Abstract
Computational modal analysis performed using finite element analysis is an established method for estimating the modal parameters of complex structures. This work aims to provide insight into the techniques necessary to accurately model structural components within an aircraft by performing computational modal analysis on a rear-mounted pump support structure. The results of this analysis will be used to further aid in the understanding of the vibratory transmission path from the support structure to the aircraft cabin. The frequency response functions were used to validate the finite element model via a visual and analytical comparison against experimental data. A modal frequency response analysis was used to estimate the dynamic response at a discrete set of points on the structure. A model validation study showed an excellent correlation between the experimental and computational results for frequencies between 100–2000 Hz with an average percent difference of the centre frequencies of 9.4%. The agreement between the two sets of results across the 20–4000 Hz bandwidth deteriorated slightly to 11.7 %. Modifications were made to the webbing of the pump support yoke as well as the in-board and out-board isolator plates. These tests confirmed that differences between the frequency responses of the original and modified finite element models can be justified using modal analysis theory. It was found that these particular structural design changes did not significantly influence the modal response of the structure. The methodology presented in this work provides an outline for future modelling and analysis of aircraft structural designs.