The application of displacement and energy approaches to the determination of stress intensity factors in ultrasonic fatigue crack growth (fcg) studies is discussed.The particular advantages as well as the limitations...The application of displacement and energy approaches to the determination of stress intensity factors in ultrasonic fatigue crack growth (fcg) studies is discussed.The particular advantages as well as the limitations of the two approaches are evaluated.Two types of ultrasonic fatigue loading with different stress ratios are exerted on the specimen respectively: the ultrasonic fatigue loading with a stress ratio R=-1 and the ultrasonic fatigue excitations superposed upon a static mean stress with R>-1 From comparison the conclusion is formed that the energy approach developed in the investigation is more accurate,concise and suitable than commonly adopted approaches and/or formulas proposed.Experimental fcg data on a titanium alloy Ti-6Al-4V and the characteristic mechanism of the ultrasonic fcg are investigated.展开更多
文摘The application of displacement and energy approaches to the determination of stress intensity factors in ultrasonic fatigue crack growth (fcg) studies is discussed.The particular advantages as well as the limitations of the two approaches are evaluated.Two types of ultrasonic fatigue loading with different stress ratios are exerted on the specimen respectively: the ultrasonic fatigue loading with a stress ratio R=-1 and the ultrasonic fatigue excitations superposed upon a static mean stress with R>-1 From comparison the conclusion is formed that the energy approach developed in the investigation is more accurate,concise and suitable than commonly adopted approaches and/or formulas proposed.Experimental fcg data on a titanium alloy Ti-6Al-4V and the characteristic mechanism of the ultrasonic fcg are investigated.
