This publication is a sequel to the ATSB report CR193, "The development of a protective headband for car occupants" (Anderson et al., 2000). In that report, we documented a series of tests of different energy absorbing materials, to ascertain the potential benefit of a protective headband worn by car occupants. The project was initiated after McLean et al. (1997) demonstrated that energy absorbing headwear for car occupants might be effective in reducing the numbers of head injuries sustained by car occupants. McLean et al. estimated that the benefits were greater than the estimated benefits of padding of the upper interior of vehicles to the requirements of the US Federal Motor Vehicle Safety Standard 201.
The testing reported on here extends the work reported in CR193 by investigating the suitability of materials that, on the whole, are more efficient in absorbing energy than those tested in CR193. CR193 did not consider the form that the headband might take in a production version. This is also addressed in this report with a chapter on the development of a design concept that would be feasible to manufacture and deliver to market.
CR193 identified two energy absorbing materials for further investigation; polyurethane foam and a cardboard honeycomb liner encased in a hard shell. Both these materials significantly reduced the severity of impacts with a typical car structure. The characteristics of these materials were used as a guide in the further selection of materials for testing. As the durability of cardboard in such an application may render it unsuitable, a more durable substitute was identified that retained the characteristics of high energy absorbing efficiency. The material, STRANDFOAM* (Dow Corporation) is an extruded expanded polypropylene (EPP), and has an intrinsic honeycomb structure, similar to the one in the cardboard honeycomb that gave it its exemplary energy absorbing characteristics. The third material tested was normal EPP, chosen because of its increasing use in impact energy management applications. The performance of the normal EPP also is a useful benchmark alongside which the performance of the STRANDFOAM* can be compared.
As in the tests reported on in CR193, the new tests demonstrate that a headband for car occupants could significantly reduce the severity of certain head impacts in a crash. None of the new materials improved on the energy absorbing performance of the cardboard honeycomb, although the performance of the new materials, and STRANDFOAM* in particular, certainly came close. Any of the materials tested for this report would be suitable as the energy absorbing component in the construction of the headband. The use of one or another of the materials would depend on cost, durability, ease of manufacture, and availability. While these factors have not been explicitly addressed in the report, the design development process has delivered a concept likely to be compatible with any of the materials examined herein. The design considers styling aspects relevant to its acceptability, without compromising the essential protective nature of the device.
Type: Research and Analysis Report
Sub Type: Consultant Report
Author(s): RWG Anderson, G Ponte, AJ McLean, R Tiller & S Hill
Topics: Head, Occ protection
Publication Date: 01/06/01