Time History Forced Response in Nonlinear Mechanical Systems

A formulation of a digital filter method for computing the forced response of a linear MDOF mechanical system is proposed. It is shown how aliasing error effects can be avoided at the expense of a bias error. The bias error is however completely known and it is system independent, as it only depends on the sampling frequency used. The mechanical system is described by its modal parameters, poles and residues. The method is extended to include non-linear elements. A toolbox in MATLAB has been created where nonlinear elements with and without memory can be treated, as well as system described by coupled non-linear equations.