风能作为一种绿色可持续发展的可再生能源，已得到世界各国的重视和大力开发。目前，锥筒式钢塔是风力发电支撑结构的主要形式，它主要采用锻造法兰或反向平衡法兰将塔筒节连接而成。然而，锻造法兰螺栓松动是工程应用中不可避免的问题。实际事故统计资料表明，风力发电塔架失效的主要表现形式是：法兰与塔筒环焊缝失效、法兰高强螺栓松动失效及其断裂失效。基于此背景现状，本文结合现场实测与有限元数值分析两种方法对锻造法兰和反向平衡法兰力学性能进行研究，提出法兰高强螺栓健康实时监测技术指标和系统。确保结构持续可靠运行，从而降低风机运行维护成本，提高风力发电行业整体效益。本文主要对以下方面内容进行了研究： 针对锥筒式钢结构风力发电塔架的结构受力特点，基于动态应变测试系统，设计了风力发电塔架疲劳荷载实测方案。通过实测风机特定偏航工况对实测方案的可行性和精度进行了验证，结果表明风力发电塔荷载实测方案可行，实测数据可靠。根据热点应力评定方法，实测了反向平衡法兰各个焊缝推点处的应力幅，计算了各焊缝的热点应力幅值；实测了锻造法兰与塔筒环焊缝的推点处的应力幅，计算了其热点应力幅。实测了反向平衡法兰和锻造法兰高强螺栓的工作应力幅时程。通过实测风电塔架的主要振动形式和固有频率，建立了塔架有限元模态分析的简化模型。 根据DNV规范，建立了反向平衡法兰和锻造法兰焊缝热点应力幅有限元参数化计算模型，通过实测所得相应位置的热点应力幅验证有限元计算模型的准确性。研究分析表明：有限元模型计算结果准确可靠。反向平衡法兰的法兰板与筒壁上焊缝WA是热点应力分析评估的关键部位，实测得到该焊缝热点应力集中系数为1.15。实测焊缝热点应力一点法外推值偏于保守，高于两点法外推值7.70％。反向平衡法兰各焊缝设计热点应力幅值均满足DNV规范要求。由实测锻造法兰与塔筒环焊缝热点应力集中系数为1.21。疲劳设计荷载作用下，锻造法兰与塔筒环焊缝疲劳强度不满足DNV规范要求。 建立反向平衡法兰和锻造法兰高强螺栓群有限元参数化计算模型，并采用实测数据验证了模型的准确性。分析计算高强螺栓松动对反向平衡法兰和锻造法兰高强螺栓群的受力影响规律。在小于1.5倍设计荷载作用下，反向平衡法兰高强螺栓群受拉侧和受压侧应力幅大小相等，符号相反，分布对称。单个螺栓预紧力完全损失对反向平衡法兰螺栓群应力幅影响较小。由于柔性法兰螺栓撬力作用的影响，锻造法兰受拉侧高强螺栓群应力幅随荷载增大而逐渐增大；受压侧应力幅基本保持在一定的增速水平内。锻造法兰单个螺栓完全松动会造成相邻螺栓应力幅的显著增大，增幅最大达40.73％；对较远处螺栓群应力幅影响可以忽略。锻造法兰螺栓群松动会导致法兰连接整体刚度显著下降，受拉侧螺栓群应力幅迅速增大。 根据实测风力发电机组运行期间风速风向资料，统计分析不同风速风向的分布概率。采用Matlab编制雨流法计算统计疲劳荷载分布的计算程序。分析计算不同风速工况下实测疲劳荷载。根据统计分析得到的实测疲劳荷载，基于Palmgren-Miner线性疲劳累积损伤准则，计算关键焊缝和高强螺栓设计年限内的疲劳损伤程度。研究结果表明：反向平衡法兰焊缝和高强螺栓群疲劳性能满足疲劳实际使用要求；锻造法兰与塔筒环焊缝疲劳损伤程度最大；在不考虑螺栓松动的情况下，锻造法兰高强螺栓群满足疲劳要求。 建立反向平衡法兰和锻造法兰健康监测系统，确定监测系统关键参数和监测点布置方式。提出法兰健康状态的监测指标，如螺栓松动监测指标、法兰极限强度监测指标和法兰疲劳监测指标。最后，对响水某3MW海上风电塔法兰连接进行了健康监测分析。结果表明，该法兰健康监测系统数据可靠，运行平稳，可以用于后续风电塔法兰连接健康监测。 关键词：锥筒式钢塔，反向平衡法兰，锻造法兰，现场实测，热点应力法，疲劳，健康监测

 As a type of green sustainable renewable energy, wind energy has received great attention and wide application all over the world. Steel tubular towers, which are the dominant supporting structure for wind converters, are fabricated from steel plates, rolled into short cylinders and welded to a segment suitable for transportation, usually 20～3Om long. On site, the segments are lifted on top of each other and assembled most often by the ring flange connection which includes forged flange connection and reverse balance flange connection. To begin with, engineering problem caused by bolt looseness of forged flange connection and weld fracture shows that more attention should be paid to the flange connection. Then engineering practice and literature investigation reveals that weld fracture between flange and cylinder, looseness and fracture failure of high strength bolts are the main failure modes of wind turbine towers. Under this background, a series of filed measurement and finite element analysis were carried out to study forged flange connection and reverse balanced flange connection. As a result, a health monitoring system on high strength bolt of flange connection was established to ensure safety of wind turbines during operation and to reduce the operation and maintenance cost of wind turbine. The main work of the paper was summarized as follows: The field testing scheme on fatigue performance of tubular steel towers for wind converters applied dynamic strain test system, where the mechanical characteristics of wind turbine tower was taken into consideration. The feasibility and reliability of the testing scheme was verified by means of a specific yawing working condition. The hot spot stress amplitude is deduced from measured value of the thrust point of each weld on both reverse balanced flange and forged flange on the basis of hot spot stress method. At the same time, the working stress amplitude of reverse balancing flange and forged flange high strength bolt is measured. Parametric finite element models aiming at weld hot spot stress amplitude of reverse balance flange and forged flange were established according to DNV standard. The