NASA TECHNICAL NOTE NASA - TJ D: 2. / -_y_ 5340 A SEMIEMPIRICAL FRACTURE ANALYSIS FOR SMALL SURFACE CRACKS by Thomas We Orange Lewis Research Center Cleveland, Ohio NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. JULY 1969 brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by NASA Technical Reports Server