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THERMAL STRESS STATE OF A BIMETALLIC PLATE SUBJECTED TO PULSED ELECTROMAGNETIC ACTION O. R. Hachkevych,1 R. S. Musii,2 and N. B. Mel’nyk 1 We formulate a problem of thermomechanics for an infinite bimetallic plate of constant thickness subjected to nonstationary electromagnetic action and present a relationship for the evaluation of the load-carrying capacity of the plate. A procedure of approximate determination of the parameters of the electromagnetic fields, temperature, and stresses by using the quadratic approximation of the distribution of key functions over the thickness of layers of the plate is proposed. The solution of this problem is obtained for the electromagnetic action in the mode with pulsed modulating signal. We present the results of numerical investigation of the components of the stress tensor and stress intensities in the plane of contact of the constituent layers for a frequency of the carrier signal lying outside the neighborhood of the resonance frequencies and for the first resonance frequency.

Bimetallic plates serve as structural elements of numerous engineering structures and are used, in particular, for manufacturing contact adapters and carrying and conducting elements of special devices used for the transformation of the electromagnetic energy [1, 7, 13, 14]. In the course of operation of these devices under the action of nonstationary electromagnetic fields (EMF), it is necessary to preserve the mechanical properties of the contact joint determined by the stress intensity σi on the interface for different time parameters of the field. In the literature, one can find numerical schemes aimed at finding the thermal stress states of bimetallic plates subjected to induction heating by constant EMF [2, 11] and homogeneous conducting bodies subjected to the action of pulsed EMF [3, 4, 9]. However, the thermal stress state of bimetallic bodies under the action of pulsed EMF is studied quite poorly. In the present work, we consider the dynamic problem of thermomechanics for a bimetallic plate subjected to the action of pulsed EMF with amplitude modulation and present the results of numerical investigations of the stress intensity in the plane of contact of layers of the plate for different parameters of the EMF. Formulation and Computational Scheme of the Problem Consider an infinite bimetallic plate of constant thickness related to a Cartesian coordinate system O x y z. The plane x O y coincides the plane of contact of the layers p = 1, 2, and the Oz-axis is perpendicular to the bases of the plate: z = – h1 and z = – h2 , where h1 and h2 are the thicknesses of the layers. The materials of the layers are homogeneous, isotropic, and nonferromagnetic and their physicomechanical characteristics are constant. Under the action of nonstationary EMF, the plate is characterized by the presence of Joule heat release Q

( p)

and ponderomotive forces F ( p) promoting the formation of nonstationary temperature and mechanical

1 Pidstryhach Institute for Applied Problems in Mechanics and Mathematics, Uk