Vegard Aune

A shock tube facility to generate blast loading on structures

This study evaluates the performance of a new shock tube facility used to produce blast loading in controlled laboratory environments. The facility was found to generate a planar shock wave over the tube cross section by measuring the pressure distribution on a massive steel plate located at the end of the tube. The properties of the shock wave proved to be a function of driver length and driver pressure, and the positive phase of the measured pressure–time histories was similar to those generated from actual far-field explosive detonations. However, the shock tube is also suited to investigate fluid–structure interaction effects and the behaviour of materials in blast events. This was demonstrated using a three-dimensional digital image correlation technique to measure the deformation field of thin steel plates. Synchronization of the three-dimensional digital image correlation and pressure measurements enabled a thorough investigation of the entire experiment and identification of fluid–structure interaction effects. Finally, one-dimensional numerical simulations were performed to investigate the wave patterns during the experiments.

Description of the elasto-plastic material routine SGDI

The report describes the FORTRAN subroutine SGDI for rate-independent deviatoric plasticity with von Mises yield criterion and isotropic hardening, which corresponds to the VM23 material type in the EUROPLEXUS code (abbreviated as EPX in the following). EPX is a Finite Element code for the numerical simulation of fast transient dynamic events in fluid-structural system, jointly developed by the French Commissariat a l’Energie Atomique et aux Energies Alternatives (CEA Saclay) and by the Joint Research Centre of the European Commission (JRC Ispra). The subroutine I part of the FORTRAN90 module M_MATERIAL_VM23. In order to simplify the description of the routine and of the material model, the parts dealing with Gauss point failure and element erosion have been neglected.

A Shock Tube Used to Study the Dynamic Response of Blast-Loaded Plates

This study aims to a better understanding of the performance of a shock tube used to produce blast loading in controlled laboratory environments. Special focus is placed on the influence of the diaphragm failure process on the blast wave formation in the tube. Experimental observations are supported by numerical simulations in an attempt to obtain more insight into the underlying phenomena. It was found that the diaphragm failure process introduces a multi-dimensional flow field downstream the diaphragms. This is observed as a loss of directional energy in the distant flow field and therefore affects the reflected overpressure on blast-loaded plates located at the rear end of the tube. These findings provide important insight into how such a facility works, especially if the dynamic response of flexible plates is of interest.