24-10-2012, 02:18 PM
Mechanical Data for Use in Damage Tolerance Analyses
ABSTRACT
This report describes the results of a research program to determine the damage tolerance properties of metallic propeller
materials. Three alloys were selected for investigation: 2025-T6 Aluminum, D6AC Steel and 4340 Steel. Mechanical response,
fatigue (S-N) and fatigue crack growth rate data are presented for all of the alloys. The main conclusions that can be drawn
from this study are as follows. The damage tolerant design of a propeller system will require a complete understanding of the
fatigue crack growth threshold. There exists no experimental procedure to reliably develop the fatigue crack growth threshold
data that is needed for damage tolerant design methods. Significant research will be required to fully understand the fatigue
crack growth threshold. The development of alternative precracking methods, evaluating the effect of specimen configuration
and attempting to identify micromechanical issues are simply the first steps to understanding the mechanics of the threshold.
ABSTRACT
This report describes the results of a research program to determine the damage tolerance properties of metallic propeller
materials. Three alloys were selected for investigation: 2025-T6 Aluminum, D6AC Steel and 4340 Steel. Mechanical response,
fatigue (S-N) and fatigue crack growth rate data are presented for all of the alloys. The main conclusions that can be drawn
from this study are as follows. The damage tolerant design of a propeller system will require a complete understanding of the
fatigue crack growth threshold. There exists no experimental procedure to reliably develop the fatigue crack growth threshold
data that is needed for damage tolerant design methods. Significant research will be required to fully understand the fatigue
crack growth threshold. The development of alternative precracking methods, evaluating the effect of specimen configuration
and attempting to identify micromechanical issues are simply the first steps to understanding the mechanics of the threshold.