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Abstract:
The primary tasks addressed were: (1) The design and development of durable hub-to-rotor attachments and the balancing and vibrational analysis of the resulting hub-rotor systems; (2) Measuring and analyzing the strength distributions and durabilities of different types of plywood and of hub-rotor systems. In accomplishing these tasks, a new metallic-hub to cellulosic rotor bonding attachment was designed which utilizes a flexible scalloped metal-band in lieu of the traditional elastomeric layers to accommodate the differential strain between rotor and hub. With the objective of eliminating the need for adding or removing mass to balance rotors, a self-centering dynamic balancer was designed to automatically locate the inertial axis of a rotor. Attaching the hubs and shafts concentric and parallel with the inertial axis will accomplish the balancing of the rotor during assembly. In analyzing rotor vibrations, a nondimensional design parameter was derived which correlates the support flexibility required to the useable strength and length of the rotor for a useful operating range above the transverse critical frequency. The tensile strengths of conventional Finnish birch plywood were measured in three directions using material equilibrated at 50% relative humidity and vacuum-dried material. Similar measurements of custom-made, hexagonal, yellow birch plywood showed double the mid-ply strengths. The standard deviation of the measured strengths and the drop in mean strength with vacuum drying were both on the order of 10%. High resolution (0.01%) microprocessor data acquisition equipment was assembled to monitor tensile tests.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Final rept. |
| Pages: |
106 |
| Report Date: |
FEB 80 |
| Contract Number: |
DE-AC04-76DP00789 |
| Report Number: |
A023103 |
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