hot spot stress amplitude gained from measurement was compared with that from finite element calculation so as to verify the accuracy of the models. The results showed that the finite element calculation models were accurate and reliable. The upper girth weld between flange plate and cylinder wall namely WA was the most vulnerable detail of reverse balance flange in hot spot stress analysis. And the Stress Concentration Factor (SCF) of hot spot was 1.15 according to measured data. The value of SCF deduced from "one extrapolated point method" was 7.7% higher than that from "two extrapolated points method". So that it was safer to apply "one extrapolated point method". The finite element analysis showed that the results of finite element modeling (FEM) agreed with the DNV standard. The Stress Concentration Factor (SCF) of hot spot was 1.21 according to measured data from forged flange, where the FEM results showed that the fatigue strength of the hot spot didn't satisfy the requirements of DNV specification. The parametric finite element calculation models of the reverse balance flange and forged flange were established. And their accuracy was verified with measured data. The influence that bolts' looseness upon flange's mechanical behavior was investigated. The stress amplitude between tensile side and compressed side of reverse balanced flange (RBF) is symmetrical with uniform distribution under less than 1.5 times of design load in finite element analysis. A single bolt's total preload loss has little effect on the other bolts in RBF. As a consequence of flexible flange connection's prying force, the stress amplitude of forge flange's bolts at tensile side increases with load at an increasing rate; while the stress amplitude of bolts at compressed side increases with load at a steady rate. A single bolt's total preload loss of forged flange can cause a significant increase in adjacent bolt stress amplitude. Forged flange of a single bolt's total preload loss can cause a significant increase in adjacent bolt stress amplitude, the biggest growth up to 40.73%, and the impact on the far bolt group can be ignored. So that bolt looseness can cause a significant reduction in stiffness of flange connection. According to the wind speed and direction data that measured during operation, the statistical analysis about the distribution probability of different wind speed and direction was made. Matlab program was designed to calculate fatigue load according to measured data on the basis of rain flow method. Calculate fatigue cumulative damage and fatigue residual life of crucial welds and bolts based on Miner linear cumulative damage theory and assess their health status. The analysis showed that fatigue performance of welds and bolts in RBF could meet the practical fatigue requirements. And the fatigue performance of welds and bolts in forged flange also could meet the fatigue requirement taking no account of bolt looseness. Establish a health monitoring system to ensure that the working high strength bolts stay in a healthy state and determine monitoring parameters and layout of monitoring points. Put forward technical indicators, like indicators on bolt looseness and ultimate strength load of flange connections and index on fatigue, which indicate that the flange connections are in a heath status. Then apply the health monitoring system to practical engineering program. The results showed that the flange health monitoring system data was reliable, stable operation, can be used for subsequent wind power tower flange connection health monitoring. Key words: tubular steel tower, reverse balance flange (RBF), forged flange (FL), field test, hot spot stress method, fatigue, health monitoring.