考虑桩基础柔性的固定式海上风力机调谐质量阻尼器参数优化研究

OPTIMIZATION DESIGN OF TUNED MASS DAMPER FOR FIXED BOTTOM OFFSHORE WIND TURBINE WITH PILE FOUNDATION FLEXIBILITIES

将被动调谐质量阻尼器(TMD)应用于单桩基础海上风力机,以降低风、浪联合作用下风力机塔筒结构动力响应。利用等效桩长法模拟桩基础柔性,将该方法引入气动-水动-伺服-弹性-振动控制风力机仿真程序FAST-SC,建立能考虑桩基础柔性影响的固定式风力机-TMD耦合数值仿真模型。同时,选取固定式海上风力机支撑结构一阶弯曲模态为主模态,并将TMD简化为单自由度体系,基于拉格朗日方程建立简化的单桩海上风力机-TMD耦合模型。基于该简化模型,采用响应面法分别对刚性桩基础和柔性桩基础条件下的海上风力机的TMD参数进行优化。将优化的TMD参数代入所建立的能考虑桩基础柔性影响的海上风力机-TMD耦合数值模型中,对比不同风、浪作用下TMD对采用不同桩基础边界条件的海上风力机减振效果的差异。通过对比得出:不同桩基础边界使得单桩基础海上风力机结构频率不同,所得的最优TMD设计参数也不相同,优化设计后的TMD对风、浪联合作用下柔性桩基础海上风力机的减振效果明显优于刚性桩基础。

In the study,the tuned mass damper(TMD)is applied to a monopile offshore wind turbine to reduce the structural dynamic responses under winds and waves.The apparently fixed(AF)model is used to simulate the flexibilities of pile foundation.Then,the boundary conditions of the offshore wind turbine(OWT)and TMD coupled analysis model in FAST-SC are updated,according to the theories of AF model.Meanwhile,in order to perform the optimization design of TMD,the simplified coupled model of OWT and TMD is established based on Lagrange equation.The fist bending mode of the support system of OWT is reserved in the simplified model,and the TMD is simplified as a single degree of freedom system.Sequentially,the optimized TMD parameters are derived using the response surface method.The vibration control effects of TMD are studied based on the coupled responses of OWT under wind and wave loads,and the influence of pile foundation flexibilities on the mitigation effects are proved.It can be seen that the different optimized TMDs are derived owing to the differences of OWT dynamic characteristics caused by pile foundation flexibilities.Further,the more effective reductions of OWT with pile foundation flexibilities using the optimized TMDs are observed.