Model updating of a scaled piping system and vibration attenuation via locally resonant bandgap formation

This study presents a Finite Element (FE) model updating methodology of a piping system and demonstrates vibration attenuation at its resonant frequencies using tuned local resonators distributed along its length. An experimental laboratory scaled version of a prototype piping system inspired from existing piping structures in the oil and gas industry is assembled to study its dynamic behavior under laboratory conditions. A dynamic structural similitude analysis is carried out to derive scaling factors for frequencies and mode shapes between the prototype and scaled piping systems. These scaling factors are verified with the aid of both detailed and reduced-order FE models. Experimental natural frequencies and mode shapes are obtained based on the impact hammer modal test and the forced vibration sine sweep test and then compared with numerical results. Discrepancies between measured and computed results due to uncertainties in the FE model necessitate the use of an FE model updating technique to minimize the error between the predicted and the measured response. This updating strategy is carried out by iteratively adjusting parameters associated with the assumed boundary conditions until a relatively faithful computational model that can replicate the actual behavior of the structure is obtained. The updated reduced order model is then used to investigate the creation of locally resonant bandgaps centered at the first three resonant frequencies of the structure by embedding tuned resonant cantilever beams with tip masses along the length of the piping system. Using a harmonic response analysis, it is shown that an attenuation is obtained at all considered target frequencies with distinct edge frequencies appearing in the frequency response for the third mode of vibration.