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The purpose of this paper is to analyze, computationally, the kinematic response (including large‐scale rotation and deformation, buckling, plastic yielding, failure initiation, fracture and fragmentation) of a pick‐up truck to the detonation of a landmine (shallow‐buried in one of six different soils, i.e. either sand, clay‐laden sand or sandy gravel, each in either dry or water‐saturated conditions, and detonated underneath the vehicle) using ANSYS/Autodyn, a general‐purpose transient non‐linear dynamics analysis software.

The computational analysis, using ANSYS/Autodyn, a general‐purpose transient non‐linear dynamics analysis software, 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.

The results obtained 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 was also found that the low frequency content of the blast loads which can match the whole‐vehicle eigen modes is quite small so that resonance plays a minor role in the kinematic/ballistic response of the vehicle. Furthermore, it was demonstrated that mine blast analytical loading functions which are often used in transient non‐linear dynamic analyses have limited value when used in the analyses of a complete vehicle.

This is the first time that the kinematic response of a pick‐up truck to the detonation of a shallow‐buried landmine (using a full‐scale/complete model) has been analyzed computationally.

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.

Detonation of landmines buried to different depths in water‐saturated sand is analyzed computationally using transient non‐linear dynamics simulations in order to quantify impulse loading. The computational results are compared with the corresponding experimental results obtained using the Vertical Impulse Measurement Fixture (VIMF), a structural mechanical device that enables direct experimental determination of the blast‐loading impulse. The structural‐dynamic/ballistic response of the Rolled Homogenized Armor (RHA) used in the construction of the VIMF witness plate and the remainder of the VIMF and the hydrodynamic response of the TNT high‐energy explosive of a mine and of the air surrounding the VIMF are represented using the standard materials models available in literature. The structural‐dynamic/ballistic response of the sand surrounding the mine, on the other hand, is represented using our recent modified compaction model which incorporates the effects of degree of saturation and the rate of deformation, two important effects which are generally neglected in standard material 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. the detonation‐induced momentum transfer to the witness plate is accomplished primarily through the interaction of the sand‐over‐burden (propelled by the high‐pressure expanding gaseous detonation by‐products) with the witness plate.

The recently proposed concept solution for improving blast-survivability of the light tactical military vehicles is critically assessed using combined finite-element/discrete-particle computational methods and tools. The purpose of this paper is to propose a concept that involves the use of side-vent-channels attached to the V-shaped vehicle underbody. Since the solution does not connect the bottom and the roof or pass through the cabin of a light tactical vehicle, this solution is not expected to: first, reduce the available cabin space; second, interfere with the vehicle occupants’ ability to scout the surroundings; and third, compromise the vehicle’s off-road structural durability/reliability. Furthermore, the concept solution attempts to exploit ideas and principles of operation of the so-called “pulse detonation” rocket engines in order to create a downward thrust on the targeted vehicle.

To maximize the downward thrust effects and minimize the extent of vehicle upward movement, standard engineering-optimization methods and tools are employed for the design of side-vent-channels.

The results obtained confirmed the beneficial effects of the side-vent-channels in reducing the blast momentum, although the extent of these effects is relatively small (3-4 percent).

To the authors’ knowledge, the present work is the first public-domain report of the side-vent-channel blast-mitigation concept.

The purpose of this paper is computer-aided engineering analysis of the recently proposed side-vent-channel concept for mitigation of the blast-loads resulting from a shallow-buried mine detonated underneath a light tactical vehicle. The concept involves the use of side-vent-channels attached to the V-shaped vehicle underbody, and was motivated by the concepts and principles of operation of the so-called “pulse detonation” rocket engines. By proper shaping of the V-hull and side-vent-channels, venting of supersonically expanding gaseous detonation products is promoted in order to generate a downward thrust on the targeted vehicle.

The utility and the blast-mitigation capacity of this concept were examined in the prior work using computational methods and tools which suffered from some deficiencies related to the proper representation of the mine, soil, and vehicle materials, as well as air/gaseous detonation products. In the present work, an attempt is made to remove some of these deficiencies, and to carry out a bi-objective engineering-optimization analysis of the V-hull and side-vent-channel shape and size for maximum reduction of the momentum transferred to and the maximum acceleration acquired by the targeted vehicle.

Due to the conflicting nature of the two objectives, a set of the Pareto designs was identified, which provide the optimal levels of the trade-off between the two objectives.

To the authors’ knowledge, the present work is the first public-domain report of the side-vent-channel blast-mitigation concept.

The purpose of this paper is to carry out a design-optimization analysis of the recently proposed side-vent-channel concept/solution for mitigation of the blast loads resulting from a shallow-buried mine detonated underneath a light tactical vehicle. Within this concept/solution, side-vent-channels attached to the V-shaped vehicle underbody are used to promote venting of ejected soil and supersonically expanding gaseous detonation products. This effect generates a downward thrust on the targeted vehicle, helping the vehicle survive mine-detonation-induced impulse loading.

