为分析在风载-冰载联合作用下海上风力机塔架动力响应非线性特性，以多体动力学仿真开源软件FAST为平台，建立冰-构耦合模型，通过自编程序开发风力机海冰碰撞模块，计算NREL 5 MW风力机在安装不同锥体角度的锥体结构及未安装锥体时受海冰激励作用下的塔顶振动特性，并基于混沌理论，采用相图法及最大Lyapunov指数法从定性与定量两个角度研究了塔顶振动信号的非线性特征。结果表明：未安装锥体及70°锥体结构时，塔顶振动具有明显的混沌特征，最大Lyapunov指数大于零，表现出非周期性的非平稳特征；随着锥体角度的降低，混沌特性减弱并消失，当锥角为40°与50°时，最大Lyapunov指数小于零，混沌特性消失，该结果与塔顶位移时域分析结果相吻合，表明锥体结构能有效减弱塔顶振动，增加风力机稳定性。

In order to analyze the nonlinear characteristics of the dynamic response of the offshore wind turbine’s tower under the combined effect of wind load and ice load,a model coupling the ice and structure is established based on the opensource software FAST,a platform for multibody dynamic simulation.The tower top vibration characteristic of NREL 5 MW wind turbine with cone structure of different cone angle is calculated under ice load,and compared to the one without cone structure.The phase diagram method and the maximum Lyapunov index method are adopted to study the nonlinear characteristics of the vibration signal of tower displacement which is based on Chaos theory.The results show that: the tower top vibration has clear chaotic characteristics for the cases of 70° cone or without cone structure,and their Lyapunov index is greater than zero,indicating nonperiodic and nonstationary characteristics.The chaotic characteristicweakens and disappears as cone angle is reduced.The maximum Lyapunov index is less than zero and chaotic characteristics disappear when cone angle is 40° and 50°.The above results coincide with the time domain analysis of tower top displacement,and the cone angle can effectively reduce the vibration of the tower and improve the stability of wind turbine.

TK83

国家自然科学基金（51676131，51176129）；上海市科学技术委员会项目（13DZ2260900）