This thesis reports on a design study, conducted for an advanced composite helmet shell for helicopter pilots. The helmet shell is expected to provide a level of protection against low velocity impacts with its weight criteria. Therefore, ergonomy, light weight, and the ability to withstand low velocity impact became the main issues for this study. For this purpose, an experimental program has been developed including low velocity impact tests on specimens. The drop height, drop weight, specimen stacking sequences and size were constant parameters. Test specimens were produced using the plate size of 220x220 mm having different thicknesses. Specimen materials were aramid, carbon, and a hybrid form of these two. Thus, the parameters of the study were specimen thickness and the material types.
The impact tests are carried out on a specially designed test rig. The design decisions are made in accordance with the results of the experiments. In compliance with the lightweight and manufacturing criteria, the hybrid specimen was selected helmet shell.
For the purpose of ergonomy a geometric design was also conducted from headfrom sizes of Turkish Army by using 3D design software. After specifying the composite material, manufactured helmet shell was tested in another test rig according to the ANSI Z90.1.1992. For the requirement of the acceleration level 300g, the helmet shell design was found to be successful at seven different and critical impact points.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12614053/index.pdf |
| Date | 01 February 2012 |
| Creators | Sunel, Ezgi |
| Contributors | Parnas, Levend |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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