Production of short mechanical impulses by means of eddy currents

There is currently much interest in the use of eddy-current methods to produce mechanical impulses which are, for example, applied to aerodynamic surfaces as a method of removing ice. A Hankel-Laplace transform method has been used to obtain an expression for the force between a metal plate and an extended coil through which a transient current waveform passes. Experimental tests using various plate thicknesses and conductivities, frequencies and coil geometries show that the expression agrees well with the data. Effects due to the transient nature of the current become more important at lower frequencies. Expressions for the currents and fields within the plate are given and may be used to obtain the spatial distribution of the forces on the plate.