Heaviside Function: A Heaviside function is a unit step function, usually denoted by H. It is a discontinuous function whose value is zero for negative argument and one for a positive argument.

The Heaviside function H(x) is defined as

=

This Heaviside function can be used for modelling the added masses. The added masses have been considered cylindrical in shape. Thus, a Heaviside function who has unit value within the cylinder and zero elsewhere can be chosen.

The Heaviside function chosen for a plate with origin at centre and one mass added in each quadrant is:

For first quadrant.

For second quadrant.

For third quadrant.

For fourth quadrant.

For the plate, the Heaviside function can be taken as the summation of all the above four functions.