A Suggested Method of Increasing the Damping of Aircraft Structures
Abstract
The object of this work is to find means of increasing damping in the joints of a structure, similar to a riveted structure by the use of plastic inserts in the joints. Information on the effect of pressure cabin sealing and the adoption of spot-welded or Redux (a means of joining metal plates by the insertion of thermo-plastic, which is fused by the application of heat and pressure) welding construction is also given. This report discusses the operation of an insert, the properties called for in service and recommends four suitable materials for further tests. The apparatus used to compare the damping of inserts made from a number of different materials is described. The effect of thickness of insert on damping has been investigated and the variation of damping with temperature has been obtained between -25 and +25 deg C for the material Poly-iso-butelene. These investigations show how, by means of an insert of Poly-iso-butelene, it is possible to increase the damping of a riveted structure. For vibration at a frequency of 36 cycles per second the tamping is increased 200% for a maximum dynamic stress in the test specimen of 70 lb/sq in. For stresses higher than this but within the elastic range of the structure a larger increase in damping may reasonably be expected.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1946
- Accession Number
- ADB184088
Entities
People
- D. H. Cooper
Organizations
- Royal Aircraft Establishment