Repeated lateral impacts on steel beams at room and sub-zero temperatures

This paper experimentally and numerically investigates the effect of repeated impacts on the response of steel beams at room and sub-zero temperatures. Repeated dynamic impact tests were conducted on four beam models. Both ends of the beam models were fixed onto a strong bed. Repeated impacts were applied by releasing a knife-edge striker using a drop testing machine. The permanent deflections were measured after each impact test. For the repeated impact tests at sub-zero temperature the models were kept in cold chambers filled with dry ice and ethanol. The temperature histories were measured with thermocouples attached to the models. Numerical analyses were also performed to predict the damages done to the beams caused by repeated impacts. The calculations considered both the strain and strain rate hardenings. The strain hardening was reflected by using the stress-strain relationships obtained from the tensile tests of this study. However, the strain rate hardening was considered by adopting the empirical equations proposed by other researchers. Comparison of the numerical predictions with those of the test results showed reasonable agreements. (C) 2014 Elsevier Ltd. All rights reserved.