ADAPTIVE EIGENFREQUENCY ANALYSIS BY IMPROVED r-AND h-ADAPTIVE FINITE ELEMENT METHOD BASED ON PERTURBATION AND ELEMENT ENERGY RATIO

摘要

A new adaptive technique of r-and h-version for vibration problems utilizing the matrix per-turbation theory and element energy ratio is proposed.In structural vibration analysis,through the r-conver-gence adaptive finite element process,mesh optimization can be realized.In the light of the judgement on thechanges in the magnitude of the element energy ratio,local refinement can be achieved in the process of h-convergence adaptive finite element so that more accurate finite element solutions can be obtained with as fewmeshes as possible.Many numerical examples are given and the proposed approach is shown to be feasibleand effective.