Benchmark Cyclic Plastic Notch Strain Measurements

Abstract

Plastic strains at the roots of notched specimens of Inconel 718 subjected to tension-compression cycling at 650°C are reported. These strains were measured with a laser-based technique over a gage length of 0.1 mm and are intended to serve as “benchmark” data for further development of experimental, analytical, and computational approaches. The specimens were 250 mm by 2.5 mm in the test section with double notches of 4.9 mm radius subjected to axial loading sufficient to cause yielding at the notch root on the tensile portion of the first cycle. The tests were run for 1000 cycles at 10 cpm or until cracks initiated at the notch root. The experimental techniques are described, and then representative data for the various load spectra are presented. All the data for each cycle of every test are available on floppy disks from NASA.