Foundations of offshore wind turbines: a review

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Response of Foundations to Random Cyclic Loads

Variable amplitude cyclic loads due to natural phenomena are common for laterally loaded piles. A series of small scale cyclic model test have been performed in the Boundary Layer Wind Tunnel Laboratory. Random loads from a boundary layer wind field were applied to a model consisting of a pile, pole and plate. The same setup was also tested under static conditions for comparison. Hyperbolic projection was used to represent the load – displacement relations. Initial stiffness and hyperbolic capacity were obtained from this method. The number of load cycles was found to affect the behavior of the laterally loaded piles. Load cycles were counted using the Rainflow method. Hyperbolic capacity and initial stiffness were found to decrease with increasing numbers of loading cycles. Displacement for laterally loaded piles was greater in the wind tunnel tests compared to static tests. Alternative approaches were used to assess the accumulation of ground-line displacement

Wind turbines and seismic hazard: a state-of-the-art review

Wind energy is a rapidly growing field of renewable energy, and as such, intensive scientific and societal interest has been already attracted. Research on wind turbine structures has been mostly focused on the structural analysis, design and/or assessment of wind turbines mainly against normal (environmental) exposures while, so far, only marginal attention has been spent on considering extreme natural hazards that threat the reliability of the lifetime-oriented wind turbine's performance. Especially, recent installations of numerous wind turbines in earthquake prone areas worldwide (e.g., China, USA, India, Southern Europe and East Asia) highlight the necessity for thorough consideration of the seismic implications on these energy harnessing systems. Along these lines, this state-of-the-art paper presents a comparative survey of the published research relevant to the seismic analysis, design and assessment of wind turbines. Based on numerical simulation, either deterministic or probabilistic approaches are reviewed, because they have been adopted to investigate the sensitivity of wind turbines' structural capacity and reliability in earthquake-induced loading. The relevance of seismic hazard for wind turbines is further enlightened by available experimental studies, being also comprehensively reported through this paper. The main contribution of the study presented herein is to identify the key factors for wind turbines' seismic performance, while important milestones for ongoing and future advancement are emphasized

M.Sc. in Civil and Structural Engineering:3rd Semester and Master’s Thesis Ideas 2010

The following pages contain a list of project ideas proposed by the scientific staff at the department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalouge may form the basis for long and short candidate projects as well as regular 3rd semester projects at the M.Sc. programme in Civil and Structural Engineering.The following pages contain a list of project ideas proposed by the scientific staff at the department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalouge may form the basis for long and short candidate projects as well as regular 3rd semester projects at the M.Sc. programme in Civil and Structural Engineering