Effect of Shear Lips, Loading Transitions and Test Frequency on Constant Delta K and Constant Load Amplitude Fatigue Tests

摘要

The scope of this thesis is: to ivestigate the fatigue crack growth behavior of several materials during constant load amplitude and constant DeltaK type fatigue tests; to look at the basic parameters that control the crack growth rate in these materials; and to study the presence or absence of shear lip development in these materials. Chapter 1 contains a review of the literature regarding fatigue crack growth. Chapters 2, 3, and 4 deal with experimental technique, crack tip plasticity and reproducibility of test results respectively. Chapters 5 and 6 deal with the results obtained on materials that did not form shear lips. Chapter 7 will deal with the basics of shear lip development and with the effect of shear lips. Chapters 8 and 9 will deal with the results obtained on materials that do form shear lips. Chapter 10 will deal with the problem of frequency effects on shear lip development. The final chapter compares and discusses the results obtained on different materials.