The purpose of this study is to investigate the effect of BLAST WAVE TRAP on reducing the detonation effect in tunnels and its effect on reducing the load on the explosion-proof door end of the tunnels and to analyze the types of doors in order to determine which type has the best performance against detonation. To this end, the propagation of the WAVEs induced by the explosion of TNT-type beams with different weights is simulated in the tunnel span with a BLAST WAVE TRAP. The AUTODYN hydrocode is used for numerical simulations. The simulation and numerical modeling are compared and validated with analytical and empirical relationships of previous studies. Considering the maximum pressure applied to the tunnel intersection, the proper location of the BLAST WAVE TRAP, the optimal BLAST WAVE TRAP length and its effect on the maximum value of the tunnel end pressure are investigated. The output of the load applied to the end of the tunnel (location of the explosion-proof door) resulting from this time-dependent explosive load modeling is transferred to ABAQUS software to analyze and compare the types of explosion-proof doors. From the point of the load exerted on explosion-proof doors, hinged doors with different flat and arched geometries are analyzed using ABAQUS software and the maximum displacement and von-Mises stress of the doors are compared. The results show that the arch door performs better than the flat door.

BLAST WAVE TRAP is one of the ways to deal with and reduce the effects of BLAST WAVE inside the secure underground structures. In this paper, the effect of BLAST WAVE TRAP on reducing the overpressure in the main route of the tunnel has been studied. Accordingly, the BLAST WAVE propagation of different explosives in various distances from the tunnel entrance including BLAST WAVE TRAP has been simulated. Autodyn software was employed for numerical simulation.Based on the ratio of the overpressure applied to BLAST WAVE TRAP to obtained overpressure of the main route after BLAST WAVE TRAP, the appropriate distance and optimum length of the BLAST WAVE TRAP were calculated. The results show that BLAST WAVE TRAP can significantly reduce the overpressure applied to the BLAST WAVE TRAP zone. Besides, higher values of overpressure before BLAST WAVE TRAP zone leads to an increase of optimum length of BLAST WAVE TRAP along with more pressure reduction.

BLAST WAVE interaction with objects has gained attention due to military conflict and terrorist attack across the globe. BLAST WAVE attenuating and mitigating structures are needed to be developed to protect the military vehicles and commercial buildings. In order to understand the attenuating mechanism such as the dissipation and dispersion along with the secondary effects, the BLAST WAVE interacting with three objects is examined in the present study for the diaphragm pressure ratio of 56. Here, the BLAST WAVE is generated in a short driver section open ended shock tube by solving the Euler equations using the commercial software ANSYS Fluent. It has been observed that the circular disc attenuates the BLAST WAVE more effectively compared to the cone and sphere for the same frontal area. The attenuation was lowest in the sphere and maximum in the circular disc. However, the loads acting on the sphere was more compared to the conical object. The peak load acting on the circular disc was 2. 09 times more compared to the peak load acting on the conical object (cone angle 26. 5° ) with the same hydraulic diameter.

Most existing structures are vulnerable to the BLAST WAVE loads and therefore their resistance to such loads should be evaluated. In this study, the behavior of RC slabs under BLAST loading was investigated numerically. Numerical analysis can reduce the number of required expensive experimental BLAST tests. The variable parameters for study include: thickness, reinforcement ratio and spacing, support conditions, dimensions of slabs and location and amount of explosives. Numerical modeling was performed by the use of LS-DYNA software. It is capable of modeling the explosion and also has a wide range of material models.The results showed that the slabs were completely destructed under near explosion mainly because of punching shear. Under medium distance explosion, no complete destruction was observed. The deflection and the extent of cracking depended on the thickness and reinforcement ratio and somewhat on reinforcement spacing. The slab thickness and support condition had also a significant impact on the behavior of slabs. Interestingly, the cracking level of RC slabs did not change significantly by increasing span length.

