Identification of a simulated continuous structure with discrete non-linear components using an extended modal model

In this paper a method capable of the identification of non-linear structures with many degrees of freedom is presented. The Non-Linear Resonant Decay Method achieves this by identifying an underlying linear modal model for the system. Force appropriation is then used to apply sinusoidal bursts to the structure at high levels of force. The system responses to these bursts are used in a regression analysis in modal space to yield a limited number of additional non-linear terms. The method is applied to a simulated continuous system representing a wing/engine structure with discrete non-linear components at the engine attachment points. The resulting identified non-linear modal model is used to generate response data which are compared with responses from the original system.