Browsing by Author "Wang, L."

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    Development of a stochastic computational fluid dynamics approach for offshore wind farms
    (IOP, 2018-06-19) Richmond, Mark; Kolios, Athanasios; Pillai, V. S.; Nishino, Takafumi; Wang, L.
    In this paper, a method for stochastic analysis of an offshore wind farm using computational fluid dynamics (CFD) is proposed. An existing offshore wind farm is modelled using a steady-state CFD solver at several deterministic input ranges and an approximation model is trained on the CFD results. The approximation model is then used in a Monte-Carlo analysis to build joint probability distributions for values of interest within the wind farm. The results are compared with real measurements obtained from the existing wind farm to quantify the accuracy of the predictions. It is shown that this method works well for the relatively simple problem considered in this study and has potential to be used in more complex situations where an existing analytical method is either insufficient or unable to make a good prediction.
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    New reduction factor for Cracked Square hollow section K-joints
    (Elsevier, 2018-02-11) Vipin, Sukumara Pillai; Kolios, Athanasios; Lie, S. T.; Wang, L.
    Cracks are commonly observed at the hot spot stress location of tubular joints and it can be due to fatigue, accidental damage or corrosion. As a consequence, the plastic collapse load (Pc) of the tubular joints is reduced, and hence it is necessary to produce design guidance which can safely be used to estimate the static residual strength of cracked tubular structures in practice. This paper proposes a new expression for determining the reduction factor (FAR) of cracked square hollow section (SHS) K-joints. A completely new and robust finite element mesh generator which is validated using the full scale experimental test results is used for the parametric study to propose the new FAR expressions for cracked SHS K-joints. The crack area and the brace to chord width ratio (β) are shown to have the most profound effect on the Pc load of cracked SHS K-joints. For a given value of crack area, the variation of the FAR values is up to 3.6% for different values of β. Furthermore, the FAR values calculated using the existing equation given in the latest BS 7910:2013 + A1:2015 for circular hollow section (CHS) joints are revealed to be conservative up to 23.5%.