In the current research the maximum deflection of circular plates made of the AA5010 and AA1100 alloys under BLAST load was investigated. Shock WAVEs were produced by exploding a spherical charge in different distances from the center of plates. The ABAQUS software uses the conwep equation for the BLAST loading analysis. It was found that the results of these simulations have about 30% to 40% inaccuracy in comparison with experimental results. To improve the accuracy of simulations, the Friedlander equation was used that considers the positive phase of BLAST WAVE as exponential and the negative phase as bi-linear function. To this goal, the VDLOAD subroutine was developed. Results were shown the difference between the experimental and simulation data was decreased to 8%. Moreover, the effect of uniform and non-uniform shock WAVEs on deformation of structure and various failures were investigated. It was observed that uniform shock WAVEs can be attained when the minimum distance of exploding charge and plate is about 3 times of the radius of plate.

One of the intrinsic properties of foams, porous materials, and granular materials, are their ability to mitigate the BLAST WAVE. The current research study investigates the capability of granular materials in the mitigation of BLAST WAVE both experimentally and numerically. In the experimental section, the explosion shock tube facility was employed to conduct a series of experiments. Sawdust and mineral pumice were used as granular materials in the sandwich panel core and their mechanical properties were obtained by performing quasi-static compression tests. Moreover, the commercial hydrocode AUTODYN was used to numerically simulate the process while the smooth particle hydrodynamics method (SPH) was employed to model granular materials. The obtained results indicate that mineral pumice leads to more mitigation of the BLAST WAVE compared to sawdust. Besides, using a low thick core made of granular materials is not considerably effective and using a high thick core leads to more mitigation of the BLAST WAVE.

Behavior of BLAST WAVE in underwater explosion is of interest to metal forming community and ship designers. Underwater detonation is, also a potential hazard to the water intakes or a plant spent fuel pool. In this paper, some techniques for calculating free-field BLAST parameters such as pressure and impulse in underwater explosion and prediction of bubble pulsation parameters are presented and they will be compared by experimental results of underwater detonation of Hexogen explosive charge. The details of pressure pulse curves generated by detonation of Hexogen in several standoff distances are obtained, that by using scaling laws, they can be used in analysis of practical underwater detonations. Finally, the equivalent mass of Hexogen charge relative to TNT in underwater explosion is calculated.

BLAST WAVE propagation in a granite rock mass and its interaction with existing discontinuities are simulated and studied by means of UDEC software. For this purpose, a BLAST shock WAVE is simplified as a triangular pulse, with the specific maximum pressure of 16.5 GPa and time duration of 0.01 to 0.08msec, which was placed in a 200 mm diameter BLAST hole. Results of the numerical analysis along the discontinuity are compared with both field results and the Dowding empirical formulae. A relatively good correlation is observed between numerical analysis results and field data.

The purpose of this study is to investigate the vulnerability of Shiekh Bahaei’, s bath under the BLAST WAVE. This study was performed as a numerical study using software analysis. The method of three-dimensional nonlinear finite element analysis was selected by Abaqus software. Nonlinear dynamic analysis method was selected to determine the moment-to-moment response of the structure to the explosive load. The Drucker Prager criterion is also used to model building materials in Abaqus software. The accuracy of finite element modeling results was ensured by comparing the modeling results with the laboratory sample. The finite element model of Shiekh Bahaei’, s bath was modeled in Abaqus software and nonlinear dynamic analyses under the BLAST WAVE were performed. Then, the results were compared in the form of tensile damage meters and displacement-time diagrams. Based on the results of this study, the location of the breakdown and the amount of displacements in different parts of the bath under the BLAST WAVE were determined.

In this research, the interaction of BLAST-induced stress WAVEs with the surrounding sedimentary media containing bedding planes was investigated by the UDEC code. The stress WAVE resulting from the detonation of a cylindrical hole was simulated by a triangular pulse, which is the result of an overpressure equivalent of 1635 MPa. This pressure was applied to the BLAST hole wall as a uniform load. The reflection and transition coefficients of two media (sandstone and limestone) at both sides of the bedding plane were estimated for both elastic and plastic media behavior. The obtained numerical results were compared against analytical solutions. A good agreement between numerical and empirical results was achieved.