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).
Technical analysis of the frequency of vibration in spiral springs, specifically in relation to valve spring breakages.
| Identifier | ExFiles\Box 56\2\ Scan096 | |
| Date | 28th August 1930 guessed | |
| -2- where E is the elasticity or rate of the whole spring, namely the load in poundals per foot of compression and M is the mass of the whole spring in pounds. The more immediately useful rearrangement of this expression for the frequency of vibration of a spiral spring is n = (d / 8πkD²) * √(2Cg / w) (approximately) As there appears good ground for supposing that valve spring breakages occur as a result of dynamic stresses caused by oscillations of the spring coils, it is generally agreed to be desirable that the natural frequency of vibration of the spring shall be as high as possible consistent with the usual static quantities being as desired. It is of interest to examine what direction is indicated by the use of the above results in which to vary the design of the spring to keep the natural frequency of vibration as high as possible. Omitting the invariable portion of the expression for the frequency above given (i.e. C shear modulus, g gravity and w density of wire) it is seen that the frequency number of vibration of a spiral spring varies as d / kD² It is also seen from the statical results given that the ratio of the stress to the deflection | ||