基于分形特征的海上风力机防护装置设计研究

根据分形理论设计一种分形防护装置，基于非线性动力学理论，采用ANSYS/LS-DYNA模拟5000 t船舶与设有不同阶数防护装置的4 MW海上风力机碰撞过程，分析研究不同阶数防护装置的防护效果。结果表明：较橡胶材料实心防护装置，分形防护装置可有效降低接触力，延长接触时间；分形结构可提高防护装置内能转化能力，促进外层钢壳吸能，并提升橡胶内能耗散；分形防护装置应力峰值更低，高应力区域更广，可使更大面积材料发挥防护作用，有效降低撞深。不同阶数分形结构的抗撞性能与分形孔受撞后变形状况有关，其中一阶分形结构提升防护装置抗撞性能最优。

RESEARCH ON PROTECTION DEVICE OF OFFSHORE WIND TURBINE BASED ON FRACTAL CHARACTERISTICS

With the increasing number of offshore wind farms construction and most of them are in the busy channel, the probability of collision of wind turbines by ships increased extensively. A fractal protection device was designed using the fractal theory in this paper. Based on the nonlinear dynamics theory, ANSYS/LS-DYNA was used to simulate the collision process between a 5000 t ship and a 4 MW offshore wind turbine with different fractal order protection devices. The contact force, energy conversion, stress and collision depth were analyzed. The results show that the first, fractal protective devices can reduce the contact force by 3.93%, and can effectively extend the contact time compared with solid protective devices. In addition, the fractal structure can improve the internal energy conversion ability of the protective device, promote the energy absorption of the outer steel shell, and enhance the internal energy dissipation of rubber. Comparing with the solid one, the fractal protection device has a lower stress peak and a wider high stress zones, which can make more material play a protective role and effectively reduce the impact depth. The anti-collision performance of fractal structure of different order is related to the deformation of fractal hole after collision, and the first order fractal structure has the best protective performance.