Industrial helmet performance in impacts

Mills, N. J.; Gilchrist, A.

doi:10.1016/0925-7535(93)90045-f

Cited by 17 publications

(9 citation statements)

References 6 publications

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“…In our case, the gas is air at atmospheric pressure, for which the conductivity at room temperature is air ϭ 0.0263 W/m K. The gas in the cells is air, because gases can diffuse in and out of LDPE foams on a time scale of weeks. 24,25 The second term in eq 3 is associated with the contribution of the solid phase. From the DSC results, we concluded that the solid polymer in the cell walls of the foams had similar characteristics compared to a solid sheet produced from the same polymer.…”

Section: Conduction Through the Solid And Gas Phasesmentioning

confidence: 99%

Prediction of the radiation term in the thermal conductivity of crosslinked closed cell polyolefin foams

Almanza

Rodríguez‐Pérez

Saja

2000

J. Polym. Sci. B Polym. Phys.

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Section: Conduction Through the Solid And Gas Phasesmentioning

confidence: 99%

Prediction of the radiation term in the thermal conductivity of crosslinked closed cell polyolefin foams

Almanza

Rodríguez‐Pérez

Saja

2000

J. Polym. Sci. B Polym. Phys.

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“…In our case, the gas is air at atmospheric pressure for which the conductivity at 24, 30, 40 and 50°C has been taken as 0.0257, 0.0262, 0.0269 and 0.0277 (21) . The gas in the cells is air, since gases such as nitrogen and air can diffuse in and out of LDPE foams and achieve equilibrium on a time scale of weeks (22) .…”

Section: Thermal Conductivitymentioning

confidence: 99%

The Effect of Cell Size on the Physical Properties of Crosslinked Closed Cell Polyethylene Foams Produced by a High Pressure Nitrogen Solution Process

Rodríguez‐Pérez

González-Peña

Witten³

et al. 2002

Cellular Polymers

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The thermal conductivity, thermal expansion, mechanical properties at low strain rates and dynamic mechanical properties of a collection of crosslinked closed cell polyethylene foams manufactured by a high pressure nitrogen solution process have been studied as a function of the cell size. The main mechanisms that influence each property and the foam microstructure have been considered to rationalise the results. A theoretical model has been used to examine the thermal conductivity values. The results have shown the extent to which reducing the cell size could improve the insulating capabilities of these materials. The effect of cell size on the mechanical properties at low strain rates is very small, as a consequence the thermal expansion does not depend on cell size. Nevertheless, the structural characteristics are seen to influence dynamic mechanical response at temperatures below 15°C.

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“…The helmets used by construction site workers 18,19 are mainly designed for protection from objects, usually with a larger mass, that are dropped on the top of helmet in a vertical direction. 20 Ballistic helmets are mainly used for the protection from object impact or penetration, where the object has a smaller mass and impacts with the front of the helmet.…”

Section: Introductionmentioning

confidence: 99%

Finite element simulations of the head–brain responses to the top impacts of a construction helmet: Effects of the neck and body mass

Pan

Wimer

et al. 2016

Proc Inst Mech Eng H

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Traumatic brain injuries are among the most common severely disabling injuries in the United States. Construction helmets are considered essential personal protective equipment for reducing traumatic brain injury risks at work sites. In this study, we proposed a practical finite element modeling approach that would be suitable for engineers to optimize construction helmet design. The finite element model includes all essential anatomical structures of a human head (i.e. skin, scalp, skull, cerebrospinal fluid, brain, medulla, spinal cord, cervical vertebrae, and discs) and all major engineering components of a construction helmet (i.e. shell and suspension system). The head finite element model has been calibrated using the experimental data in the literature. It is technically difficult to precisely account for the effects of the neck and body mass on the dynamic responses, because the finite element model does not include the entire human body. An approximation approach has been developed to account for the effects of the neck and body mass on the dynamic responses of the head–brain. Using the proposed model, we have calculated the responses of the head–brain during a top impact when wearing a construction helmet. The proposed modeling approach would provide a tool to improve the helmet design on a biomechanical basis.

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Industrial helmet performance in impacts

Cited by 17 publications

References 6 publications

Prediction of the radiation term in the thermal conductivity of crosslinked closed cell polyolefin foams

Prediction of the radiation term in the thermal conductivity of crosslinked closed cell polyolefin foams

The Effect of Cell Size on the Physical Properties of Crosslinked Closed Cell Polyethylene Foams Produced by a High Pressure Nitrogen Solution Process

Finite element simulations of the head–brain responses to the top impacts of a construction helmet: Effects of the neck and body mass

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