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).
Experimental department report on the fatigue failure examination of an engine crankshaft.
| Identifier | ExFiles\Box 10\3\ 03-page216 | |
| Date | 24th August 1929 | |
| EXPERIMENTAL DEPARTMENT REPORT ON EXAMINATION OF CRANKSHAFT. On taking down the Engine after its 50 hours run, the crankshaft was found to be cracked at the fillet radius of No. 6 Crankpin. The fracture was for about two-thirds of the circumference, and was more open on the side nearer the web. The crankshaft was sectioned through the line of the fracture and one half prepared for microscopic examination. The other half was broken through the crack, and the fractured surface examined. MICROSCOPIC. Examination showed that the material was clean and free from inclusions. The structure was sorbitic, and quite normal for this class of material. FRACTURE. The fracture was of the fatigue type, starting from the outside and spreading inwards. The surface of the break showed a series of concentric rings, having for their centre a point on the periphery. CONCLUSION. The failure was due to fatigue, and not to any defect in the material. The point of origin of the fracture was on the surface of the fillet radius. | ||