EFFECT OF REPEATED LOADS ON THE LOW TEMPERATURE FRACTURE BEHAVIOR OF NOTCHED AND WELDED PLATES

The influence of repeated loadings on the susceptibility of weldments to fracture in a brittle manner was studied for an ABS-Class C steel. The test members consisted primarily of 12, 24 and 36 in. wide notched-and-welded specimens that, at low temperatures, have been known to provide low-stress brittle fractures. The repeated loads or loading history was found to affect the fracture behavior of the weldments. In all but one instance the fracture stresses obtained for the notched-and-welded wide plates were greater than the stresses to which the members were subjected during the repeated loadings. Furthermore, the repeated loadings appeared to eliminate the two-stage fractures observed in some of the tests of as-welded specimens. This latter condition is in general desirable, but only if the fracture stress is raised to a high-stress level. (Author)