On the variation of fatigue-crack-opening load with measurement location

摘要: The work presented here evaluates the validity of using load at point linearity on displacement curve, as suggested by Elber, an experimental measure crack-tip-opening Displacement-load behavior was investigated for a fatigue-cracked modified compact specimen nickel-base superalloy. Displacements were determined notch mouth standard clip-on gage, along crack sufrace laser-interferometric gage and, in plastic zone ahead crack, optical- interferometry technique. Acoustic-emission monitoring employed means to detect potential extension during measurement-load cycles and physical- closure. magnitude from these measurements, is dependent distance tip which measurement made. As additional evaluating load, crack-surface profiles are constructed displacement- measurements made behind tip. A discussion given concerning significance results toad para- meter quantify