长期水平荷载对单桩式海上风机结构自振频率的影响分析  

Effect of long-term horizontal load on the natural frequency of monopile supported offshore wind turbine structures

作　　者：孙毅龙 许成顺[1] 席仁强[2] 杜修力[1] 豆鹏飞 SUN Yilong;XU Chengshun;XI Renqiang;DU Xiuli;DOU Pengfei(Key Lab of Urban Security and Disaster Engineering,Beijing University of Technology,Beijing 100124,China;School of Mechanical Engineering,Changzhou University,Changzhou 213164,China;Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]常州大学机械工程学院,江苏常州213164 [3]清华大学水利水电工程系,北京100084

出　　处：《振动与冲击》2023年第2期108-115,138,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金优秀青年基金(51722801)。

摘　　要：海上风机结构体系长期经受波浪、风等水平循环荷载的作用,从而引起地基刚度变化,海上风机结构体系属于动力敏感型结构,预测其自振频率的长期变化具有非常重要的工程意义。基于动力运动方程,考虑了桩土相互作用,通过嵌入地基刚度衰减模型考虑长期循环荷载引起的地基刚度变化,建立了单桩式海上风机结构自振频率的简化计算方法,利用实际工程和数值模拟验证了方法的可行性。最后通过开展参数分析,探讨长期循环荷载大小、加载次数对海上风机结构自振频率的影响规律;结果表明,循环荷载的增大、加载次数的增加会导致海上风机结构体系自振频率较小,风机结构体系的自振频率应偏移1P;该方法可以评估长期循环荷载下单桩式海上风机结构自振频率的变化,为近海风机结构自振频率的设计提供参考。Offshore wind turbine structures usually suffer wave, wind and other external lateral cyclic loads. Long-term cyclic loading causes the variation of foundation stiffness. The offshore wind turbine structural system is sensitive to these dynamic cyclic loads, so it is very important to predict the long-term effect of cyclic loading on its natural frequency. A method was developed to analyze the natural frequency of the offshore wind turbine structural system with considering soil-pile interaction and the effect of long-term cyclic loading. The method was based on the kinematic equation of the damped system, considering the long-term effect of cyclic loading on the foundation stiffness by embedding a foundation stiffness degradation model. The method was then validated by engineering data and numerical calculation. Parameter studies were conduct to present the influences of the cyclic loading amplitude, cyclic number and pile diameter on the natural frequency of the offshore wind turbine structural system by using the developed method. The results show that the natural frequency of the offshore wind turbine structural system will decrease with increasing cyclic loading amplitude and cyclic number, and the natural vibration frequency of the fan structural system will be biased towards 1P with increasing the cyclic number. The method can be used to evaluate the natural frequency of monopile supported offshore wind turbine structures under long-term cyclic loading, and provide a reference for the design of the natural frequency of offshore wind turbines.

关 键 词：海上风机 单桩基础 长期循环荷载 自振频率 

分 类 号：TU47[建筑科学—结构工程]