PSI - Issue 50

Alekseev D.I et al. / Procedia Structural Integrity 50 (2023) 17–26 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

22 6

Fig. 4. Results of finite-element modeling of the magnetic-pulse deformation of the thin ring: a) the geometry of the magnetic system with the distribution of the current density at a time moment 1 ms; b) graphs of the dependencies of currents in the coil and ring on time; c) graphs of the dependencies of magnetic radial pressure in the middle, side and temperature in the middle of the ring on time. 4.2. Uniaxial tension A study of high strain rate tension of the wire can be realized by magnetic-induction loading of a conductive disk 1 to which one end of the test sample 3 is rigidly fastened (Fig. 5). Here, when the pulse current generator is discharged to the cylindrical solenoid 2 (Fig. 5), a current is induced in the conducting disk and magnetic pressure acts. Under the action of pressure, the disc moves and tensile the sample.

Fig. 5. Magnetic-induction system for uniaxial tension

Under quasi-static loading, the deformation of the wire is determined by the differential equation:

2 d l

( )    

( ) w m d S P t S  

(6)

m

2

dt

where ε = (l -l 0 )/l 0 – strain, l; l 0 – initial and current length of wire, σ(ε) – stress-strain curve, P m – magnetic pressure acting on the disk, S w ; S d – cross-section of the wire and the area of the lower boundary of the disk. Current measurement provided with the use of the Rogowski coil allows determining magnetic pressure P m (t) by finite element modelling of magnetic field, displacement of the disk measured by the high-speed camera we allow to verify the stress-strain curve by expression (6) or by finite-element modelling. The results of uniaxial high strain rate tension of samples with an initial length equal to 10 mm are shown in Fig. 6. Strain rates in shown experimental results were up to 2500 1/s for copper and 3000 1/s for aluminium.