Palmgren-Miner Theory 41 Corten-Dolan Theory Equivalent-Crack-Length Theory Relation Between Broad-Band and Narrow-Band Loading Comparison with Fuller's test results CONCLUSIONS 67 RECOMMENDATIONS FOR FURTHER STUDY 69 LITERATURE CITED ACKNOWLEDGMENTS APPENDIX 76 »00 Evaluation of z^W(z}dz. 0 Narrow-band loading 76 Broad-band random loading 76 Op stress peak in random loading, ksi a root mean square value of instantaneous stress, ksi rms 0} angular frequency, rad/sec.