EVALUATION OF THERMOPLASTIC MATRIX COMPOSITES FOR USE IN ENERGY-ABSORBING HELICOPTER SUBFLOORS

The primary objective of the research conducted was to evaluate fiber-reinforced thermoplastic matrix composites for potential application in energy-absorbing helicopter subfloors. Two key elements of this study were to evaluate the energy absorption characteristics of candidate thermoplastic materials, and to evaluate five keel beam design concepts for use with a thermoplastic composite. Three fiber-reinforced thermoplastic matrix composites were investigated tor energy absorption performance. Because this paper will appear in open literature, and much of the data is subject to export control laws, the names and types of the materials evaluated will not be disclosed. They will be referred to as fiber-reinforced thermoplastic matrix Systems A, B, and C. If any of the readers have a need for the identification of the materials, they may contact the author on an individual basis to obtain them. Static and dynamic crush testing of tubes was conducted on the three thermoplastic material candidates and a baseline fiber-reinforced thermoset matrix composite. Thermoplastic System C was identified to have the best energy-absorbing performance based on these tests. The sine wave keel beam concept was selected as the best design for use with thermoplastic composites. These results will be used to continue the development of thermoplastic matrix composite energy-absorbing helicopter subfloors.