Lanczos-iteration Method for Frequency and Buckling Analysis

The Lanczos-iteration method for frequency and buckling analyses with contact is available in ADINA. This capability significantly reduces for some problems the computation time when compared with using the Bathe subspace iteration method.

The animation above shows one of the mode shapes of the front end of a tractor with 1,217,556 degrees of freedom and 3,416 contact degrees of freedom. The mesh is shown below.

The structure is first statically loaded (through pre-stressed bolt elements) and then subjected to frequency analysis using the restart option. The problem was run on an IRIX64 gs2 6.5 IP27 machine with 8 processors, using the Lanczos-iteration method to solve for the eigenvalues. The performance is shown in the following figure.