Deformation mechanisms and impact attenuation characteristics of thin-walled collapsible air chambers used in head protection
| Autor: | T B Hoshizaki, L Lamb |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Absorption (acoustics)
Materials science business.industry Air Mechanical Engineering Drop (liquid) Acceleration Airflow Poison control Equipment Design General Medicine Structural engineering Volumetric flow rate Equipment Failure Analysis Energy Transfer Hardness Elastic Modulus Physical Stimulation Head (vessel) Head Protective Devices Stress Mechanical Composite material Impact business Body orifice |
| Zdroj: | Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. 223:1021-1031 |
| ISSN: | 2041-3033 0954-4119 |
| Popis: | Head injuries are a major cause of morbidity and mortality worldwide, many resulting from sporting activities. There is a constant need in the head protection industry for improved methods to manage impacts and to reduce the risk of mild and severe head injuries. Contemporary head protection primarily consists of foam with several inherent disadvantages, including a limited ability to provide effective energy absorption under both low and high impact velocities. Recently, thin-walled collapsible chambers were engineered to address this problem and have been implemented into sport helmets. The chambers consist of four engineering elements which define their dynamic performance: geometry, air volume, material, and venting system. This research analysed the contribution of air flow through an orifice to the chamber's management of impact energy. The objective of this study was to determine the effect of the chamber's vent diameter and material stiffness on peak force and venting rate during an impact. Two material stiffnesses (thermoplastic polyurethane 45D and thermoplastic polyurethane 90A) and five vent diameters (1 mm, 2 mm, 3 mm, 4 mm, and 5 mm) were tested at three inbound velocities (1.3 m/s, 2.3 m/s, and 3.0 m/s). Each chamber was impacted ten times using a monorail drop system. Analysis of the results revealed that the material stiffness, vent diameter, and inbound velocity all had a significant effect on peak force and venting rate ( p |
| Databáze: | OpenAIRE |
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