Participant: PROMISE AGEP Research Symposium, 2014
Alexander D. Smith
Department: Mechanical Engineering Department
Institution: University of Maryland, Baltimore County (UMBC)
Extending the Fatigue Life of Service Components
The most common type of failure or fracture of engineered components is fatigue. Fatigue fractures occur from cyclic stresses, or the repetitive loading and unloading of the component. These types of fractures are particularly hazardous because they can occur under normal service conditions and with no warning. Thus, there is a significant interest into methods to extending the service / fatigue life of engineered components.
One of these methods is to introduce an overload into the system. These overloads have been shown to retard crack growth under constant amplitude cyclic loading conditions which are under the overload stress value. New studies are observing the effect of multiple overloads at varying amplitudes and their effect on the fatigue life of components. These results will then be used to develop a behavioral model and compared to the benefit of singular overloads.
Alexander Smith earned his Bachelor of Science degree in Mechanical Engineering from the University of Maryland Baltimore County in 2011. He is currently a second year graduate student at the University of Maryland Baltimore County continuing his studies in Mechanical Engineering.
Mr. Smith has been the recipient of numerous honors and awards including the Louis Stokes for Minority Participation Bridge to Doctorate Fellowship. He was also awarded with the Meyerhoff Scholarship.
While he was pursuing these degrees, Mr. Smith conducted research as an intern at the Army Research Laboratory in Aberdeen Maryland in 2009 and 2010. He also interned at Technology Assessment and Transfer Inc. in 2011 and was a full time staff member before returning to UMBC for his graduate studies.
Mr. Smith is currently conducting research under the supervision of Dr. Ahktar Khan on the effect of multiple overloads at varying amplitudes on the fatigue life of aluminum alloys and consequently modeling this behavior.
GENERAL SUMMARY OF GRADUATE RESEARCH
Alexander Smith is currently conducting research at the University of Maryland Baltimore County under the supervision of Dr. Ahktar Khan in the mechanical engineering department. The focus of this research is to model and explain the crack retardation phenomenon that follows an overload. The fatigue life has been known to increase due to a single overload in a fatigue cycle. This research has examined the effect of multiple overload cycles at varying stress amplitudes in multiple aluminum 6061 and aluminum 7075 alloy specimens. These fatigue testing results have shown a correlation to the amount of retardation and the overload stress magnitude when compared to the constant amplitude operating stress.
Future work will consist of modifying existing behavioral models to reflect and predict the experimental data for both aluminum 6061 and aluminum 7075 specimens.
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