International Journal of Mathematics and Mathematical Sciences
Volume 17 (1994), Issue 2, Pages 315-322

Existence and uniqueness of equilibrium states of a rotating elastic rod

M. B. M. Elgindi

Department of Mathematics, University of Wisconsin-Eau Claire, Eau Claire 54702-4004, WI, USA

Received 7 April 1992; Revised 25 June 1992

Copyright © 1994 M. B. M. Elgindi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A flexible rod is rotated from one end. The equilibrium equation is a fourth order nonlinear two-point boundary value problem which depends on two parameters λ and α representing the importance of centrifugal effects to flexural rigidity and the angle between the rotation axis and the clamped end, respectively. Previous studies on the existence and uniqueness of solution of the equilibrium equation assumed α=0. Among the findings of these studies is the existence of a critical value λc beyond which the uniqueness of the “trivial” solution is lost. The computations of λc required the solution of a nonlinear bifurcation problem. On the other hand, this work is concerned with the existence and uniqueness of solution of the equilibrium equation when α0 and in particular in the computations of a critical value λc such that the equilibrium equation has a unique solution for each α0 provided λ<λc. For small α0 this requires the solution of a nonlinear perturbed bifurcation problem.