Some special phenomena and preliminary interpretations about measured strain signals from high-speed impact tests

During the last several decades, considerable efforts have been devoted to high-speed impact tests to investigate dynamic properties of materials, such as metal, alloy, ceramic, polymer, rock, concrete, brick, mortar etc. The purpose of impact or shock test is to study the crash-relevant or blast-relevant behaviour of engineering materials under high strain rates. According to different test purposes, sometimes the strain rate could be extremely high, i.e., up to 10,000 unit strain per second. In the School of Civil and Resource Engineering at the University of Western Australia, some impact tests on steel material and concrete material have been carried out recently, to calibrate the impact loading ability of an innovative blast simulator device. From the test results, some special phenomena about measured strain signals were observed and reported, which may have an unavoidable influence on properly describing material dynamic properties. In order to avoid misleading the consequent analysis on acquiring the genuine dynamic behaviour of material or specimen from high-speed impact tests, some important factors, from the point view of experimental technique are discussed in the current paper.