The response of quadrangular plates to buried charges

Pickering, E.G.; Yuen, S. Chung Kim; Nurick, G.N.; Haw, P.

doi:10.1016/j.ijimpeng.2012.05.007

Cited by 44 publications

(44 citation statements)

References 26 publications

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“…(iv) Measurements reported in the literature (e.g. Pickering et al (2012)) only measure the z-component of the transmitted momentum using a ballistic pendulum. Thus, the measurements typically underestimate the transmitted resultant momentum -the measurements reported here show that a significant fraction of the momentum is transmitted in the y-direction.…”

Section: Reference Measurements Of Momentum Transfermentioning

confidence: 99%

“…Several strategies have been recently investigated to improve the blast resistance of these underbody structures without increasing the overall weight of the vehicles. These include: (i) replacing the monolithic underbody by a sandwich panel Liu et al, 2013;Rimoli et al, 2011;Wadley et al, 2013), (ii) increasing the so-called stand-off of the vehicle floor from the ground (Børvik et al, 2011;Dharmasena et al, 2013;Hlady, 2004;Pickering et al, 2012), and (iii) inclining the underbody with respect to the ground by making use of a V-shaped hull design (Anderson et al, 2011;Bergeron and Tremblay, 2000;Follett, 2011;Fox et al, 2011) as sketched in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

“…Numerical calculations Liu et al, 2013) have shown that this performance benefit is not related to a fluid-structure interaction effect as in the water blast problem, but arises from the higher bending stiffness and strength of sandwich structures compared to monolithic counterparts of equal mass per unit area. Experimental studies have also shown that increasing the stand-off distance between the target and the explosive/ground decreases the deflections of monolithic plates (Børvik et al, 2011;Fourney et al, 2005;Pickering et al, 2012) and sandwich panels . Traditionally, this decrease has been attributed to a reduction in the momentum transfer from the ejected soil and detonation products to the target due to the spherical expansion of the ejecta; see experiments of Hlady (2004) for rigid targets and Pickering et al (2012) for deformable plates.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental studies have also shown that increasing the stand-off distance between the target and the explosive/ground decreases the deflections of monolithic plates (Børvik et al, 2011;Fourney et al, 2005;Pickering et al, 2012) and sandwich panels . Traditionally, this decrease has been attributed to a reduction in the momentum transfer from the ejected soil and detonation products to the target due to the spherical expansion of the ejecta; see experiments of Hlady (2004) for rigid targets and Pickering et al (2012) for deformable plates. However, there is an additional factor that leads to reduced deflections with increasing stand-off.…”

Section: Introductionmentioning

confidence: 99%

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The effect of inclination and stand-off on the dynamic response of beams impacted by slugs of a granular material

Uth

Wadley

Deshpande

2015

International Journal of Solids and Structures

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a b s t r a c tThe dynamic response of end-clamped sandwich and monolithic beams to impact by high-velocity tungsten carbide (WC) particle columns (slugs) has been measured with the aim of developing an understanding of the interaction of ejecta from a shallow-buried explosion with structures. The monolithic beams were made from stainless steel, while the sandwich beams of equal areal mass comprised stainless steel face sheets and an aluminium honeycomb core. High-speed imaging was used to measure the transient transverse deflection of the beams, to record the dynamic modes of deformation, and to observe the flow of the WC particles upon impact. The experiments show that sandwich beams deflect less than the monolithic beams both in normal and inclined impact situations. Moreover, the deflections of all beams in the inclined orientation were less than their respective deflections in the normal orientation at the same slug velocity. Intriguingly, the ratio of the deflection of the sandwich to monolithic beams remains approximately constant with increasing slug velocity for inclined impact but increases for normal impact; i.e. inclined sandwich beams retain their advantage over monolithic beams with increasing slug velocity. Dynamic force measurements reveal that (i) the momentum transferred from the impacting slug to both monolithic and sandwich beams is the same, and (ii) the interaction between the impacting particles and the dynamic deformation of the inclined monolithic and sandwich beams results in a momentum transfer into these beams that is equal to or greater than the momentum of the slug. These experimental findings demonstrate that contrary to intuition and widespread belief, the performance enhancement obtained from employing beam inclination is not due to a reduction in transferred momentum. Finally, we show that increasing the stand-off distance decreases beam deflections. This is because the slugs lengthen as they traverse towards their target and thus the duration of loading is extended with increasing standoff. However, combining increased stand-off with sandwich construction does not yield the synergistic benefits of sandwich construction combined with beam inclination.

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Section: Reference Measurements Of Momentum Transfermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effect of inclination and stand-off on the dynamic response of beams impacted by slugs of a granular material

Uth

Wadley

Deshpande

2015

International Journal of Solids and Structures

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“…The design of vehicle underbody structures that can survive the impact of soil ejected by shallow-buried explosives has been a topic of considerable interest for many years. Numerous strategies have been proposed to improve the impulsive load resistance of these underbody structures including (i) replacing the monolithic underbody by sandwich panels [1][2][3][4], (ii) increasing the stand-off distance of the vehicle floor from the ground [1,[5][6][7], and (iii) inclining the underbody with respect to the ground by making use of a V-shaped hull design [8][9][10][11] as sketched in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Effect of surface properties on momentum transfer to targets impacted by high-velocity sand slugs

Goel

Uth

Wadley

et al. 2017

International Journal of Impact Engineering

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The response of dry and water saturated sand slugs impacting normally oriented and inclined rigid-stationary targets with four different surface coatings is measured with an emphasis on the quantification of the momentum transmitted from the slugs into the targets. The targets were coated with Alumina, PTFE, Aluminium or sandpaper layers in order to investigate the effect of varying surface hardness and surface roughness. In all the cases, the fraction of the slug momentum transferred into the target was equal for dry and water saturated sand slugs and also independent of the slug velocity over the range that is investigated here. For normal impacts, the surface coatings had no measurable influence on the momentum transfer into the targets and this was attributed to the symmetry of the impact event. However, the break of symmetry in the inclined impact cases resulted in two non-zero components of the net transmitted momentum into the targets and a strong influence of the surface coatings. This is attributed to friction between the sand particles and the target surface with the resultant transmitted momentum increasing in the order Alumina to PTFE to Aluminium to sandpaper surface coatings. In all cases, the transmitted momentum was less than the corresponding value under normal impact. Coupled discrete particle/ Lagrangian simulations of these experiments with the sand particles modelled as spheres captured the normal impact measurements with a high degree of fidelity. However, the simulations underestimated the transmitted momentum for the inclined impacts especially for the rough surface coatings such as the sandpaper: increasing the friction coefficient between the particles and the target in the simulations did not improve the predictions. We demonstrate that this discrepancy is due to the spherical particle assumption: in the experiments the sand particles are sub-spherical and this reduces the tendency of particles to roll on the target surface and thereby increases frictional interactions. Increasing the radius of gyration of particles decreased the discrepancy between the measurements and the predictions but yet could not accurately predict all components of the transmitted momentum. Most numerical calculations tend to use spherical particles to represent the impacting granular media. However, this study demonstrates the need to appropriately parameterise particle shape in such discrete particle calculations to accurately capture the granular media/ structure interactions.

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