Blast impact on structures of underground parking

Abstract

In big cities underground spaces are built up for subways, underground parking and tunnels, etc. These rooms are threatened by terrorist attacks and not only human lives can be lost but also extensive material damage can be expected. This is why it is of great importance to predict dynamic impacts of explosives, which can then be transformed to static statistically evaluated loading. In this paper the impact of explosion and air strike wave is formulated and solved. Gas dynamics and dynamic response of soil with process of dissipation of air-strike energy are considered. This means that some part of this energy is transferred into structures and soil mass. It appears that for contact explosions on the soil surface this part can be up to 30% of the total explosion energy (in soft soils). The variables to be calculated are mass density of gas, the velocity of movements and the internal energy. The latter covers the influence of the gas pressure, being given for the adiabatic state. The air is linearly related to the internal energy of a unit mass of the gas, and the density, while in the neighborhood of the source of explosion the pressure changes nonlinearly with respect to the gas density. Time dependent finite element solution is compared with results published in Lucy, L.B. (1977). A numerical approach to testing of the fission hypothesis. Astron. J. 82, 1013.

Smoothed Particle Hydrodynamics (SPH): an Overview and Recent Developments

“…Traditional Eulerian techniques, such as the finite difference methods or finite volume methods, can well resolve the problem due to the large deformations in the global motions, but it is very difficult to analyze the details of the flow because of the lack of history and the smearing of information as the mass moves through the fixed-in-space Eulerian mesh [256]. Considering the difficulties of grid based numerical models, the meshfree particle methods can be a good alternate for simulating detonation, explosion and underwater explosions [125,136,143,247,248,252,255,256,[345][346][347][348][349][350].…”

“…Therefore different shapes and sizes of the SPH particles increase the difficulty in implementing the contact algorithm. During the course of SPH development, different contact algorithms have emerged [126][127][128][129][130][131][132][133][134][135][136][137][138][139][140][141][142]. For simplicity, only SPH models with circular or spherical shaped particles are discussed here.…”

Modeling the Impact of Explosions in Enclosed Spaces Using Discontinuous Boundary Elements and Finite Volume Methods

“…Interaction of pressure due to the shock wave and an arch shell is found in [9]. The effect of explosion in underground spaces was also published in WIT conferences; see [10], [11].…”

“…Since the number of degrees of freedom may be very extensive, for calculation of accelerations at time T the forces t i F and moments t M are utilized. It means that (7) is applied in the sense of the mentioned assumption: (10) and the new velocities of the particles…”