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).
Stress-strain diagrams, the effects of cold working, and torque analysis in shafts.
| Identifier | ExFiles\Box 170\3\ img004 | |
| Date | 4th December 1935 | |
| (Sheet 2) On the other hand if cold-working had no effect one would expect that since the first settling was 3.8 degrees, the second would be 7.6 degrees. So apparently both effects are present. (5) Suppose that for the sake of argument one assumes that cold working has no effect in raising the elastic limit, then the stress-strain diagram will be thus:- [DIAGRAM] ELASTIC LIMIT - SAY 100,000 STRESS STRAIN ACTUAL LINE COLD WORKING EFFECT STRESS-STRAIN DIAGRAM ASSUMED FOR FURTHER FIGURING You will say that this is not an actual stress-strain diagram, but my reply would be that it is at least a good enough approximation to form a basis for further argument. Also the actual rise of the diagram above the elastic limit is probably a measure of cold-working effects which we are trying to isolate. (You will see what I am getting at if you will read a little further. I am arguing that in figuring stresses in coil springs etc. we have been exercising the engineers' prerogative of kidding ourselves all to hell). (6) Suppose we accept the horizontal line on the stress-strain diagram as a working hypothesis, what will it do to the rod when stressed beyond the elastic limit. [DIAGRAM] B A C We normally assume a stress-diagram like "A", a force diagram like "B", and a torque diagram like "C". The area of "C" is the torque in the shaft. This is probably true up to the elastic limit. | ||