【作者】 夏露；

【导师】 康海贵；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2012， 硕士

【摘要】 风能是一种清洁、安全、永续的可再生能源。相对于陆上风电,海上风电资源更丰富,前景更为广阔,但同时也处于更为复杂的海洋环境之中,海上风机基础结构在各种环境荷载(如风、波浪、海流等)作用下的安全性与稳定性,一直是研究领域中的重点与难点。因此,开展风机基础结构在主要环境荷载作用下的动力分析与疲劳分析对风机在服役期内的安全与使用有着非常重要的意义。根据海床地质条件,选择三脚架桩式基础进行分析,主要研究内容包括：1)对主要环境荷载进行分析计算。采用五阶Stokes波理论与Morison方程计算波流共同作用下斜桩与竖桩的波流荷载；对于动力分析,采用P-M波浪谱确定波面运动过程,进而确定波流荷载时程；根据风的特性采用滤波法模拟不同高度处的风荷载时程。2)采用有限元分析软件ANSYS,建立支撑结构有限元模型,分别计算支撑结构在正常工况与极端工况时风、浪荷载作用下的动力响应,根据计算结果,确定结构承受的主导荷载,并以随机主导荷载叠加最大次要荷载的荷载组合方式组合风浪荷载,计算耦合荷载作用下结构的动力响应。结果表明,风机荷载为主导荷载,正常工况较极端风况结构响应更大,耦合荷载作用下支撑结构的响应主要反映了主导荷载—风荷载的随机特性。3)采用基于S-N曲线和线性累积损伤准则的疲劳计算方法,对海上风机基础应力集中显著的关键位置的疲劳损伤进行了计算。采用广泛使用的热点应力法计算应力幅值,根据S-N曲线与疲劳设计因子计算出结构的疲劳损伤。分别计算了结构在风机荷载与波浪荷载作用下的疲劳损伤度,再对二者进行叠加,进而求得结构位置在两种荷载作用下的疲劳损伤度。更多还原

【Abstract】 Wind is a renewable energy which is clean, safe and permanent. Comparing to the land wind power, the offshore wind power has a more abundant resource and a vaster future. Meanwhile, the offshore wind turbine structures face a more complex ocean environment. They suffer kinds of stochastic loads which changes with time and space, such as wind, wave and current and so on. Therefore, the safety and stability of the structures under those loads are the difficulty and emphasis points.. So, it is so important to research the dynamical analysis under main environment loads and the fatigue analysis for the safety and operation in the service period.According to the geological conditions of seabed at the site, the Tripod-Foundation is chosen for the wind farm. The paper mainly emphases on the following contents:1) The main environment loads are calculated. It is used the nonlinear Stokes5wave theory and Morison equation for wave load. Time history curve of wave load is got by changing from P-M wave spectrum. Time history curve of wind load at different elevation is got by filter method.2) Build support structure finite-element model in ANSYS, The dynamical analysis under wave and wind loads was made for the extreme and normal working conditions. We can ensure the main loads from results, then the coupling loads of stochastic mian loads with maximum miner loads are applied to analyze the dynamical responses of support structure for the extreme and normal states. The results show that the responses of structure for the normal state is bigger than that for the extreme state, and the response results mainly present the traits of wind load.3) The method of S-N curve and Linear accumulative damage method are employed to calculate the fatigue damage for the place of stress concentration by hot pot stress method.Fatigue damage under wind fatigue load and wave fatigue load is calculated respectively, and overplayed by damage coupling method, then got the total fatigue damage.更多还原