PSI - Issue 13

S.A. Atroshenko et al. / Procedia Structural Integrity 13 (2018) 1373–1377 S. A. Atroshenko et al. / Structural Integrity Procedia 00 (2018) 000–000

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Fig. 3. Waveforms of the current from the Rogowsky coil (1) and the signal from the photodiode (2). For the current with a period of 5 − 7 µ s (a); for the current with a period of 1 µ s (b); and for the pulse current with duration of 80 ns (c).

Fig. 4. Time dependence of the strength of annular samples made from copper. The thickness of the sample is 0 . 015 mm .

3. Experimental results

3.1. Testing

The experiments were carried out with rings of copper foils of 0 . 015 mm thick and 1 − 5 mm wide.Measurements of the radial pressures q ( t ) on the inner surface of the rings were made during the destruction with the the piezoelectric sensor developed by us. Further the circumferential fracture stress σ ( t ) the Laplace formula (1). Measurement of radial pressure σ ( t ) was carried out repeatedly from 5 up to 10 experiments for each time till destruction. Then the results were averaged. The curve of dependence strength on time was constructed from the midpoints. The results of the experiments made it possible to plot the time dependence of the strength of copper ring samples (Fig. 4).