Controlled multipulse loading with a stuffed striker in classical split Hopkinson pressure bar testing.

Area of Science:

• Materials Science
• Mechanical Engineering
• Experimental Mechanics

Background:

• Investigating loading history-dependent material phenomena requires controlled multipulse loading.
• Classical split Hopkinson pressure bar (SHPB) testing rarely explores controlled multipulse loading.
• Existing methods lack precise control over multiple impact pulses.

Purpose of the Study:

• To present a novel technique for controlled multipulse loading in SHPB testing.
• To enable precise control over the timing and separation of multiple loading pulses.
• To facilitate the study of dynamic material responses under complex loading histories.

Main Methods:

• Development of a 'stuffed striker' comprising a striker tube, inner striker bar, and adjustable gap.
• Utilizing the stuffed striker in conjunction with the Lindholm technique for multipulse generation.
• Experimental validation of the technique using double- and triple-pulse loading on polycrystalline copper (Cu).

Main Results:

• The stuffed striker successfully generates two separated loading pulses upon impact.
• The gap within the striker allows continuous tuning of pulse separation (dwell time) from zero to hundreds of microseconds.
• The technique demonstrated feasibility and flexibility for acquiring dynamic data under controlled double- and triple-pulse loading.
• Successful application to polycrystalline Cu, validating the method's effectiveness.

Conclusions:

• A novel, readily implementable technique for controlled multipulse loading in SHPB testing has been developed.
• This method allows for precise control over pulse separation, crucial for studying history-dependent phenomena.
• The technique is versatile and applicable to a wide range of materials for dynamic response investigation.