Global Dynamic Stiffness Matrix Research Articles

Lower Bounds for the Resonant Frequencies of Nonuniform Frame Structures

AbstractThe theory and practice of computing rigorous lower bounds to eigenvalues through the methodology of intermediate problems is extended to general frame structures with nonprismatic beam elements. Intermediate operator constructions for each substructure are used to ensure bounding of the actual resonances from below. The assembly of the elemental intermediate problems into a global dynamic stiffness matrix is discussed together with computational results that illustrate the method applied to a simple planar frame.