The strain rate effect of an open cell aluminum foam

Han, Fuzhu; Cheng, Hefa; Wang, Qiang; Li, Zhibin

doi:10.1007/s11661-005-0180-6

Cited by 21 publications

(9 citation statements)

References 26 publications

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“…A limited rate sensitivity is found for Alporas foam and honeycomb, which is mainly due to inertia effects in the successive buckling of the cell walls (Zhao and Abdennadher, 2004;Han et al, 2005). Nickel hollow spheres exhibit also a rate sensitivity that is believed to be due to the rate sensitivity of the cell wall material.…”

Section: Discussionmentioning

confidence: 99%

Shock enhancement of cellular structures under impact loading: Part I Experiments

Elnasri

Pattofatto

Zhao

et al. 2007

Journal of the Mechanics and Physics of Solids

168

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This paper aims at showing experimental proof of the existence of a shock front in cellular structures under impact loading, especially at low critical impact velocities around 50 m/s. First, an original testing procedure using a large diameter Nylon Hopkinson bar is introduced. With this large diameter soft Hopkinson bar, tests under two different configurations (pressure bar behind/ahead of the supposed shock front) at the same impact speed are used to obtain the force/time histories behind and ahead of the assumed shock front within the cellular material specimen.Stress jumps (up to 60% of initial stress level) as well as shock front speed are measured for tests at 55 m/s on Alporas foams and nickel hollow sphere agglomerates, whereas no significant shock enhancement is observed for Cymat foams and 5056 aluminium honeycombs. The corresponding rate sensitivity of the studied cellular structures is also measured and it is proven that it is not responsible for the sharp strength enhancement.A photomechanical measurement of the shock front speed is also proposed to obtain a direct experimental proof. The displacement and strain fields during the test are obtained by correlating images shot with a high speed camera. The strain field measurements at different times show that the shock front discontinuity propagates and allows for the measurement of the propagation velocity. ARTICLE IN PRESSwww.elsevier.com/locate/jmps 0022-5096/$ -see front matter r All the experimental evidences enable us to confirm the existence of a shock front enhancement even at quite low impact velocities for a number of studied materials. r

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Section: Discussionmentioning

confidence: 99%

Shock enhancement of cellular structures under impact loading: Part I Experiments

Elnasri

Pattofatto

Zhao

et al. 2007

Journal of the Mechanics and Physics of Solids

168

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“…It has been shown that there exists a zone where the material ''particle velocity", ''stress" and ''strain" are discontinuous when the crushing velocity exceeds a critical value and that the one-dimensional shock theory tends to overestimate slightly the crushing stress and energy absorbed. In this paper, considering the structural features of hexagonal-cell honey- Han et al (2005) comb, a relatively precise definition of the ''particle" velocity, local engineering strain and engineering stress is introduced to illustrate the plateau stress and the total dissipated energy. It is very useful and explicit to know the engineering stress and strain field in the whole honeycomb along the loading direction.…”

Section: Introductionmentioning

confidence: 99%

A numerical study on the rate sensitivity of cellular metals

Liu

Zheng

et al. 2009

International Journal of Solids and Structures

119

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a b s t r a c tMetallic foams have non-linear deformation behavior, which make them attractive in many applications. Many experimental researches on the dynamic behavior and rate sensitivity of cellular metals have been reported in the literature, but they contain conflicting, and sometimes confusing, conclusions on the strain-rate and inertia effect of cellular metals. In this paper, the dynamic crushing behavior of 2D Voronoi honeycomb is studied by finite element method. The influences of inertia, strain hardening and strain-rate hardening of metal matrix on the deformation mode and plateau stress of the honeycomb are investigated. Three deformation modes are found in different velocity ranges. According to the numerical results, it is found that the plateau stress increases significantly with the increase of impact velocity due to non-uniform deformation induced by inertia. The strain-hardening effect is slight in our numerical tests and the rate effect of the honeycomb is obviously weaker than that of the cell wall material.

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“…In general terms, the rate sensitivity of cellular metals may be affected by micro-inertia [9,[23][24][25]; rate sensitivity of cellwall material [24,26,27]; compression of entrapped gas in cells [6,11]; and other factors, such as inertia and shock wave effects [28] that may change the deformation mode of the material. Su et al [22] suggested that, given the "flat topped" quasi-static stress versus strain curve of aluminum foams, micro-inertia plays little role under dynamic loading [10].…”

Section: Resultsmentioning

confidence: 99%

Strain Rate Behavior of Closed-Cell Al-Si-Ti Foams: Experiment and Numerical Modeling

Zhang

Zhao

et al. 2015

Mechanics of Advanced Materials and Structures

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We present a combined experimental and numerical study on the strain rate effect of closed-cell Al-Si-Ti foams having different relative densities fabricated using the powder metallurgy foaming technique. The high strain rate tests were conducted with split Hopkinson pressure bar technique at 800 to 2500 s −1 . Two-dimensional mesoscale finite element models were created from tomographic images of the homologous foam. The rate sensitivity of the foam originates mainly from that of its parent material, increasing with increasing relative density. Stress elevation due to other effects, such as micro-inertia, shock wave, and gas pressure in individual cells, is negligible.

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The strain rate effect of an open cell aluminum foam

Cited by 21 publications

References 26 publications

Shock enhancement of cellular structures under impact loading: Part I Experiments

Shock enhancement of cellular structures under impact loading: Part I Experiments

A numerical study on the rate sensitivity of cellular metals

Strain Rate Behavior of Closed-Cell Al-Si-Ti Foams: Experiment and Numerical Modeling

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