In order to predict the lifetime of products appropriately with long lifetime and high reliability,the accelerated degradation testing(ADT)has been proposed.Composite wind turbine blade is one of the most important co...In order to predict the lifetime of products appropriately with long lifetime and high reliability,the accelerated degradation testing(ADT)has been proposed.Composite wind turbine blade is one of the most important components in wind turbine system.Its fatigue cycle is very long in practice.A full-scale fatigue testing is usually used to verify the design of a new blade.In general,the full-scale fatigue testing of blade is accelerated on the basis of the damage equivalent principle.During the full-scale fatigue test ing,blade is subjected to higher testing load than normal operat ing conditions;consequently,the performance degradation of the blade is hastened over time.The full-scale fatigue testing of blade is regarded as a special ADT.According to the fatigue failure criterion,we choose blade stiffness as the characteristic quantity of the blade performance,and propose an accelerated model(AM)for blade on the basis of the theories of ADT.Then,degradation path of the blade stiffness is modeled by using Gamma process.Finally,the lifet ime prediction of full-scale megawatt(MW)blade is conducted by combining the proposed AM and blade stiffness degradation model.The prediction results prove the reasonability and validity of this study.This can supply a new approach to predict the lifetime of the full-scale MW blade.展开更多
A damage detection method for complicated beam-like structures is proposed based on the subsection strain energy method （SSEM）, and its applicability condition is introduced. For a beam with the continuously varying...A damage detection method for complicated beam-like structures is proposed based on the subsection strain energy method （SSEM）, and its applicability condition is introduced. For a beam with the continuously varying fiexural stiffness and an edge crack, the SSEM is used to detect the crack location effectively by numerical modal shapes. As a complicated beam, the glass fiber-reinforced composite model of a wind turbine blade is studied based on an experimental modal analysis. The SSEM is used to calculate the damage index from the measured modal parameters and locate the damage position in the blade model successfully. The results indicate that the SSEM based on the modal shapes can be used to detect the damages in complicated beams or beam-like structures for engineering applications.展开更多
为了研究大型变桨轴承滚道表面接触受力,首先,利用三维软件UG建立变桨轴承、叶根及轮毂三维模型,使用有限元分析软件(finite element analysis,FEA)提取各零件的刚度矩阵,通过导入Ansys中从而建立整机模型;其次,使用Link单元模拟钢球,...为了研究大型变桨轴承滚道表面接触受力,首先,利用三维软件UG建立变桨轴承、叶根及轮毂三维模型,使用有限元分析软件(finite element analysis,FEA)提取各零件的刚度矩阵,通过导入Ansys中从而建立整机模型;其次,使用Link单元模拟钢球,通过提取各模拟钢球所受到的外力得到滚道与钢球之间的压力,从而进行滚道接触分析;最后,通过载荷叠加法获取滚道的最大压力,与经典的理论计算公式进行对比,验证了该有限元模型及方法的正确性。该方法为变桨轴承的安全性和可靠性设计提供了理论基础,也为后续变桨轴承的疲劳分析及优化工作提供依据。展开更多
基金the National Natural Science Founda-tion of China(No.51665029)。
文摘In order to predict the lifetime of products appropriately with long lifetime and high reliability,the accelerated degradation testing(ADT)has been proposed.Composite wind turbine blade is one of the most important components in wind turbine system.Its fatigue cycle is very long in practice.A full-scale fatigue testing is usually used to verify the design of a new blade.In general,the full-scale fatigue testing of blade is accelerated on the basis of the damage equivalent principle.During the full-scale fatigue test ing,blade is subjected to higher testing load than normal operat ing conditions;consequently,the performance degradation of the blade is hastened over time.The full-scale fatigue testing of blade is regarded as a special ADT.According to the fatigue failure criterion,we choose blade stiffness as the characteristic quantity of the blade performance,and propose an accelerated model(AM)for blade on the basis of the theories of ADT.Then,degradation path of the blade stiffness is modeled by using Gamma process.Finally,the lifet ime prediction of full-scale megawatt(MW)blade is conducted by combining the proposed AM and blade stiffness degradation model.The prediction results prove the reasonability and validity of this study.This can supply a new approach to predict the lifetime of the full-scale MW blade.
基金supported by the National Basic Research Program of China (973 Program)(No. 2007CB714603)
文摘A damage detection method for complicated beam-like structures is proposed based on the subsection strain energy method （SSEM）, and its applicability condition is introduced. For a beam with the continuously varying fiexural stiffness and an edge crack, the SSEM is used to detect the crack location effectively by numerical modal shapes. As a complicated beam, the glass fiber-reinforced composite model of a wind turbine blade is studied based on an experimental modal analysis. The SSEM is used to calculate the damage index from the measured modal parameters and locate the damage position in the blade model successfully. The results indicate that the SSEM based on the modal shapes can be used to detect the damages in complicated beams or beam-like structures for engineering applications.
文摘为了研究大型变桨轴承滚道表面接触受力,首先,利用三维软件UG建立变桨轴承、叶根及轮毂三维模型,使用有限元分析软件(finite element analysis,FEA)提取各零件的刚度矩阵,通过导入Ansys中从而建立整机模型;其次,使用Link单元模拟钢球,通过提取各模拟钢球所受到的外力得到滚道与钢球之间的压力,从而进行滚道接触分析;最后,通过载荷叠加法获取滚道的最大压力,与经典的理论计算公式进行对比,验证了该有限元模型及方法的正确性。该方法为变桨轴承的安全性和可靠性设计提供了理论基础,也为后续变桨轴承的疲劳分析及优化工作提供依据。
