Advanced analysis of metal wind turbine support towers

Metal wind turbine support towers present a fascinating object of study for the structural analyst, a consequence of its multi-segment geometry exhibiting a complex interaction between stability, plasticity and imperfection sensitivity at the ultimate limit state. As a consequence of recent developments in research and design practice, including Standards development, an opportunity has arisen to establish a unique and long-term partnership between industry and academia to enhance the analysis and design of these complex structures. The proposed 4-year PhD project, to be supervised jointly by Dr Sadowski and Dr Seidel, aims to achieve the following:
- To characterize the measured surface imperfections in built wind turbine support towers and consequences for fabrication tolerances.
- To determine appropriate partial safety factors for wind turbine support towers under uniform compression and bending loads, achieving the target reliability intended by the governing wind turbine standard IEC 61400.
- To develop an efficient algebraic design procedure, based on Reference Resistance Design (RRD), for wind turbine support towers under predominately bending loads calibrated against results from an optimization engine for wall thicknesses based on accurate computational representations of limit states in arbitrarily chosen wall segments.

The bulk of the student's efforts will be computational in nature, consisting of both processing of field measurement data and in the running of finite element simulations:
- The student will process and analyse raw data originating from field surveys of surface imperfections in existing metal wind turbine support towers. They will perform a harmonic analysis of this data to identify dominant geometric components in both shape and amplitude, and relate these to manufacturing processes.
- The student will perform extensive finite element simulations on models representing typical tower geometries, as well as those from the full range of practical slendernesses. These models will include idealizations of both scale laboratory and full-scale constructed shells, for direct statistical comparison. The student will perform extensive parametric studies with these models.
- The student will synthesise the outcomes of the above into recommendations that are useful for design in the context of IEC and Eurocode Standards.