基于应力概率分布的管道可靠性分析方法研究

管道是工程结构中非常重要的结构之一,研究管道的可靠性具有重要的理论意义与应用价值。工程结构受本身材料,几何尺寸以及加载等不确定因素的影响,在实际工作中可能会因强度不够而失效。可靠性方法是研究这些因素对结构强度影响的有效手段之一。可靠度则从强度层面表征了结构在诸多不确定因素的影响下能够正常工作的能力。通过对管道在内压作用下的应力分析,得出了管道的可靠度,基于应力概率分布给出了一种模拟管道可靠性的有效的方法。以管道的内径、外径、压力载荷等参数为随机输入变量,选用蒙特卡罗方法对管道的可靠性进行分析,得出了应力的概率分布特征,以及这些随机参数对管道可靠度的影响程度。

海上风机单桩基础疲劳损伤计算方法

为提高海上风机基础疲劳损伤计算的准确性,评价不同计算方法的适用性和影响,以海上风机单桩基础为例进行疲劳评价,建立全时域的动力分析模型和基于功率谱密度函数的频域疲劳损伤计算流程,研究气动阻尼比取值、风与波浪联合作用、应力幅概率分布模型对基础疲劳损伤的影响.结果表明:基础疲劳损伤受气动阻尼比影响突出,风致疲劳损伤对气动阻尼比的敏感性大于浪致疲劳损伤;由于风与波浪联合作用对基础的疲劳损伤有较大影响,简单叠加风致疲劳损伤和浪致疲劳损伤得到的结果较风与波浪联合作用时偏小;确定合适的应力幅概率分布模型十分必要,频域法中采用Dirlik模型得到的风致疲劳损伤和采用快速傅里叶逆变换(IFFT)的浪致疲劳损伤分别与时域法的结果相近,但叠加的总疲劳损伤小于风与波浪联合作用时的总疲劳损伤.

Research and Application of Probability Distribution of Wind Power Fluctuation Characteristics

The fluctuation characteristics is the inherent property of wind power.Through analysis of a large number of wind t＇anns based on measured data,we find it describes the best probability distribution of wind power fluctuation for the mixed Gauss distribution of two components,and try to carry out the physical interpretation of two components.Further discussion is between the probability distribution of fluctuating wind power time difference and whole relationship.It is found that the two have basic similarity.Through comparing the different time level data quantified losses the information of wind power fluctuation,quantitative determination of the degree of impact prediction.We can summarize and understand of wind power fluctuation,constructing instance from the wind farm construction and monitoring prediction two aspect recommendations to overcome the adverse effects of wind power fluctuations on the power grid operation.