Efficient Computation of Spectral Moments forDetermination of Random Response Statistics

摘要

This paper will first review the use of temporal spectral moments, and then propose an efficient runningrnsum technique to determine the spectral moments frequency by frequency. Combining this summationrnprocess with modal superposition techniques allow a significant reduction in input and output file sizesrnand computational time.rnThe proposed technique uses finite element analysis (FEA) to generate modal vectors that are postrnprocessed using mode superposition techniques to calculate the power spectral density (PSD) moments,rneliminating the need to form PSD response functions. This requires storage of only the modal responsernand force vectors and the running sum of the PSD moments. Once the moments of the PSD arerndetermined, the random response statistic calculations are a straightforward problem. Two examplernproblems are given: a simple cantilever beam and a detailed optical telescope. These examples show howrndifferent problems can be solved using the proposed technique.