Impulse loading of near-field shallow-buried explosions

• Main Author: Beetge, Frans Jacobus
• Other Authors: Nurick, Gerald N
• Format: Dissertation
• Language: English
• Published: University of Cape Town 2014
• Subjects: Mechanical Engineering
• Online Access: http://hdl.handle.net/11427/5555

Includes bibliographical references (leaves 202-208). === Prediction of the total impulse for a mine-protected vehicle must be empirically determined for South African Paardefontein soil pit soil at the start-up phase of a new vehicle project, particularly when experimental data are not yet available for the calibration of computational efforts. The total impulse on a mine-protected vehicle is influenced by a number of factors, such as size of the exposed target area, explosive mass, explosive diameter to height ratio, standoff distance, depth of burial, and soil properties. This investigation entails the development of an empirical equation for predicting total impulse by applying regression analysis. A series of comparative test results were obtained with the Scientific Instrumented Impulse Measurement Apparatus (SIIMA) for TNT equivalent surrogate mines of 2.13 kg - 8 kg mass and diameter to height ratio of 5: 1, and are reported. The lethal aspects of buried mines (target loading mechanisms), such as the detonation shock load, impact load and distributed load, are identified and discussed. Important parameters influencing anti-vehicular blasts, such as standoff distance, soil effects, mine composition and geometry and target shape, are investigated and reported. In conclusion, a SIIMA empirical equation is established which, although limited in standoff distance, can be used as an affordable and quick tool to calculate the vertical impulse on a flat bottom mine-protected vehicle. The SIIMA results show reasonable agreement with the published data of Westine et al (1985) (Braid [1], Williams et al [2] and Williams and Poon [3]), and with the computational predictions provided by the CSIR DPSS-LS. The results provide a better understanding of the complex behaviour of shallow-buried mines in dry sand as an anti-vehicular mine threat, when considering parameters such as standoff distance and depth of burial for constant conditions of explosive aspect ratio (diameter to height values).