Christopher J. Szczepanski

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An analysis of fatigue crack-initiation facets from the perspective of variability in lifetime of a duplex microstructure of Ti-6Al-4V is presented. Fatigue variability behavior of this alloy was marked by an increase in the lifetime variability to almost three orders in magnitude as the stress level was decreased. Crack initiation was found to occur(More)
A system for ultrasonic fatigue testing at temperatures as high as 700 C and at positive mean stresses has been developed. Its use is demonstrated by examining the fatigue behavior in the lifetime range of 10 to 10 cycles for the nickel-base superalloy Rene' 88 DT at 20 and 593 C for a load-ratio of 0.05. Crack initiation occurred from large grains and from(More)
The work presents quantitative relations between service-dependent noise dose levels and "unspecific" for the noise influence remote effects basing on the study of the cardiovascular system of 207 members of the deck and engine room crews. The seamen observed had no hearing losses due to noise (according to the ISO standard 1999). The study carried out in(More)