Curved finite elements by the method of initial strains.
A simple procedure has been presented for combining two discrete linear vibratory systems by a discrete spring or damper. The procedure leads to an exact formulation of the characteristic equation for which the roots can be readily found by a NewtonRaphson iteration scheme. After the initial coupling is completed, successive eigenvalue modifications can be used to add additional discrete elements as required. J. T. Weissenburger neglected damping and used back substitution to eliminate the added degree of freedom whereas the procedure discussed in this note takes damping into account and does not limit the size of the added system. E. H. Dowell used Lagrange multipliers to derive a characteristic equation similar in form to Eq. (6) which can be used to join elastic vibratory systems of unlimited size, but, like Ref. 4, he also neglected damping. AXIS OF REVOLUTION