Theoretical Prediction of Ripple-Load Effect on Stress-Corrosion Cracking

Abstract

The ripple-load effect (RLE) is a perplexing phenomenon in which the threshold stress-intensity factor (KIscc) for stress-corrosion cracking (SCC) appears to be severely degraded -- at least in some cases, if the constant load condition characteristic of SCC is perturbed by superposition of a small-amplitude cyclic load. In this study, a theoretical framework has been developed to predict the conditions required for a material to exhibit a RLE in a marine environment -- and the extent of such degradation. Insofar as a framework for the RLE necessarily involves the interface between SCC and corrosion fatigue (CF), the model presented herein derives from concepts and descriptors used in SCC and CF characterization. Thus, analysis begins with consideration of the relationship between the small amplitude stress-intensity range associated with ripple loading, delta K, the high stress-ratio conditions, R > 0.90, the threshold for CF crack growth, delta Kth, the maximum stress-intensity factor in the loading cycle, Kmax, and KIscc. Keywords: Stress-corrosion cracking, Corrosion fatigue, Ripple-load cracking, High stress ratio.

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Document Details

Document Type
Technical Report
Publication Date
May 31, 1988
Accession Number
ADA196348

Entities

People

  • George R. Yoder
  • Peter S. Pao
  • R. A. Bayles

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Amplitude
  • Corrosion
  • Crack Tips
  • Cracks
  • Cyclic Loads
  • Environment
  • Geometry
  • Intensity
  • Materials
  • Materials Science
  • Mechanics
  • Military Research
  • Resistance
  • Stress Corrosion
  • Stress Corrosion Cracking
  • Stress Intensity Factors
  • Test Methods

Readers

  • Materials Science (Mechanical Engineering).
  • Materials Science and Engineering.
  • Theoretical Analysis.