Download or read book The Detection of Fatigue Cracks by Nondestructive Testing Methods written by Ward D. Rummel and published by . This book was released on 1974 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-RADIOGRAPHIC, PENETRANT, ULTRASONIC, EDDY CURRENT, HOLOGRAPHIC, AND ACOUSTIC EMISSION TECHNIQUES WERE OPTIMIZED AND APPLIED TO THE EVALUATION OF 2219-T87 ALUMINUM ALLOY TEST SPECIMENS. ONE HUNDRED EIGHTEEN SPECIMENS CONTAINING A TOTAL OF 328 FATIGUE CRACKS WERE EVALUATED. THE CRACKS RANGED IN LENGTH FROM 0.500 INCH (1.27 CM) TO 0.007 INCH (0.018 CM) AND IN DEPTH FROM 0.178 INCH (0.451 CM) AND 0.001 INCH (0.003 CM). SPECIMEN THICKNESSES WERE NOMINALLY 0.060 INCH (0.152 CM) AND 0.210 INCH (0.532 CM) AND SURFACE FINISHES WERE NOMINALLY 32 AND 125 RMS AND 64 AND 200 RMS RESPECTIVELY. SPECIMENS WERE EVALUATED IN THE 'AS-MILLED' SURFACE CONDITION, IN THE CHEMICALLY MILLED SURFACE CONDITION AND, AFTER PROOF LOADING, IN A RANDOMIZED INSPECTION SEQUENCE. RESULTS OF THE NONDESTRUCTIVE TEST (NDT) EVALUATIONS WERE COMPARED WITH ACTUAL CRACK SIZE OBTAINED BY MEASUREMENT OF THE FRACTURED SPECIMENS. INSPECTION DATA WERE THEN ANALYZED TO PROVIDE A STATISTICAL BASIS FOR DETERMINING THE THRESHOLD CRACK DETECTION SENSITIVITY (THE LARGEST CRACK SIZE THAT WOULD BE MISSED) FOR EACH OF THE INSPECTION TECHNIQUES AT A 95% PROBABILITY AND 95% CONFIDENCE LEVEL.