Stress–strain modeling of EPS geofoam for large-strain applications

Hazarika, Hemanta

doi:10.1016/j.geotexmem.2005.11.003

Cited by 80 publications

(20 citation statements)

References 11 publications

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“…The σ C0 values from the straight line fit were increased by 20% before entering into Table 2. These values are consistent with literature impact data for the respective densities [31], [18] …”

Section: Helmet Materials Propertiessupporting

confidence: 92%

FEA of oblique impact tests on a motorcycle helmet

Mills

Wilkes

Derler

et al. 2009

International Journal of Impact Engineering

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In accidents, motorcycle riders full-face helmets often make oblique impacts with road surfaces. Finite Element Analysis was used to predict the rotational and linear acceleration of a Hybrid II headform, representing a motorcyclist's head, in such impacts, considering the effects of friction at the head/helmet and helmet/road interfaces. Simulations of the oblique impact test in British Standard BS 6658 were validated by comparison with published data.This showed that COST 327 experimental data was largely determined by the friction coefficient (0.55) between the helmet shell and abrasive paper, and hardly affected by that between the head and helmet. Slip was predicted at the shell/paper interface throughout the impact, due to the high angular inertia of the helmet, and the normal force remaining below 3.5 kN. Simulations of more severe motorcycle helmet impacts explored the effects of impact site and direction, impact velocity components, helmet fit and the scalp. In these impacts, the higher velocity component normal to the road caused high frictional forces on the helmet shell, eventually causing it to roll on the road. The peak headform rotational accelerations, at some impact sites, were potentially injurious. The most effective method of reducing head rotational acceleration could be a reduction in the linear acceleration limit of the helmet standards.

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Section: Helmet Materials Propertiessupporting

confidence: 92%

FEA of oblique impact tests on a motorcycle helmet

Mills

Wilkes

Derler

et al. 2009

International Journal of Impact Engineering

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“…EPS geofoam is known to exhibit highly nonlinear mechanical behaviour and density-dependent stressstrain characteristics (e.g., Hazarika and Okuzono, 2004;Chun et al, 2004;Hazarika, 2006;Negussey, 2007). The density appears to be a useful index parameter for EPS geofoam that correlates with most of its mechanical properties such as compression strength, shear strength, tension strength, ‰exural strength, stiŠness and creep deformation.…”

Section: Eps Geofoam Specimenmentioning

confidence: 99%

“…However, from a viewpoint of soil -structure interactions, the properties of particular interest are compressive strength and modulus and long-term creep behaviour (Tsukamoto et al, 2002;Hazarika, 2006; and others).…”

Section: Introductionmentioning

confidence: 99%

Small-Strain Stress-Strain Properties of Expanded Polystyrene Geofoam

Abdelrahman

Kawabe

Tsukamoto

et al. 2008

Soils and Foundations

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The small-strain stress-strain properties of expanded polystyrene (EPS) geofoam with densities of about 20 kg/m 3 and 30 kg/m 3 were evaluated by laboratory unconˆned compression tests on specimens of 75 mm in diameter and 150 mm in height. Two series of tests were conducted, which were continuous monotonic loading (ML) tests and ML tests intervened by sustained creep loading and minute cycles of unload and reload. Relatively small vertical and horizontal strains were locally measured by means of a pair of local deformation transducers (LDTs) and a set of three clip gauges, respectively. The paramount importance of measuring local strains in compression tests on EPS to reliably evaluate its stress-strain properties, in particular those at relatively small strains, is demonstrated. The initial modulus, E0, and Poisson's ratio, n0, were evaluated from initial stress-strain relations at small strains obtained by these ML tests. The tangent parameters, Etan and ntan, were also evaluated from the ML stress-strain behaviour. The equivalent parameters, Eeq and neq, were evaluated from the stress-strain behaviour during minute cycles of unload and reload. The stress-strain behaviour is essentially linear only at small strains, and it becomes highly non-linear and a signiˆcant drop of stiŠness occurs as observed in the overall stress-strain behaviour. The Poisson's ratio for inelastic deformation is found to be negative.

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“…Both need to be investigated with respect to measuring and modeling their stress-strain characteristics so as to evaluate the field design and construction. To date, investigations regarding EPS blocks can be reached through many sources, for examples, field and laboratory measurements (Doskov 1997;Fang et al 2006), and modeling analyses (Chun et al 2004;Hazarika and Okuzono 2004;Wang et al 2006;Wong and Leo 2006;Hazarika 2006). There were also reports in the public domain about the measurements of soil-EPS-cement mixtures (Liu et al 2006;Zhu et al 2008)), whereas no implementation was reported on measuring and modeling the stress-strain behavior of soil-EPS beads mixtures.…”

Section: Introductionmentioning

confidence: 99%

Measuring and Modeling Proportion-Dependent Stress-Strain Behavior of EPS-SandMixture

Deng

Xiao

2010

Int. J. Geomech.

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A geofoam was produced by blending expanded polystyrene (EPS) beads and sands in proportions. The formed mixtures, known as EPS-sands, were 32-66% lighter than general earthfills (e.g., sand). Consolidated-drained (CD) triaxial compression tests were conducted on EPS-sand mixture specimens to observe their stress-strain characteristics, specifically, the stress-strain responses in relation to the EPS contents (0.5%, 1.5% and 2.5% by weight) used in the mixtures and confining pressures

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Stress–strain modeling of EPS geofoam for large-strain applications

Cited by 80 publications

References 11 publications

FEA of oblique impact tests on a motorcycle helmet

FEA of oblique impact tests on a motorcycle helmet

Small-Strain Stress-Strain Properties of Expanded Polystyrene Geofoam

Measuring and Modeling Proportion-Dependent Stress-Strain Behavior of EPS-SandMixture

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