基于线性累计损伤理论的预应力混凝土风电塔架疲劳可靠性及剩余寿命研究

Fatigue reliability and remaining life analysis of prestressed concrete wind turbine towers based on linear cumulative damage rule

基于线性累积损伤准则的理论,对预应力混凝土风电塔架的疲劳可靠性评估进行研究.建立目标结构的有限元分析模型,根据目标结构所在场地模拟出不同风速等级下的随机风荷载时程曲线,采用雨流计数法统计目标结构疲劳关键点的应力幅及其相关的循环次数,根据损伤等效原则将其转化为常幅疲劳应力谱,结合风速分布规律,根据材料的S-N曲线和线性累计损伤准则算出结构的疲劳可靠指标及其剩余寿命.最后以某预应力风电塔架为例,对其进行疲劳可靠性分析,通过施加不同等级的风荷载时程样本,对塔架可能出现的疲劳破坏关键点进行计算,得出该塔架关键点处的疲劳可靠性指标与失效概率,并根据损伤程度评估其剩余寿命,进而可以评定风力发电塔架的安全可靠性.

This paper presents the work on the fatigue reliability analysis of prestressed concrete wind turbine towers based on the linear cumulative damage rule. The finite element model （FEM） of the objective structure is established first, based on which the time history of random wind loading can be simulated according to the site condition of the objective structure. The rain-flow counting method is employed to count the stress amplitude and the number of cycles of the critical points of the targeted structure. According to the damage equivalent principle, it is transformed into the constant amplitude fatigue stress spectrum. Taking into account the distribution of wind speed, the fatigue reliability index of structure and its remai- ning life can be calculated according to the S-N curve of the material and the linear cumulative damage criterion. Finally, based on a prestressed concrete wind turbine tower, the fatigue reliability analysis is carried out by applying different levels of wind load. The key points of the tower that may have fatigue failure are investigated to investigate the fatigue reliability index at the points. The remaining life of each key point is also evaluated, which could provide reference for the safety and reliability assessment of the wind turbine tower.