The paper presents unique blast experiments in reference to scientific literature and official standards. Experimental scenarios reflect a hypothetical realistic combat situation of a human being covered from a blast wave behind a rigid building corner. In the scenario assumed, the overpressure loads affect the lungs while the person is standing or the eardrums while the person is kneeling at the aiming position. The paper presents 27 free-field experiments measuring the overpressure loads. All the measurements were taken behind the right angle of the rigid wall. Two masses of TNT were considered: 200 g and 400 g. In the selected cases, a low test-to-test variability of the measured data was observed. Detailed plots of overpressure versus time are presented for various distances behind the building corner and TNT charge masses. Peak overpressure versus positive impulse plots are also demonstrated. Furthermore, the safety thresholds regarding different locations behind the building corner are defined for the considered explosive masses.

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The need for more effective defence systems is of critical importance because of the rising risk of explosive attacks. Sandwich panels are used as plastically deforming sacrificial structures, absorbing blast wave energy. To the authors’ knowledge, the blast behaviour of sandwich panels with connected (welded/bolted/riveted) corrugated layers has been well covered in literature. Hence, the aim of this numerical study was to develop new, easy-to-build, non-expensive, graded sandwich panel with ‘unconnected’ corrugated layers that can be used as a multipurpose sacrificial protective structure against wide range of blast threats. The proposed sandwich panel is composed of six unconnected aluminium (AL6063-T4) core layers encased in a steel (Weldox 460E) frame with 330 × 330 × 150 mm overall dimensions. The numerical analysis was conducted using Abaqus/Explicit solver. First, the performance of four different nongraded layer topologies (trapezoidal, triangular, sinusoidal, and rectangular) was compared, when subjected to ~16 MPa peak reflected over-pressure (M = 0.5 kg of TNT at R = 0.5 m). Results showed that the trapezoidal topology outperformed other topologies, with uniform progressive collapse, lower reaction force, and higher plastic dissipation energy. Then, the trapezoidal topology was further analysed to design a ‘graded’ sandwich panel that can absorb a wide range of blast intensities (~4, 7, 11, 13, and 16 MPa peak reflected over-pressures) by using a (0.4, 0.8, 1.2 mm) stepwise thickness combination for the layers. In conclusion, the superior performance of the proposed sandwich panel with unconnected graded layers can be considered as a novel alternative to the conventional costly laser-welded sandwich panels. Applications of the new solution range from protecting civil structures to military facilities.

In this paper, an experimental investigation is presented for sandwich panels with various core layer materials (polyisocyanurate foam, mineral wool, and expanded polystyrene) when subjected to a justified blast load. The field tests simulated the case for when 5 kg of trinitrotoluene (TNT) is localized outside a building’s facade with a 5150 mm stand-off distance. The size and distance of the blast load from the obstacle can be understood as the case of both accidental action and a real terroristic threat. The sandwich panels have a nominal thickness, with the core layer equal 100 mm and total exterior dimensions of 1180 mm × 3430 mm. Each sandwich panel was connected with two steel columns made of I140 PE section using three self-drilling fasteners per panel width, which is a standard number of fasteners suggested by the producers. The steel columns were attached to massive reinforced concrete blocks via wedge anchors. The conducted tests revealed that the weakest links of a single sandwich panel, subjected to a blast load, were both the fasteners and the strength of the core. Due to the shear failure of the fasteners, the integrity between the sandwich panel and the main structure is not provided. A comparison between the failure mechanisms for continuous (polyisocyanurate foam and expanded polystyrene) and non-continuous (mineral wool) core layer materials were conducted.

The present study focused on the behaviour of the AW-6060 aluminium alloy in peak temper condition T6 under a wide range of loads: tensile loading, projectile and explosion. The alloy is used as a structural component of civil engineering structures exposed to static or dynamic loads. Therefore, it was crucial to determine the material’s behaviour at low and intermediate rates of deformation. Despite the fact that the evaluation of the strain rate sensitivity of the AW-6060 aluminium alloy has already been discussed in literature, the authors of this paper wished to further investigate this topic. They conducted tensile tests and confirmed the thesis that the AW-6060 T6 aluminium alloy has low strain rate sensitivity at room temperature. In addition, the fracture surfaces subjected to different loading (tensile loading, projectile and explosion) were investigated and compared using a scanning electron microscope, because the authors of this paper were trying to develop a new methodology for predicting how samples had been loaded before failure occurred based on scanning electron microscopy (SEM) micrographs. Projectile and explosion tests were performed mainly for the SEM observation of the fracture surfaces. These tests were unconventional and they represent the originality of this research. It was found that the type of loading had an impact on the fracture surface.