Testing of Welded and Machined A36 Steel T-Joint Configuration Specimens 2019-01-0535
When evaluating fatigue life prediction methodologies, fatigue tests must be run to understand how well the fatigue life prediction methodology correlates to those fatigue test results. For this latest SAE Fatigue Design and Evaluation effort, fatigue tests were run by loading, in bending, both welded and machined T-Joint specimens that have the same geometry. The test rig setup consisted of a horizontally mounted actuator, with pinned joints at both ends, where the load is applied to the top of the vertical leg of the “upside down T” of a T-Joint specimen, while the horizontal legs of the “upside down T” were clamped to the bedplate. Specimens were tested until failure or until the specimen was unable to carry the commanded load. They were cycled under constant amplitude (at several load levels and R ratios), block-cycle, and variable amplitude loadings. Welded and machined T-Joint specimens of the same geometry were included in the test plan such that fatigue life predictions could be compared to test lives for each case. Those comparisons would demonstrate the methodology’s relative predictive ability with and without welds, with and without residual stresses, etc... Fatigue tests were successfully completed on 30 T-Joint specimens (13 machined and 17 welded).
Eric M. Norton, Casey Gales, Ryan Blodig, Michael Lister, Tom Cordes