Error Analysis of Interface Friction Effect of Metal Material in Split Hopkinson Pressure Bar Test

Stress-strain curves of 38CrMoAl high-strength steel were reconstructed by split Hopkinson pressure bar（SHPB）test and finite element simulation. The effects of end-face friction coefficient（0, 0.1, 0.2, 0.3, 0.4, 0.5）, bullet incident velocity（20, 30, 40 m·s^－1）, sample length-diameter ratio（0.25, 0.50, 1.00）and sample shape（cylinder, cube）on the test error of peak stress and peak strain induced by end-face friction effect were studied. The results show that the test errors of peak stress and peak strain increased with the increase of end-face friction coefficient, and decreased with the increase of length-diameter ratio. With the same section area, the test error difference between cylindrical and cube samples was less than 2%. When the end-face friction coefficient was large, the test error could not be effectively reduced by controlling the bullet incident velocity. If the end-face friction coefficient of the sample was reduced below 0.1, or the length-diameter ratio of the sample was larger than 1.00, the end-face friction effect error could be effectively reduced. The stress concentration occurred in the middle and the edge of the end-face of the sample. With the increase of the length-diameter ratio of the sample, the proportion of the stress concentration in the total length of the sample decreased, and the influence of the end face friction effect decreased.