J. Wayne Jones

Professor Emeritus

jonesjwa@umich.edu

2022 Gerstacker

T: (734) 764-7503

Bio

Projects

Publications

Facilities

Group


GOALI: Investigation by Ultrasonic Methods of the Very Long Life Fatigue Behavior of Structural Aluminum and Magnesium Alloys

Sponsor: National Science Foundation-Division of Materials Research
The objectives of this research are to investigate the very long life (107 to 109 cycles) fatigue behavior of cast aluminum and magnesium structural alloys and to develop accurate models of crack initiation and short crack propagation behavior that can be used for predicting fatigue life. Cast aluminum and magnesium alloys are being investigated because they represent a commercially important group of lightweight alloys. Very long lifetimes will are achieved in a practical timeframe using ultrasonic fatigue in which cyclic loading is applied at frequencies of approximately 20 kHz. The dependence of fatigue crack initiation behavior and the growth of small fatigue cracks is being investigated for a range of microstructures and defect sizes. At lifetimes >108, endurance limits have been observed in recent studies in cast aluminum and magnesium alloys. The current program examines the fundamental mechanisms responsible for the presence or absence of endurance limits in this important set of alloys. The observed initiation and propagation behavior are then incorporated into life prediction methodologies for the very long life regime. A significant effort is focused on the potential use of ultrasonic fatigue techniques as a viable alternative or replacement for more conventional testing methods, especially where critical fatigue lives are in the very long life regime.