PSI - Issue 16

Leonid Lobanov et al. / Procedia Structural Integrity 16 (2019) 27–34 Leonid Lobanov, Nikolai Pashсhin / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 1. Schematic diagram of EDT of welded joints, where C – capacitive energy storage, K – power switch, q – fixing load, ED-electrode device, 1 – inductor, 2 – disc, 3 – electrode, 4 – specimen, 5 – assembly plate.

2.2. Mathematical model

A mathematical model of a non-stationary electro-physical process of electrodynamic treatment of welded joints was developed by Lobanov et al. (2016a) and mode characteristics for providing the parameters of current pulses, sufficient for effective control of residual stress state of metal structures were set on its basis. Adequacy and validity of the mathematical modelling of a non-stationary process in electromagnetic system were confirmed by experimental investigations, which were carried out on a pilot model of the designed device. Fig. 2 presents the calculated distribution of lines of equal density of current j in thickness z of plate of alloy AMg6 at L = 5  H, C = 5140  F, U ch = 500 V at the moment of time t = 71.2  s, which corresponds to value I max in the circuit. It is seen in Fig. 2 that the presented mode provides the current density value j  1 kA/mm 2 , which cam generate the effect of electroplacticity of alloy AMg6 being treated.

Fig. 2. Distribution of lines of equal current density j (kA/mm 2 ) in thickness of plate of alloy AMg6 at L = 5  H, C = 5140  F, U

ch = 500 V at the

moment of time t = 71.2  s, which corresponds to value I max in the circuit, where 1-electrode.

This is confirmed by data of Fig. 3, where the calculated distribution of lines of equal radial plastic deformations  r in thickness of plate of alloy AMg6 at EDT mode, similar to that used in Fig. 2, are shown, The given distribution of  r was caused by the effect of electrodynamic forces, occurring during passing the pulse current in the zone of electrode contact with the plate treated. It can be seen that electrodynamic forces provide the electroplastic deforming in the zone of treatment. It should be noted that the superposition of plastic deformations from EDT with