An experimental study of square tube crushing under impact loading using a modified large scale SHPB

This paper presents an experimental study on square tubes made from a rate insensitive material under static and impact loading. Rate insensitivity of the base material (Cu–Zn alloy) is confirmed by static and dynamic tests on small samples cut from the tubes. A direct impact large scale Hopkinson bar (80 mm diameter, 10 m length) system is used to perform tube crushing tests. A two-point measurement method is applied to extend measuring duration of the pressure bar, which is usually limited by its length. The proposed method permits to monitor the whole tube crushing process. Static and impact tests (7–15 m/s) on these square tubes reveal that there is a significant increase under impact loading of both initial and successive peak loads with respect to quasi-static loading. Such a study is useful for the understanding of strength enhancement under impact loading observed for cellular materials such as honeycombs.