THE RAYLEIGH-RITZ METHOD WITH QUASI-COMPARISON FUNCTIONS IN NONSELF-ADJOINT PROBLEMS

In the determination of the first eigenmodes of continuous linear elas tic systems the Rayleigh-Ritz method is often used. It is also very us eful in the discretization of the elastic members of multibody systems undergoing large nonlinear motions. Recently the concept of quasi-com parison functions has been introduced for the Rayleigh-Ritz discretiza tion in self-adjoint eigenvalue problems, where it may lead to a consi derable improvement of the convergence when compared with other classe s of admissible functions. In this paper it is shown with a simple exa mple that a similar phenomenon also holds for nonself-adjoint problems . Since the exact solutions are known, precise information on the erro rs can be given.