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Keywords: soil-structure interaction, shock wave, Mach steam, nearby explosion, shaped obstacle.

Summary

The paper presents an investigation on the contact pressure distribution for a shaped buried structure at a short standoff distance from an explosion source and examines the effect of the medium properties on the pressure field and analyzes the structure's response. The analysis is based on a formulation that incorporates the modified coupled Godunov method, a variational difference approach for the soil-structure interaction. The numerical simulations demonstrate that for a short standoff distance and high pressures that are characterized by a steep growth of pressure in the equation of state beyond the full compaction point, a maximum value on the envelope of the pressure distributions along both rigid and flexible shaped (cylindrical) obstacles is located at some distance away from the axis of symmetry. The pressure envelope on the structure in that case has one or two local peaks. The pressure distribution analysis enhances our understanding that this phenomenon is caused by the Mach stem effect appearing in a soil medium with significant hardening. The second peak at the envelope of the pressures appears along a shaped structure only and has not been observed for planar obstacles (buried walls). This phenomenon is caused by the secondary Mach stem effect caused by the structure curvature. It is also demonstrated that the type of peak pressure envelope significantly affects the final shape of the explosive cavity. When the Mach stem phenomenon takes place, the structure affects larger and sharper deformations of the cavity front part, sometimes accompanied with a reverse curvature, thus forming a kidney shape cavity. Otherwise, the cavity maintains its cylindrical shape during the entire process.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 105 PROCEEDINGS OF THE NINTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: Paper 46 The Mach Stem Phenomenon for Shaped Obstacles Buried in Soils Y.S. Karinski¹, V.R. Feldgun¹, E. Racah¹ and D.Z. Yankelevsky^1,2 ¹National Building Research Institute, Technion-Israel Institute of Technology, Haifa, Israel ²Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, Israel doi:10.4203/ccp.105.46 purchase the full-text of this paper Full Bibliographic Reference for this paper Y.S. Karinski, V.R. Feldgun, E. Racah, D.Z. Yankelevsky, "The Mach Stem Phenomenon for Shaped Obstacles Buried in Soils", in , (Editors), "Proceedings of the Ninth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 46, 2014. doi:10.4203/ccp.105.46 Keywords: soil-structure interaction, shock wave, Mach steam, nearby explosion, shaped obstacle. Summary The paper presents an investigation on the contact pressure distribution for a shaped buried structure at a short standoff distance from an explosion source and examines the effect of the medium properties on the pressure field and analyzes the structure's response. The analysis is based on a formulation that incorporates the modified coupled Godunov method, a variational difference approach for the soil-structure interaction. The numerical simulations demonstrate that for a short standoff distance and high pressures that are characterized by a steep growth of pressure in the equation of state beyond the full compaction point, a maximum value on the envelope of the pressure distributions along both rigid and flexible shaped (cylindrical) obstacles is located at some distance away from the axis of symmetry. The pressure envelope on the structure in that case has one or two local peaks. The pressure distribution analysis enhances our understanding that this phenomenon is caused by the Mach stem effect appearing in a soil medium with significant hardening. The second peak at the envelope of the pressures appears along a shaped structure only and has not been observed for planar obstacles (buried walls). This phenomenon is caused by the secondary Mach stem effect caused by the structure curvature. It is also demonstrated that the type of peak pressure envelope significantly affects the final shape of the explosive cavity. When the Mach stem phenomenon takes place, the structure affects larger and sharper deformations of the cavity front part, sometimes accompanied with a reverse curvature, thus forming a kidney shape cavity. Otherwise, the cavity maintains its cylindrical shape during the entire process. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £45 +P&P)
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