parameter study of the system shows that through the reasonable combination of core thickness, side distance, and gradient configuration, the best performance can be achieved. Specifically, combining the VSRE core with a thicker rear plate can more effectively distribute stress and material flow, reducing the peak deformation by up to 81.11%. This structure enables more efficient material flow towards the deformation center, effectively reducing the overall deformation and improving the energy absorption capacity. Therefore, the application of this variable stiffness helical plate in explosion protection systems has great potential.