Abstract
The research was based on data obtained from experimental studies and aims in the challenge of mapping these results by a mathematical (phenomenological) model. The field experiments were performed on an H-section steel column supported by a reinforced concrete foundation and subjected to a close-in explosion. Numerical studies were carried out using Abaqus/Explicit code. The user subroutine VUMAT for metallic obstacle was also implemented, together with a coupled Eulerian–Lagrangian approach. The steel column failure recorded during real field tests versus computational results was examined and compared. It was crucial that, from the computational point of view, the obstacle reflected the generalized thermo-elasto-viscoplastic (GTEV) behavior of Perzyna’s type, including an anisotropic measure of damage.
Highlights
Today, the threat of the incidental events, especially in the civil engineering structures, is relatively high
After the ignition moment in the centre of the explosive, the combustion wave goes through the charge domain, and releases a high amount of kinetic and thermal energies; the transition phase generates a high pressure wave on the charge and ambient boundaries; and the pressure reaches the obstacle boundaries and induces the thermomechanical process within its bounds, which is of strong wave character
Equivalent plastic strains are locally as high as ca. 200% in the strain localization zones, the temperature in the strain localization zones is as high as ca. 800 ◦ C, the evolution of the porosity is restricted to the zones of high plastic strains, thermal stresses can be locally as high as 2000 MPa or more, the displacement field is localised in the zone of the evolving flying fragment, whereas in the remaining part for t = 0.7 ms reaches ca. 0.23 m, the strain hardening causes the Huber–Mises–Hencky stresses to be as high as ca. 900 MPa, and air pressure is highly scattered in the fluid domain and reaches locally 150 MPa (161 MPa according to the standards cf. [20])
Summary
The threat of the incidental events, especially in the civil engineering structures, is relatively high. Their research considers a numerical material model of a steel column, in LS-DYNA, that includes plasticity and strain-rate effect. The peak transient and the residual deflections were compared for a clamped circular armor steel plate subjected to large close-range spherical air-blast loading They presented the experimental results from a series of controlled explosions and finite elements calculations. They investigated the effect of impact velocity, impactor mass, impact location, and pre-loading condition on the localization behavior of the steel columns They compared the results with the Johnson–Cook (JC) phenomenological model, implemented in Abaqus. Another comprehensive study on the H-section steel column was done by Hadianfard et al [11] They used a default LS-DYNA material model suited to describe isotropic and kinematic hardening plasticity with the potential of inclusion of strain-rate effects. The second part deals with validation based on the real field outcomes
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