• Comparison of numerical methods for modeling the effect of explosion on protective structures

    Trans Motauto World, Vol. 4 (2019), Issue 1, pg(s) 20-23

    Comparison of numerical methods for modeling the impact of an explosion on a metal plate such as LOAD_BLAST; LOAD_BLAST_ENHANCED; Arbitrary Lagrangian-Eulerian; Particle Blast Method; Smooth Particle Hydrodynamics which are implemented in the program LS-DYNA. The adequacy and accuracy of these methods are evaluated depending on the distance ratio to the explosive charge. The advantages and disadvantages of each method and recommendations for their use based on the results of this modeling and the experience of the authors of thisarticleare presented..

  • Material model parameters identification of blast environment

    Security & Future, Vol. 2 (2018), Issue 3, pg(s) 142-145

    In terms of designing or building new protective and security structures or equipment as a physical component of force protection, experimental verification of analytical or numerical calculations and vice versa becomes necessary. While the experiment can be performed on individual components, complex assessment of more complex variants or performing a parametric study is becoming more and more relevant in modelling and simulation domain. For this reason, there is a clear necessity to find the right connection between numerical simulation and experiment.
    Fast, nonlinear processes require nonlinear material models to capture the rate of deformation and material behaviour under extreme loads such as the effect of explosions or the impact of a projectile, i.e. the effects, which the theories and practices of protection of the population and troops are trying to minimize. The important part of the accuracy of computational models is the correct identification of the parameters of material models used in the simulations.
    This paper deals with the simulation of explosion and its effects and identification and optimization of material parameters of the environment in which the explosion and the shockwave propagates, with a focus on the soil material model. The inverse identification method is based on a combination of the experimental measurement data and the computational methods implemented in the finite element solvers and optimization programs. The simulation proceed from experimental measurement curves of blast effects. For measured parameter in the air overpressure at specific measuring points was chosen, while ground-propagating shock wave was evaluated by measuring
    acceleration values. The numerical simulation took place in the LS-Dyna software environment interconnected with the Optislang optimization program.



    Industry 4.0, Vol. 3 (2018), Issue 3, pg(s) 126-129

    Since safe transportation is one of the biggest concerns of vehicle manufactures, occupant safety in vehicle accidents becomes a great challenge.
    The severity of the crash reflects the energy absorption of the car’s structure during the accident and also has a close relationship with the amount of energy absorbed by the restraint system. Among components involved in restraint system, airbags are the most complex ones. The simulation and modelling of this system due to the nonlinear behaviour of the passenger and the vehicle add more complexity to its design and fabrication. Airbag system, which is a subsystem of the restraint system, is very important due to the nature of its multi-physical problem and the direct connection with passenger safety.
    Therefore, in this paper, different approaches to develop airbag dynamics equations has been reviewed. Further a fast design and simulation method for airbag parameters in the concept design phase by an impact problem has been investigated to contribute to a comprehension of the relation between occupants and airbags.