High frequency method for determining the non-propagation threshold of fatigue cracks

摘要

How to determine the non-expansion threshold for fatigue cracks at high frequencies, where repeated loads 32 and 32A are applied to at least one test piece having an elliptical hole 12 in the test zone 10A, and the elliptical hole is one side Two rigid frees with notches 14 at the ends, the test pieces arranged on both sides of the at least one test piece and fastened to the two rigid masses at their two ends 20A, 22A; 20B, 22B, respectively. -Stress plates (20, 22; 60, 62) held between two rigid masses (24, 26: 56, 58), comprising test specimens, masses, and stress plates to generate fatigue cracks from the notches Repeated loading occurs at a frequency selected to be equal to the resonance frequency of the assembly, and once it is observed that the crack has stopped expanding, the final length of the crack is measured, and the chart shows the threshold for non-expansion of fatigue crack (Δ). K