Different approaches of numerical simulation of blast Ing. Matúš Ivančo Ing. Lucia Figuli, PhD.

Content Analytical methods SDOF, MDOF Numerical method CFD, TNO Multi-Energy method, FEM Solvers Commercial software

Analytical methods A single degree of freedom (SDOF) system requires only one coordinate to describe its position at any instant of time (springmass-damper system). A multi degrees of freedom (MDOF) system is a system that requires two or more coordinates to describe its motion.

Numerical simulation CFD (Computational fluid dynamics) TNO Multi-Energy method FEM (Finite Element Method) Implicit FEM Explicit FEM

CFD (Computational fluid dynamics) Advantages: more accurate energy estimates and resulting blast wave pressure, ability to evaluate unbalanced effects caused by realistic geometries, gas cloud changes and ignition sites.

TNO Multi-Energy method The procedure for the determination of the explosion force with TNO MEM is as follows: Determine an obstacle and / or an unrestricted region. Determine the class number and estimate the strength of sources in each region. Determination of the gas cloud radius. Calculation of scaled distance, positive pressure phase and duration (explosion parameters). Calculation of positive overpressure, duration and positive impulse (actual parameters).

Ingnition energy Obstacle density Confinement Strenght Low High No Existing X 7 – 10 5 – 7 4 – 6 4 – 5 3 – 5 2 – 3 1 – 2 1

Types of flame expansion TNOMEM charge strenght Mixture reactivity TNOMEM charge strenght Obstacle density High Medium Low 1-D 10 9 – 10  9  7 – 8 7 – 8 6 2-D 9 4 – 5 6 – 7 2 – 3  5 – 6  1 – 2 3-D 3 1 3 – 4  2  1

FEM (Finite Element Method) The finite element method is a calculation method that divides the CAD model into very small but ultimately geometrically simple geometric shapes. The collection of all these simple shapes forms the so-called finite element network. Finite Element Method can by devided into: Implicit FEM Explicit FEM

Solvers Lagrangian Eulerian

Apollo Blast Simulator Commercial Software Software Implicit Method Explicit Method Discretisation Lagrangian Eulerian Lagrangian/Eulerian ABAQUS X ANSYS   LS-DYNA AUTODYN MSC.DYTRAN NASTRAN EUROPLEXUS ASTER SOPHIA ProSAir Apollo Blast Simulator

ABAQUS Abaqus is a software suite for finite element analysis and computer-aided engineering. The Abaqus product suite consists of five core software products: Abaqus/CAE,(Complete Abaqus Environment), Abaqus/Standard, Abaqus/Explicit, Abaqus/CFD(Computational Fluid Dynamics), Abaqus/Electromagnetic. Used for both the modeling and analysis of mechanical components and assemblies and visualizing the finite element analysis result. A general-purpose Finite-Element analyzer that employs implicit integration scheme. A special-purpose Finite-Element analyzer that employs explicit integration scheme to solve highly nonlinear systems with many complex contacts under transient loads. Software application which provides advanced computational fluid dynamics capabilities with extensive support for preprocessing and postprocessing provided in Abaqus/CAE. Software application which solves advanced computational electromagnetic problems.

ABAQUS

ABAQUS

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