A Newly Developed Multi-Harmonic Rotating Beam Fatigue Testing Machine

Abstract

A new fatigue testing machine was developed for the purpose of reproducing the same load conditions as those generally experienced by the rotating shafts of the machine under service conditions. In this machine used for the experiment the rotating specimen was primarily loaded by the constant weight as in the machine of cantilever beam type, and was secondarily loaded by the vibrator, which was driven by the out-put current of the generator or by another A. C. power, and generated the vibration of constant amplitude with certain frequency. The results were that each point of the circumference of the specimen received in general different multi-harmonic stress. But for certain combination of the frequency of the vibrator and the rotating speed of the specimen, it was possible for every point on the circumference to receive approximately the same multi-harmonic stress. The performance of the machine was found to be quite satisfactory through the tests.