SEDL / STP / STP982-EB / STP27233S

Influence of Fatigue Crack Wake Length and State of Stress on Crack Closure

Telesman, J
Materials engineers, NASA Lewis Research Center, Cleveland, OH

Fisher, DM
Materials engineers, NASA Lewis Research Center, Cleveland, OH

Pages: 15    Published: Jan 1988

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Abstract

The location of crack closure with respect to crack wake and specimen thickness under different loading conditions was determined. The rate of increase of K^CL in the crack wake was found to be significantly higher for plasticity induced closure in comparison to roughness induced closure. Roughness induced closure was uniform throughout the thickness of the specimen while plasticity induced closure levels were 50% higher in the near surface region than in the mid-thickness. The influence of state of stress on low-high load interaction effects was also examined. Load interaction effects differed depending upon the state of stress and were explained in terms of ΔK^eff.