The Sensitivity Method in Stochastic Model Updating

Probabilistic and interval model updating methods are described, with particular attention paid to variability in nominally identical test structures due, for example, to the effect of accumulated manufacturing tolerances, or degradation of performance caused by wear of engineering components. In such cases the updating parameter distributions are meaningful physically either as PDFs or as intervals. Stochastic model updating is an inverse problem, generally requiring multiple forward solutions, which may be carried out very efficiently by the use of surrogates, in place of full FE models. The procedure is illustrated by experimental examples, including model updating of (i) a frame structure with uncertain locations of two internal beams and (ii) the DLR AIRMOD structure, which displays vibration characteristics very similar to those of a real aircraft.