海上风力机锥体结构抗振分析

Vibration Analysis of Offshore Wind Turbine with Cone Structure

为降低海冰与海上风力机撞击作用下的结构非线性动力响应,提出锥体结构防振模型并将其安置于风力机与海平面交界处。通过开发海冰载荷计算模块并与风力机多体动力学气动-水动-伺服-弹性仿真软件FAST结合,建立风-冰-结构多物理场耦合下的海上风力机动力学仿真模型。基于Croasdale与Karna方法计算海冰与结构碰撞,对比5组不同锥角下的结构动力学响应,研究锥体结构对海冰碰撞的减振降载效果。结果表明：未安装锥体结构时,海冰载荷、塔顶位移与塔顶加速度的幅值较大,且频率易与风力机发生共振;安装锥体结构后,随着锥角由70°减至40°,动态响应减弱,幅值分别减小79%、71. 8%与30. 8%,且频率均远离风力机固有频率,避免发生共振;塔基剪切力的最大值与标准差也因安装锥体而减小,其中最大值减小26. 9%,标准差减小67. 8%,降低风力机所受的疲劳载荷。

In ordering to reduce nonlinear dynamic response of offshore wind turbine＇s structure when it is impacted by ice, an antivibration model is put forward and it is installed at the interface between the wind turbine and sea level. The mechanical simulation model of offshore wind turbine is established through developing ice load calculation module which is combined with areo-hydro-servo-elastic muhibody dynamic simulation software named FAST. Ice and structure collision is calculated and their structural dy- namic responses are compared under 5 different cone angles based on Croasdale and Karna method to study the vibration reduction effect of cone and ice collision. The results show that： the amplitude of ice force, tower top displacement and acceleration are larger, and their corresponding frequencies are easy to resonate with wind turbine before the cone is installed. The amplitude of ice force, tower top displacement and acceleration is reduced by 79% ,71.8% and 30.8% because the cone angle is reduced from 70° to 40°. At the same time, their corresponding frequencies are different from natural frequency of wind turbine and resonance is avoided. In addition, the fatigue load of wind turbine decreases due to the reductions in the maximum and standard deviation of shear force in tower base that decrease by 26.9% and 67.8% , respectively.