Analysis of explosion resistance of the blast wall with negative Poisson’s ratio structure

To improve the explosion resistance of the blast wall, it is proposed to combine the negative Poisson’s ratio structure with ultra-high toughness cementitious composites (UHTCC), Through a combination of the explosion experiment and numerical simulation, the anti-explosive property of negative Poisson’s ratio slabs has been studied, to prove the superiority of the anti-explosive properties of the negative Poisson’s ratio UHTCC slabs. Firstly, a negative Poisson’s ratio structural slab was constructed using concrete 3D printing technology and optimizing the printing path, which verified the constructability of the negative Poisson’s ratio structural slab, and the negative Poisson’s slab was subjected to a contact explosion test. Using LS-DYNA software, a finite element model of fluid-solid coupling was established according to the explosion test conditions, and the finite element model was verified by comparison of the slab damage pattern in the contact explosion test and the simulation. On this basis, the verified finite element model was used to simulate and analyze the effects of different materials (concrete and UHTCC), structures (negative Poisson's ratio structure, positive Poisson’s ratio structure, and solid structure), cell concave angles, and solid layer thickness ratios on the anti-explosive properties of negative Poisson’s structural slabs under contact explosion. By comparing the slab damage patterns and the ability of energy absorption, which was determined by the value of the air overpressure behind the slabs, the design of a negative Poisson’s ratio structure target plate with the best anti-explosive properties was obtained. The results show that: (1) due to the high toughness, the explosion resistance of UHTCC slabs is significantly better than that of concrete slabs. The UHTCC slabs all remained intact, and the concrete target slabs were all penetrated. (2) The negative Poisson’s ratio slab has the best ability to absorb energy among the three kinds of structures, while the solid slab is better at maintaining the structural integrity. (3) When the negative Poisson’s ratio of the cell concave angle is 61°, the structure has optimal explosion resistance, and both smaller and larger angles reduce the explosion resistance of the structure. (4) When the thickness of the negative Poisson’s ratio structure is too large as a proportion of the total thickness, the slab is severely damaged. Increasing the solid layer thickness of the backburst surface of the slab, or simultaneously increasing the solid layer thickness of the explosion-facing and backburst surfaces, is conducive to weakening the blast shock wave and improving structural integrity. This study confirmed the superiority of the explosion resistance of negative Poisson’s ratio UHTCC slab, and provides a theoretical basis for the design of blast walls based on negative Poisson’s ratio structure.