Response of clamped sandwich beams subjected to high-velocity impact by sand slugs

Uth, T.; Deshpande, V.S.

doi:10.1016/j.ijimpeng.2014.02.012

Cited by 24 publications

(17 citation statements)

References 23 publications

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“…In line with observations made for silica sand slugs by Park et al (2013) and Uth and Deshpande (2014), the velocity of the particles within the slugs remains temporally invariant after the slugs fully exit the launcher (i.e. the velocity of the slug is constant over the period during which observations can be made).…”

Section: Temporal Evolution Of the Wc Slugssupporting

confidence: 82%

“…These two observations are rationalised as follows: (i) the loading due to the granular slug is primarily inertial (Park et al, 2013) and thus the impact pressure scales with the square of the particle velocity, i.e. impact pressure increases with v o , and (ii) the loading time scales as L=v o Park et al, 2013;Uth and Deshpande, 2014) and is consequently longer for the lower impact velocity.…”

Section: Temporal Evolution Of the Wc Slugsmentioning

confidence: 99%

“…The launcher was modified from that developed by Park et al (2013) and later employed by Uth and Deshpande (2014); here we briefly describe it with an emphasis on the modifications made as part of this study. A cross-sectional view of the slug launcher is sketched in Fig.…”

Section: Slug Launchermentioning

confidence: 99%

“…However, as discussed in Uth and Deshpande (2014) and Wadley et al (2013), the clamping plates also need to be designed to minimise interference with the WC particles when they flow outwards from the impact site towards the supports. An interference with this flow causes particle redirection and increased momentum transfer, which may result in premature failure near the supports .…”

Section: Design Of the Beam Clampsmentioning

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: Temporal Evolution Of the Wc Slugssupporting

confidence: 82%

Section: Temporal Evolution Of the Wc Slugsmentioning

confidence: 99%

Section: Slug Launchermentioning

confidence: 99%

Section: Design Of the Beam Clampsmentioning

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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“…The launcher was developed by Park et al [27] and later modified by Uth and Deshpande [32] and Uth et al [29]. A cross-sectional view of the slug launcher is sketched in Fig.…”

Section: Slug Launchermentioning

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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Dynamic response of ultralight all-metallic sandwich panel with 3D tube cellular core to shallow-buried explosives

Zhang

Zhao

et al. 2021

Sci. China Technol. Sci.

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The underbody of a vehicle system, either military or civil, is typically made of a relatively thin metallic plate, thus vulnerable to mine blast attacks. To improve the blast resistance, a multitude of protective structures have been proposed as attachments to the thin plate. In the present study, a novel ultralight all-metallic sandwich panel with three-dimensional (3D) tube cellular cores mounted to the vehicle underbody was envisioned as such a protective system. A metallic substrate (mimicking vehicle bottom) was placed above the proposed sandwich panel to construct a sandwich-substrate combinative structure. A series of sandwich panels having 3D tube cellular cores were fabricated via argon protected welding and laser welding. Mechanical responses of the combinative structure subjected to the denotation of 6 kg TNT explosives shallow-buried in dry sand were experimentally measured. Full numerical simulations with the method of finite elements (FE) were subsequently carried out to explore the physical mechanisms underlying the observed dynamic performance and quantify the effects of key geometrical parameters and connection conditions of the protective system. The performance of the proposed sandwich panel under shallow-buried explosives was also compared with competing sandwich constructions having equal mass. Finally, a preliminary optimal design of the 3D tube cellular core was carried out.

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Response of clamped sandwich beams subjected to high-velocity impact by sand slugs

Cited by 24 publications

References 23 publications

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

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

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

Dynamic response of ultralight all-metallic sandwich panel with 3D tube cellular core to shallow-buried explosives

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