Fracture energies of composite propellants

Marom, G.; Harel, H.; Rosner, J.

doi:10.1002/app.1977.070210619

Cited by 7 publications

(4 citation statements)

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“…When the energy in the region of the crack tip is elastically recoverable the contribution of W λ A 0 /2 t component is negligible compared with λf / t , and λ = 1. Thus, in this case, eqn reduces to

γ = \frac{f}{t} .

…”

Section: Methodsmentioning

confidence: 99%

Delamination fracture toughness of UHMWPE fibers/polyurethane laminates interleaved with carbon nanotube‐reinforced polyurethane films

Lyashenko-Miller

Marom

2016

Polymers for Advanced Techs

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The main cause for failure of composite laminates is delamination under shear or transverse loading. A common approach to prevent such failure is to introduce a discrete interleaf at the midplane of the laminate in order to increase its fracture toughness and, consequently, its resistance to delamination. Accordingly, a study of Mode I fracture toughness of ultra-high molecular weight polyethylene fibers/polyurethane matrix composite laminates interleaved with thin polyurethane films reinforced with either untreated or functionalized carbon nanotubes is presented here. The results show that-depending on the surface treatment of the carbon nanotubes-the introduction of an interleaf at the midplane of the laminate generates a significant improvement of the Mode I initiation and propagation fracture toughness compared to the non-interleaved laminates and to laminates interleaved with un-reinforced polyurethane films. The Mode I fracture toughness results correlate with the "trouser-leg" fracture surface energy of the films.

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γ = \frac{f}{t} .

…”

Section: Methodsmentioning

confidence: 99%

Delamination fracture toughness of UHMWPE fibers/polyurethane laminates interleaved with carbon nanotube‐reinforced polyurethane films

Lyashenko-Miller

Marom

2016

Polymers for Advanced Techs

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“…This shear zone is similar, but physically much bigger than the distortion on guillotined edges due to blunt blades [14]. The work done, dW~l in the shear zones along a length dx of both legs is given by £ dW~l = 2dxst 6dg (12) where g is the equivalent strain in the shear zone, which is ~'0/~/3, "~0 being the maximum shear strain. Using the power law equation (5) it can be shown that the specific essential work performed in shear deformation %1 = dVVel/tdx is given by…”

Section: P % + (11) 7=2mentioning

confidence: 98%

“…1 is first developed by Rivlin and Thomas [8] for use with rubber. It has since become a favourite test piece geometry for determination of the specific essential work of fracture (We) for elastic thin sheet materials of various kinds in the out-of-plane mode III tearing [9][10][11][12]. By considering an energy balance of the fracture process it can be easily shown that if the width of the legs (B) is sufficiently large the elastic energy release in the legs is negligible compared to the external work done by the force P, then where t is specimen thickness, u is the displacement of the point of application of the forces and a is the crack length.…”

Section: The Trousers Test For Ductile Tearing Of Sheet Metalsmentioning

confidence: 99%

The essential work of fracture for tearing of ductile metals

1984

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A simple energy balance analysis is presented for the tearing of ductile sheet metals using the trousers test. It is shown that the specific essential work of fracture (w~) for tearing can be estimated by extrapolating the straight line relationship between the tearing force per unit thickness and the trousers leg width to zero leg width. There are two contributions to the specific essential work of fracture: one is due to the localised plastic shearing work in a zone contiguous with the torn edges (%1) and the other is the final out-of-plane tearing work (We2).

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“…Hence, it is commonly assumed that -since λ ≈ 1, the equation is reduced to 23,24 : Impact test was performed by a falling ball instrument. The weight of the ball was 260 g and the falling height was 10.9 m. Test specimens of simulated ballistic glass were prepared by the standard commercial manufacturing process (temperature and pressure) by inserting a…”

Section: Mechanical Characterizationmentioning

confidence: 99%

Hybrid effects in the fracture toughness of polyvinyl butyral-based nanocomposites

Stern

Dyamant²,

Shemer³

et al. 2018

Nanocomposites

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a a the casali center of applied chemistry and the center for Nanoscience and Nanotechnology, the institute of chemistry, the Hebrew University of Jerusalem, Jerusalem, israel; b osG armor R&D, oran safety Glass Ltd, Kibbutz tzuba, israel; c school of materials science and engineering, Nanyang technological University, singapore, singapore ABSTRACT Hybrid polyvinyl butyral (PVB) nanocomposite films comprising surface-treated carbon nanotubes (CNT-COOH) and nanoclays (NC) were tested for their "trouser-leg" fracture toughness in comparison to the values of the respective CNT and NC parent composites and to that of the pristine PVB film. Relative to the fracture toughness of the pristine PVB, the parent composites PVB/CNT-COOH-0.2% and PVB/NC-2% and the PVB/CNT-COOH-0.2%/NC-2% hybrid exhibited 105, 118, and 181% improvements, respectively. These were both impressive fracture toughness improvements and a significant hybrid effect -the latter being only slightly lower than the nominal maximum effect of 223% based on the combined improvements of the parent composites. Part of the samples was tested qualitatively by ball impact test of ballistic glass samples with relevant films. Among these samples, the hybrid film presented the best result. A significant linear correlation between fracture surface energy and roughness values was taken to reflect a fracture resistance mechanism of crack front slowdown by its interactions with nanoparticles.

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Fracture energies of composite propellants

Cited by 7 publications

References 0 publications

Delamination fracture toughness of UHMWPE fibers/polyurethane laminates interleaved with carbon nanotube‐reinforced polyurethane films

Delamination fracture toughness of UHMWPE fibers/polyurethane laminates interleaved with carbon nanotube‐reinforced polyurethane films

The essential work of fracture for tearing of ductile metals

Hybrid effects in the fracture toughness of polyvinyl butyral-based nanocomposites

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