Sand column impact onto a Kolsky pressure bar

Park, S.; Uth, T.; Fleck, N.A.; Wadley, H.N.G.; Deshpande, V.S.

doi:10.1016/j.ijimpeng.2013.07.003

Cited by 28 publications

(36 citation statements)

References 24 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%

“…Fig. 2 depicts the experimental set-up, which comprises four main components (from right to left): (i) a gas gun to fire a solid projectile, which then accelerates the piston of (ii) a slug launcher apparatus based upon that developed by Park et al (2013); (iii) a WC slug that initially rests inside the cylindrical cavity of the launcher; and (iv) the beams clamped to the support rig, which is equipped with force sensors to measure the transferred momentum. We now proceed to describe the manufacture of the beams and each of the four components listed above.…”

Section: Experimental Protocolmentioning

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%

“…Since we cannot refer the tracer particles back to their positions in the undeformed slug, we cannot determine the density distribution within the slugs from the measurements reported here. In order to determine I o we adopt a strategy motivated by measurements reported for slugs of silica sand by Park et al (2013). They impacted the silica sand slugs against a direct-impact Kolsky bar and measured the momentum transmitted into the bar by the slug, in addition to making a direct measurement of the free-field momentum from the velocity and density distribution within the slug.…”

Section: Temporal Evolution Of the Wc Slugsmentioning

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: Experimental Protocolmentioning

confidence: 99%

Section: Slug Launchermentioning

confidence: 99%

Section: Temporal Evolution Of the Wc Slugsmentioning

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 higher local loading of the sandwich by sand particle reflection during dynamic evolution of the panel's surface topology, amplified local core crushing and face sheet stretching leading to fracture, and focused attention upon the need for a deeper understanding of the soil structure interaction (SSI) effect. The impact of sand particle columns against rigid surfaces at zero obliquity has been experimentally investigated by Park et al [39]. Using wet and dry sand column's with impact velocities up to 100 ms À1 , they found that the pressure applied by the sand was hydrodynamic and approximately equal to rv 2 (where r was the sand column density and v its incident velocity); the stagnation pressure of the sand.…”

Section: Introductionmentioning

confidence: 99%

Impulse transfer during sand impact with a cellular structure

Holloman

Deshpande

Wadley

2015

International Journal of Impact Engineering

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a b s t r a c tCompressible cellular metal sandwich structures made from a 3D assembly of square cross section 6061 T6 aluminum alloy tubes, and face sheets of the same alloy have been attached to a vertical pendulum and impacted by synthetic wet sand with an incident velocity of~300 ms À1 . The transmitted impulse of samples with thick (relatively rigid) and thin face sheets are compared to that transferred by an incompressible solid aluminum test block of the same dimensions. A discrete particle-based simulation method was used to simulate the experiments and to investigate the soil particle e structure interaction with the cellular structures. The simulated results agreed very well with experimental data; both showed that the impulse transferred to cellular structures with a 22 MPa core strength was 10e15% less than that transferred to a solid block of similar dimensions. However, the simulations reveal that the some of this apparent mitigation resulted from a subtle sand interaction between the bottom of the test structure and the sand box used for the tests. When this sand box effect was eliminated in the simulations, a small impulse reduction from cellular structures with thin face sheets was still observed. However, this was found to be a result of dynamic deflection of the edges of the front face sheet. When this effect was eliminated (by the use of a rigid front face), the simulations showed a small (5%) impulse reduction occurred for cellular structure whose compressive strength was much less than the pressure applied by the sand. This was a consequence of rapid core compression which increased the travel distance (and lateral spreading) of late arriving sand during the sand loading process. Weak cellular structures, that suffered significant crushing, also reduce the impulse transfer rate.

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