Dynamic Disturbance Substructuring

Structural limits are constantly pushed to improve engineering structures. In doing so, the presence of nonlinear dynamics arising from joints and interfaces are becoming an increasing problem. An interface is a connection between two structural parts, such as bolted joints, rivets, and gears. The problem is that we cannot yet predict and describe the dynamic effects arising from an interface. We need better models to avoid structural failures and increase the lifetime of engineering designs. The project objective is to develop Dynamic Disturbance Substructuring for identifying and characterising nonlinear interfaces in complex engineering structures. A Dynamic Disturbance (DD) can be any slight change in the system affecting the vibrational response, imposed as a known parameter, e.g. a slight change in stiffness or mass. By measuring vibrations of the system with and without the DD, two independent sets of information about the system are obtained, which, together with state-of-the-art dynamic substructuring approaches, allow robust estimation of interface dynamics. Using DD for nonlinear identification is unique to this project. Through numerical modelling, simple experimental setups and optical measurement for verification, the aim is to provide a new method for identifying nonlinear joint dynamics and increase confidence in model predictions.