Analysis of test system misalignment in the creep test
(Previously announced in STAR as N80-22466)
Engineering topics
Publications and source records attributed to Wang, T. P..
(Previously announced in STAR as N80-22466)
(Previously announced in STAR as N80-19564)
Sheet type rectangular 1100-0 aluminum specimens were tested. The creep strain at the geometric centerline of the specimen is different than that at the neutral axis, and decreases with time. The effect of misalignment, which decreases with creep time, is minimized when creep tests are conducted with long pullrods and large initial strain level (high creep stress).
The effects of test system misalignment are analyzed for dynamic tension tests using sheet type rectangular 1100-0 aluminum specimens. The strain rate is assumed constant only on the natural axis of the specimen even though the specimen is subjected to a constant strain rate test. The results include: (1) the lower the strain rate, the more significant the misalignment errors become; (2) misalignment errors of 50% are found at the extreme fibers of the specimen; (3) the strain rate variation in the cross section decreases with increasing plastic strain and vanishes at plastic strain equal to 0.8% at the midspan of the specimen; and (4) the neutral axis shifts toward the centerline of the specimen as the plastic strain increases, but it reaches a limit and does not completely move back to the centerline.