Lecturer, Cambridge University Engineering Department,
Pages: 16 Published: Jan 1983
Short fatigue cracks are the linkage of the initiation stage to the long crack growth which can be described by linear elastic fracture mechanics. Because some cracks can initiate then cease to grow, short cracks are important in the definition of fatigue limits. This paper reviews the fatigue limits of plain and notched components and concludes that this particular short crack problem can be overcome by macroengineering parameters. So far as the growth of short cracks is concerned, their interaction with microscopic metallurgical features can be treated quantitatively only in a local sense. However, their growth in large plastic strain regions, which typically occur at a notch root, can be described by semiempirical macromechanics parameters. Finally, it is shown that in many practical circumstances the bulk of the fatigue life can be considered to be either initiation or long crack propagation, thus bypassing the short crack problem.
crack size, long crack growth, short crack growth, crack initiation, slip bands, linear elastic fracture mechanics, elastic-plastic fracture mechanics, notches, plain fatigue limits, crack growth threshold, notch plasticity, crack tip plasticity
Paper ID: STP30561S