TIME-DOMAIN ANALYSIS OF FLEXIBLE FOUNDATIONS USING LANCZOS VECTORS

An analytical procedure to obtain the response of embedded flexible fo undation in time domain is described. The procedure makes use of large domain for discretization along with coordinate transformation using Lanczos vectors. The responses are obtained in time domain using an ad aptive direct integration method. The scheme has the ability of error estimation due to temporal discretization and coordinate transformatio n. The procedure has been applied to three-dimensional flexible founda tions. The compliance functions of the foundations have been obtained for all modes of vibration. The computational scheme has also been use d to analyze the response of a machine foundation transmitting nonharm onic but periodic forces. The present method has all the advantages of time domain scheme, which is local in space and time with small compu tational effort.