Abstract
On the strength of crankshaft many investigations have been carried out, but there are very many unknowns which have not yet been elucidated.
The author has investigated and previously reported on the strength of crankshaft, and in this report he describes on the crankshaft fillet stresses obtained by the measurements for many engines in service condition, and compares the measured stresses for the ones calculated by his method.
The results are as follow,
1. On solid forged crankshafts, axial vibration of crankshaft is hardly measured. Measured stress diagrams on these crankshaft fillets accord fairly well with calculated ones.
2. When the crankshaht fillet stress is computed, the effect of resilience of supporting bearing is not to be neglected, especially for two stroke cycle engine.
3. The mode curve of axial vibration obtained by measurement agrees fairly well with the one calculated by neglecting damping effects.
4. At resonance point of torsional vibration and its vicinity, the bending stress was observed at almost all of crankshafts fillets. But the amplitude of this bending stress does not always become its maximum at the fillet which is expected from the mode curve of torsional vibration.
Moreover the author appointed that several problems, for instance, computation of amplitude and phase of additional stress by forced vibration, more precise estimation of resilience of journal supports or of fatigue strength from ultimate tensile strength, must be investigated in future.
