This fully funded PhD is a joint venture between the Dynamics Research Group at the University of Sheffield and Ramboll Oil & Gas, leading engineering consultants. The project will pursue an innovative means of assessing the health of offshore structures.

On a number of structural monitoring system (SMS) projects, complex nonlinear behaviour of offshore structures has been observed. Characterisation of the nonlinearity may provide critical diagnostic and prognostic information. At present the structures can only be analysed by use of tools with assumptions of linear and stationary structural behaviour as no general tools for nonlinear system identification are available. Determination of the dynamic characteristics for a structure exhibiting nonlinear behaviour by assuming linearity and stationarity may lead to very misleading results. As a consequent fatigue analyses based on an updated FE model using linear methods to determine dynamic characteristics is very uncertain and the impact of this needs to be assessed and quantified if possible.

It is, therefore, vital to know if a structure is behaving nonlinearly in the operative range, and to detect and estimate the impact of the nonlinearity both qualitatively and quantitatively. Only then can it become possible to assess the need for nonlinear analysis depending on the type of analysis and application.

The research proposed here aims to provide insight into the nonlinear behaviour exhibited by structures and propose practical solutions to improve confidence in simulation results by introducing methods for FE model analysis and updating in the presence of nonlinear behaviour that are fit for purpose. A pragmatic approach is needed to develop a set of tools applicable for handling nonlinear behaviour to be used in connection with FE model updating based on current FE software.

The start date for this project will be November 2014.

For further information about this project please contact Dr Elizabeth Cross (e.j.cross<στο>sheffield.ac.uk)

Requirements:
This PhD program would be suited to any student with a good engineering, mathematics or computer science degree (2:1 or higher)

Funding details:
This studentship covers the cost of tuition fees and provides an annual tax-free stipend at the standard UK research rate (£13,863 in 2014/15), with the possibility that this amount may be topped up. 
Please note, this position is open to UK and EU citizens only.