scope:

This is a detailed final report on a series of investigations made to determine a basis for the evaluation of the ability of weld flaws to initiate brittle fracture. The report is in four parts dealing successfully with (1) brittle fracture mechanics based on the Griffith theory and on Irwin's strain-energy release rate adaptations, (2) static tests on flawed butt welds, (3) static and dynamic tests on small butt weld flaws with and without residual stress, and (4) static tests on weld flaws controlled fields of high residual stress.