Optimal porosity for impact squeeze of soft layers imbibed with liquids

Cicone, Traian; Pascovici, M. D.; Melciu, Catalin; Turtoi, P

doi:10.1016/j.triboint.2019.02.018

Cited by 8 publications

(3 citation statements)

References 17 publications

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“…In the last decades, theoretical ( [11], [12]) and experimental results ( [13], [14]), have shown that using porous and deformable materials, imbibed with fluids, greatly increases their impact damping capacity making the evaluation process of the material's permeability variation with compression level an activity of great importance. The evaluation of this variation has been possible with the use of complex experimental devices [15] and has proved to be an useful and thorough approach, but also time and resource consuming.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and structural characterisation of a 3D warp-knitted spacer fabric subjected to compression

Lupu¹,

Fatu²,

Henry³

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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3D warp-knitted spacer fabrics show a growing importance, especially in cushioning or impact damping applications. The use of 3D fabrics saturated with fluids improves their impact damping capabilities and, in this case, evaluating the variation of material’s permeability with compression level is of great importance. In the past few years, our efforts were focused on evaluating this variation with the use of complex experimental devices, an approach that has proven to be very useful and thoroughly, but also time and resource consuming. Through this new initiative we aim to make a step further in our attempt to model the behaviour of dry or imbibed 3D warp-knitted spacer fabrics by considering their complex internal structure. A 3D model was built, based on a CT scan of a commercially available 3D fabric, which allowed us to simulate using the finite element method the structure’s response to different compression levels and conditions.

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Section: Introductionmentioning

confidence: 99%

Mechanical and structural characterisation of a 3D warp-knitted spacer fabric subjected to compression

Lupu¹,

Fatu²,

Henry³

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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“…The resistance to compression of porous materials subjected to squeeze is augmented when imbibed. This effect is produced by the flow resistance through the open pores and is dependent on the variation of the permeability with the compression level [3]. This force is superimposed on the elastoplastic forces generated during the compression of the solid structure (fibers, cell walls, particles etc.…”

Section: Introductionmentioning

confidence: 99%

Instrumentation and preliminary evaluation of a drop tower tester for low and medium impact energy

Nechita

Turtoi²,

Cicone³

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Soft, porous structures imbibed with liquids have good impact attenuation properties. Literature survey reveals a continuous need for new impact tests to assess impact response for the newly developed soft, porous materials. This paper presents a versatile drop tower tester which is based on an impactor that slides inside a transparent tube. The test rig is equipped with high-speed transducers (force and acceleration) and a laser system used to measure the deformation of the experimental cell. A high-speed camera records subtle details of the impact that are not are visible with the naked eye. Preliminary experiments made on dry and imbibed soft fibrous tridimensional textile have shown good repeatability during impact. The experiments presented validate the experimental procedure, based on the analysis of the contact force-displacement curve, acceleration, and impact force-transmitted force. The obtained results demonstrate that true impact response is described with high resolution.

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“…Recent laboratory experiments made with damping cells consisting of porous discs imbibed with Newtonian liquids have shown high capacity of force attenuation at impact [8]. However, if the porous is partially imbibed, the cells cannot be used in vertical position due to the irregular imbibition provoked by gravitational forces.…”

Section: Introductionmentioning

confidence: 99%

Squeeze Flow of Bingham Fluids through Reticulated, Compressed Foams

2019

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The paper presents experimental and theoretical results for the planar squeeze flow of a finite volume of viscoplastic material through a highly deformable porous layer. The central zone of an annular disc made of a reticulated polyurethane foam with high porosity (ε > 0.97) was fully filled with tooth paste. The porous disc placed between two flat, impermeable, parallel, and rigid discs was subjected to compression and the normal force was recorded. After compression, the radial extension of the squeezed fluid was measured. The visualisation of the compressed disc managed to provide evidence of a tortuous flow inside the porous structure. An original analytical model is proposed for the prediction of the front of the flow inside the porous layer and corresponding resistant normal force. The model combines the Covey and Stanmore (1981) model for squeeze flow of a Bingham fluid inside the central zone, with an original approach for flow through the reticulated foams, based on the concept of "equivalent flow tubes" with variable tortuosity. This explorative investigation is of interest for innovative shock absorbers. The model validity covers both low and high plasticity numbers and was experimentally validated for low speed.

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Optimal porosity for impact squeeze of soft layers imbibed with liquids

Cited by 8 publications

References 17 publications

Mechanical and structural characterisation of a 3D warp-knitted spacer fabric subjected to compression

Mechanical and structural characterisation of a 3D warp-knitted spacer fabric subjected to compression

Instrumentation and preliminary evaluation of a drop tower tester for low and medium impact energy

Squeeze Flow of Bingham Fluids through Reticulated, Compressed Foams

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