The effect of test system misalignment in the dynamic tension test

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.