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A transient non-linear dynamics analysis of the detonation of a landmine buried to different depths in water-saturated sand is carried out in order to determine the resulting impulse loading. The results obtained are compared with their experimental counterparts obtained using the vertical impulse measurement fixture (VIMF), a structural mechanical device that enables direct experimental determination of the blast-loading impulse. The mechanical response of the structural steel used in the construction of the VIMF and the hydrodynamic response of the TNT high-energy high-pressure detonation products generated during detonation of a mine and of the air surrounding the VIMF are represented using the standard materials models available in the literature. The mechanical response of the sand surrounding the mine, on the other hand, is represented using the present authors' recent modified compaction model [1], which incorporates the effects of degree of saturation and the rate of deformation, two important effects, that are generally neglected in standard constitutive models for sand. The results obtained indicate that the use of the modified compaction model yields a substantially better agreement with the experimentally determined impulse loads over the use the original compaction model. Furthermore, the results suggest that, in the case of fully saturated sand, the blast loading is of a bubble type rather than of a shock type, i.e. it resembles under-water explosion.

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The kinematic response (including plastic deformation, failure initiation and fracture) of a soft-skinned vehicle (represented by a F800 series single-unit truck) to the detonation of a landmine shallow-buried in (either dry or saturated sand) underneath the vehicle's front right wheel is analyzed computationally. The computational analysis included the interactions of the gaseous detonation products and the sand ejecta with the vehicle and the transient non-linear dynamics response of the vehicle. A frequency analysis of the pressure versus time signals and visual observation clearly show the differences in the blast loads resulting from the landmine detonation in dry and saturated sand as well as the associated kinematic response of the vehicle. It is noted that the dominant vehicle structural response to the blast is similar to the first torsional structural mode shape obtained through an eigenvalue analysis of the system. Tailoring the vehicle modal response may result in more desirable modes of failure.