ARTÍCULO
TITULO

Soil?Structure Interactions for the Stability of Offshore Wind Foundations under Varying Weather Conditions

Liang Cui    
Muhammad Aleem    
Shivashankar and Subhamoy Bhattacharya    

Resumen

Fixed-bottom foundations of offshore structures, mainly monopiles, are subject to extreme events and other critical cyclic nature loads. Since offshore wind turbine structures are slender, the manufacturers of offshore wind turbines give a range of frequencies for safe operation during a structure?s life cycle. Highly reliable measurements and accurate determination of shear moduli and damping ratios are crucial to ensure the stability of these structures, for example, to avoid the resonance of the structures. Because foundation?soil properties change over a period of time due to various environmental factors, this should be taken into consideration for designs. In the current investigation, behaviours of dry sand under dynamic loads were explored. Cyclic loads of strain amplitudes of 0.05%, 0.1%, 0.25% and 0.5% were carried out in a cyclic simple shear apparatus to explore the evolution trend of the stiffness and damping ratio of the soil. Attempts were made to simulate varying weather conditions by conducting cyclic tests with different strain amplitudes representing normal weather conditions and extreme weather conditions. It was found that soil dynamic properties vary remarkably at first and then tend to stabilise under cyclic loading with the same strain amplitude. However, with varying strain amplitude, property variations continue further. From numerical analyses using the discrete element method, it was found that this is due to the disturbance of soil, causing further particle rearrangements and soil compactions, following a sudden change of strain amplitude, which leads to further property variations.

 Artículos similares

       
 
Michiel van der Vlag, Lionel Kusch, Alain Destexhe, Viktor Jirsa, Sandra Diaz-Pier and Jennifer S. Goldman    
Global neural dynamics emerge from multi-scale brain structures, with nodes dynamically communicating to form transient ensembles that may represent neural information. Neural activity can be measured empirically at scales spanning proteins and subcellul... ver más
Revista: Applied Sciences

 
Jason K. Jolliff, Travis A. Smith, Sherwin Ladner, Ewa Jarosz, Mark David Lewis, Stephanie Anderson, Sean McCarthy and Adam Lawson    
The southward propagation of cold-air frontal boundaries into the Gulf of Mexico region initiates a cascade of coupled air?sea processes that manifests along the coastlines as an apparent brightness anomaly in the ocean color signals. Our hypothesis is t... ver más

 
Mengyu Li, Xizeng Zhao, Mingjian Yin, Yiyang Zong, Jinyou Lu, Shiming Yao, Geng Qu and Hualong Luan    
The interaction between solitary waves and underwater barriers is investigated using our in-house code, entitled VPM (volume-average/point-value multi-moment)?THINC/QQ (THINC method with quadratic surface representation and Gaussian quadrature)-coupled m... ver más

 
Tze How New, Zhen Wei Teo, S. Li, Z. A. Ong and Björn Nagel    
Flow behavior and aerodynamic performance of a small-scale joined-wing unmanned aerial vehicle (UAV) was studied experimentally and numerically under various pitch and yaw angle combinations in subsonic flow conditions. Selected numerical results are com... ver más
Revista: Aerospace

 
Changbao Yang, Zhisheng Wang, Yuanwei Lyu, Jingyang Zhang and Ben Xu    
With increasing demand for load capacity and dynamic responses, the new generation of Gas Dynamic Foil Bearings (GDFB), assembled from preloaded elastic multi-leaf foils, has been put forward. It exhibits steady and dynamic characteristics that are more ... ver más
Revista: Aerospace