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

Area of Science:

• Materials Science
• Mechanical Engineering
• Experimental Physics

Background:

• Traditional Split Hopkinson Bar (SHB) apparatuses are often single-function and bulky.
• Miniaturization and integration of testing capabilities are desirable for advanced material characterization.
• Electromagnetic driving offers potential for compact and reproducible dynamic testing systems.

Purpose of the Study:

• To develop a miniature, integrated Split Hopkinson Bar (SHB) apparatus capable of both impact compression and tensile tests.
• To demonstrate the feasibility and advantages of a three-loading bar technique and electromagnetic driving.
• To investigate the high strain rate behavior of materials using the novel apparatus.

Main Methods:

• Development of a miniature SHB apparatus employing a three-loading bar technique and multi-stage electromagnetic driving.
• Integration of compression and tensile testing functionalities within a single device.
• Verification experiments on 2A12 aluminum alloy and dynamic behavior investigation of LIGA-deposited nickel.

Main Results:

• The new apparatus successfully integrates impact compression and tensile tests, overcoming limitations of traditional SHB devices.
• Verification tests on 2A12 aluminum alloy demonstrated high accuracy and reliability for small specimens.
• The dynamic behavior of LIGA-deposited nickel was investigated at a high strain rate (1.2 × 10(4) s(-1)), revealing strain rate sensitivity.

Conclusions:

• The developed miniature integrated SHB apparatus offers a versatile, reliable, and portable solution for dynamic material testing.
• The electromagnetic driving and three-loading bar techniques enable miniaturization and enhanced functionality.
• The apparatus is suitable for investigating the high strain rate mechanical properties of various materials, including micro-machined components.