Investigation into the Effects of Blockage and Frangible Tunnel Sections on Blast Pressure Profiles

Abstract:

Atomic Weopons Establishment (AWE) is tasked with substantiating the performance of numerous systems in diverse environments. Often this involves both experimental trials and numerical analysis undertaken in an integrated manner. One area in which this approach has been applied is the assessment of structural response to blast loading. Experimental testing is undertaken using blast tunnels/tubes to generate surrogate environments and obtain appropriate load profiles. AWE’s Air Blast Tunnel (ABT) – a unique facility for generating large-scale long duration blast waves – is commonly employed for this purpose. Modelling activities, including finite element analysis (FEA), hydrocode analysis and engineering calculations, are performed in conjunction with the trials to optimise their output. Data collected during the tests is subsequently exploited to facilitate model validation. Validated models are then used to study the true environments of interest. To complement the ABT and provide a facility in which new and novel test methods and technologies can be explored, the ‘Mini Air Blast Tunnel’ (MABT) was recently designed and constructed by AWE. One of the first applications of this facility was to support exploration of methods to engineer blast profiles and scale to larger tunnels; an area of ongoing interest. 18 shots were fired with various configurations of frangible section and/or tunnel blockage to study their effect on the blast profiles obtained. This study was accompanied by complementary analysis employing coupled Fluid-Structure Interaction (FSI). Pressure data recorded during the experimental trial were used to validate the model prior to it being exploited to consider further configurations that were not tested. The analysis revealed the influence of the thickness and strength of the frangible section on pressure-time histories within it, as well as the impact of blockage on increasing load on the test item in addition to the internal radial load applied to the tunnel structure. An overview of the trial and modelling activities will be provided whilst highlighting key similarities and differences between model and test results. The challenges and limitations encountered in the study and its potential future direction will also be discussed.

• Periodical: Advances in Science and Technology (Volume 171)
• Pages: 25-30
• DOI: https://doi.org/10.4028/p-iX7lhC
• Online since: December 2025
• Authors: Aljo Jose*, Chris Taggart, John Adams
• Keywords: Blast Tunnel, FEA, Fluid Structure Interaction, Hydrocode Modelling

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