A novel electromagnetic loading technique for intermediate strain rate testing on metals

This study presents an experimental technique for intermediate strain rate (ISR) testing, capable of achieving strain rates ranging from 10 s−1 to 250 s−1. A design of short elastic bars for dynamic load measurement was introduced and validated through both simulations and experiments. This technique is able to generate two types of stress waveforms: sinusoidal and quasi-trapezoidal. Using multiphysics simulations, the influences of capacitance, inductance and resistance on the width and amplitude of the current pulse were systematically analyzed. The effect of bar length on stress wave propagation was examined, revealing that short bars enable stable loading on the elastic bars. ISR tests were conducted on 6061 aluminum alloy and TA2 titanium. The results demonstrate that this technique can generate stress pulses ranging from 1 ms to 8 ms in duration and achieve engineering strain rates from 10 to 250 s⁻¹, with strain rate fluctuations not exceeding 15%. The maximum strain of the specimens is 0.24. Compared to sinusoidal wave loading, quasi-trapezoidal stress waves maintain a constant ISR, enabling specimens to reach stress equilibrium in 1 ms.