A novel integrated tension-compression design for a mini split Hopkinson bar apparatus

A miniature integrated Split Hopkinson Bar (SHB) apparatus based on an innovative three-loading bar technique and a multi-stage electromagnetic driving technique was developed for both impact compression and tensile tests. The design principles of these techniques and the whole structure of this new device are discussed in detail. Compared to the traditional SHB apparatus which has a single-function, this new device can realize the integration of compression and tensile tests. Furthermore, due to the application of the electromagnetic driving technique, the whole structure of the SHB apparatus can be miniaturized with good reproducibility, reliability, and no noise, making it easier to move to different locations without the need for heavy gas launching systems used for some specialist tests. Under both impact compression and tensile conditions, a series of verification experiments were carried out on 2A12 aluminum alloy, proving that the new apparatus can conduct impact tension and compression tests for small specimen with high accuracy and reliability. The dynamic behavior of electrodeposited nickel fabricated by micromachining was investigated at a high strain rate of 1.2 × 10⁴ s.