Calibration of a Pulsed Potential Crack Monitor for Use in Fatigue Crack Growth Studies
ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)
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Accurate measurement of crack length is a necessary criterion for detailed analysis of the fatigue or fracture toughness performance of a material. Several methods exist but one of the most versatile uses the phenomenon of potential drop. A pulsed direct current is used to generate a potential drop as a function of crack length. Experimental values of potential drop and crack length have been obtained for three test-piece geometries a centre crack specimen, a holed specimen AGARD, and a compact tension specimen. Computed values have been generated using a Fortran program and are compared with the experimental results. Comments are made on the accuracy of the technique and its consequences on potential probe positioning for both short and long cracks. Great Britain.
- Test Facilities, Equipment and Methods