A miniature multi-pulse series loading Hopkinson bar experimental device based on an electromagnetic launch

Area of Science:

• Materials Science and Engineering
• Mechanical Engineering
• Experimental Dynamics

Background:

• Classical split Hopkinson pressure bar (SHPB) testing typically employs single-pulse loading.
• Controlled multi-pulse loading is rarely utilized in SHPB research, limiting the study of complex material behaviors under dynamic stress.
• A need exists for advanced loading techniques to better understand material responses to sequential impacts.

Purpose of the Study:

• To introduce a novel technique for controlled multi-pulse loading in SHPB experiments.
• To develop and present a miniature multi-pulse series reluctance coil launcher for precise dynamic material testing.
• To enable detailed investigation of material dynamic responses under precisely controlled sequential loading conditions.

Main Methods:

• Development of a micro-multi-pulse series reluctance coil emitter comprising two single-stage reluctance coils and two impact bars.
• Generation of two successive loading pulses of identical amplitude by sequentially impacting the incident bar with the two impact bars.
• Control of the time delay between the two loading pulses by adjusting the distance between the impact bars and their launch speed.

Main Results:

• Successful implementation of a controlled multi-pulse loading technique for SHPB experiments.
• Demonstration of precise control over the delay between successive loading pulses.
• The developed reluctance coil launcher provides a reliable method for generating repeatable multi-pulse impacts.

Conclusions:

• The proposed precise multi-pulse loading technique is easily implementable in SHPB setups.
• This technique facilitates the measurement and study of the dynamic response of various materials under complex loading scenarios.
• The developed reluctance coil launcher offers a versatile tool for advanced materials research in dynamic mechanics.