From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Investigation into the effect of stress range and plate thickness on the durability of road springs.
| Identifier | ExFiles\Box 72\3\ scan0128 | |
| Date | 5th September 1924 | |
| X. 9410 To BY.{R.W. Bailey - Chief Engineer} & HS.{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} S E C R E T. DA{Bernard Day - Chassis Design}2/M/5.9.24. E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. RE. ROAD SPRINGS. X. 9410. We suggest that it would be useful information to investigate the effect of range of stress in the spring plates. We believe that you can comparatively easily do this, for instance, we suggest that the specimen might consist of a diamond shaped flat plate of varying thicknesses, supported at the diamond points and loaded in the centre by a fluctuating load such as is produced for instance by a crank and connecting rod. The stroke might be capable of being varied. From Mr. Hives report of the superior durability of the Woodhead springs with the .285 thickness of top plate we are inclined to conclude that the range of stress may have something to do with it. The point that appears to us to be interesting is the relation between the range of stress and the height on the stress scale at which this range takes place. In springs we have recently used, that is to say, with the .312 top plates, though the top plate in any one case goes through a greater range than the lower plates, it does so apparently at a lower height on the scale. Is it possible that in spite of this, on account of the greater range, it still has a greater tendency to fail? In the springs that have broken we wonder whether any attempt has been made to micrometer the top plates. There is a toleration given on the spring drawing of from .285 to .312. It may be that the top plates that have broken are therefore of varying thickness, and it would be information immediately available if there were any relation between the actual thickness and the life of the top plates that have broken. DA.{Bernard Day - Chassis Design} | ||