Propagation of variances of FRFs through FRF-based coupling calculations

摘要

In many engineering cases, uncertainties will exist on the frequency response functions (FRFs) of componentrnmodels. Possible sources of uncertainty in the mechanical structure are uncertain material properties, loadingrnconditions or geometry. When bringing together the component models together and interconnecting themrninto an assembly, it is of high interest to be able to predict the uncertainty of the response of the assembledrnsystem. This paper outlines a technique allowing such an uncertainty characterization. The underlying idearnof the approach is based on variance propagation through FRF-based coupling techniques. An analyticalrnapproximation using a mean value first order second moment approach (MV) is proposed, whichrnsignificantly reduces the computational cost involved in a probabilistic uncertainty quantification through therncommon Monte Carlo (MC) simulation technique. A two-component carbody-subframe assembly modelrnindicates that the overall efficiency of the analytical approach is superior to the classical Monte Carlornsimulation approach, while the accuracy obtained with both approaches is very similar.