Operating Deflection Patterns Under Non-Stationary Order Related Forces

In this paper, an interesting structural dynamics technique is presented to represent an operating deflection pattern, under order related forcing loads. In this technique, the measurements are performed using the Phase Assigned Spectrum technique with the use of reference and roving response accelerometers. Rotating components in car engines generate cyclic excitation forces at the fundamental rotational frequency and its harmonics and sub-harmonic components. This excitation will result in structural resonances being excited by those particular orders, at specific rotational speeds.

The paper discusses in general the use of Order Tracking analysis under non-stationary conditions, for the determination of order-tracked deflection shapes obtained by Phase Assigned Spectrum analysis. A Vold-Kalman Order Tracking analysis is also performed on the set of data for extraction of time order waveforms or Phase Assigned Orders.