Wpływ przeciążeń na wzrost szczelin zmęczeniowych

Fatigue crack growth behavior was investigated in nine quite different metals under various overload conditions. Single, multiple and intermittent tensile overloads along with single compressive overloads were applied principally to compact tension specimens. Constant amplitude testing following overloads was applied with stress ratios R ranging from 0 to 2. Single edge notch specimens were also tested to verify compression influence in the compact tension specimens and to measure crack closure. A simplified model was developed to predict fatigue crack growth under intermittent tensile overloads based upon constant amplitude fatigue crack growth behavior, retardation, reversed plane stress plastic zone sizes and fracture toughness. The paper is a review of six years of research at the University of Iowa concerning fatigue crack growth interaction effects.