平均ねじり応力を付与可能な超音波ねじり疲労試験機の開発

抄録

It is thought that torsional fatigue strength is not affected by mean torsional stress. However, a few researchers has recently reported that torsional fatigue strength in the very high cycle region of spring steels having shot peening decreased with increasing mean torsional stress. In order to examine the phenomena, an accelerated torsional fatigue testing machine that allows us to apply mean torsional stress is required. In this study, we have developed an ultrasonic torsional fatigue testing machine subject to mean torsional stress of 300 MPa or higher.