The utility and the blast-mitigation capacity of this concept are investigated computationally using coupled finite-element/discrete-particle computational methods and tools. To maximize the blast-mitigation capacity of the solution (as defined by a tradeoff between the maximum reductions in the detonation-induced total momentum transferred to, and the acceleration acquired by, the target vehicle), the geometry and size of the side-vent-channel solution are optimized.

It is found that by optimizing the shape and size of the side-vent-channels, their ability to mitigate blast can be improved, but the overall blast-mitigation potential of the side-vent-channel solution remains relatively modest.

To the authors’ knowledge, the present work is the first attempt to combine the finite-element/discrete-particle analysis with optimization in order to refine the side-vent-channel blast-mitigation concept.

Development of military vehicles capable of surviving shallow-buried explosive blast is seldom done using full-scale prototype testing because of the associated prohibitively high cost, the destructive nature of testing, and the requirements for large-scale experimental-test facilities and a large crew of engineers committed to the task. Instead, tests of small-scale models are generally employed and the model-based results are scaled up to the full-size vehicle. In these scale-up efforts, various dimensional analyses are used whose establishment and validation requires major experimental testing efforts and different-scale models. The paper aims to discuss these issues.

In the present work, a critical assessment is carried out of some of the most important past efforts aimed at developing the basic dimensional analysis formulation for the problem of impulse loading experienced by target structures (e.g. vehicle hull) due to detonation of explosive charges buried to different depths in sand/soil (of different consistency, porosity, and saturation levels).

It was found that the analysis can be substantially simplified if only the physical parameters associated with first-order effects are retained and if some of the sand/soil parameters are replaced with their counterparts which better reflect the role of soil (via the effects of soil compaction in the region surrounding the explosive and via the effects of sand-overburden stretching and acceleration before the associated sand bubble bursts and venting of the gaseous detonation products takes place). Once the dimensional analysis is reformulated, a variety of experimental results pertaining to the total blast impulse under different soil conditions, charge configurations, charge deployment strategies, and vehicle ground clearances are used to establish the underlying functional relations.

The present work clearly established that due to the non-dimensional nature of the quantities formulated, the established relations can be utilized across different length scales, i.e. although they are obtained using mainly the small-scale model results, they can be applied at the full vehicle length scale.

A new concept solution for improving blast survivability of the light tactical military vehicles is proposed and critically assessed using computational engineering methods and tools.

The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called “pulse detonation” rocket engines, in particular, and is an extension of the recently introduced so-called “blast chimney” concept (essentially a vertical channel connecting the bottom and the roof and passing through the cabin of a light tactical vehicle). Relative to the blast-chimney concept, the new solution offers benefits since it does not compromise the cabin space or the ability of the vehicle occupants to scout the environment and, is not expected to, degrade the vehicle’s structural durability/reliability. The proposed concept utilizes side vent channels attached to the V-shaped vehicle underbody whose geometry is optimized with respect to the attainment of the maximum downward thrust on the vehicle. In the course of the channel design optimization, analytical and computational analyses of supersonic flow (analogous to the one often used in the case of the pulse detonation engine) are employed.

The preliminary results obtained reveal the beneficial effects of the side channels in reducing the blast momentum, although the extent of these effects is quite small (2-4 per cent).

To the authors’ knowledge, the present work is the first exploration of the side-vent-channels concept for mitigating the effect of buried-mine explosion on a light tactical vehicle.

The purpose of this paper is to address the problem of substitution of steel with fiber-reinforced polymer-matrix composite in military-vehicle hull-floors, and identifies and quantifies the associated main benefits and shortcomings.

The problem is investigated using a combined finite-element/discrete-particle computational analysis. Within this analysis, soil (in which a landmine is buried), gaseous detonation products and air are modeled as assemblies of discrete, interacting particles while the hull-floor is treated as a Lagrangian-type continuum structure. Considerable effort has been invested in deriving the discrete-material properties from the available experimental data. Special attention has been given to the derivation of the contact properties since these, in the cases involving discrete particles, contain a majority of the information pertaining to the constitutive response of the associated materials. The potential ramifications associated with the aforementioned material substitution are investigated under a large number of mine-detonation scenarios involving physically realistic ranges of the landmine mass, its depth of burial in the soil, and the soil-surface/floor-plate distances.

The results obtained clearly revealed both the benefits and the shortcomings associated with the examined material substitution, suggesting that they should be properly weighted in each specific case of hull-floor design.

To the authors’ knowledge, the present work is the first public-domain report of the findings concerning the complexity of steel substitution with composite-material in military-vehicle hull-floors.

A large‐strain/high‐deformation rate model for clay‐free sand recently proposed and validated in our work [1,2], has been extended to sand containing relatively small (< 15vol.%) of clay and having various levels of saturation with water. The model includes an equation of state which represents the material response under hydrostatic pressure, a strength model which captures material behavior under elastic‐plastic conditions and a failure model which defines conditions and laws for the initiation and evolution of damage/failure in the material. The model was validated by comparing the computational results associated with detonation of a landmine in clayey sand (at different levels of saturation with water) with their computational counterparts.