Strain estimation for offshore wind turbines with jacket substructures using dual-band modal expansion

Structural fatigue is a design driver for offshore wind turbines (OWT). In particular, the substructures, like jackets, are strongly affected by fatigue. Monitoring the fatigue progression in the welds is vital for the maintenance and a potential lifetime extension. However, inspections of critical locations are costly due to the limited accessibility of the mostly submerged jacket. Considering the high number of potentially critical welds, it is regarded as economically unfeasible to equip all fatigue hot spots with sensors. Thus, an indirect method to monitor the fatigue progress of the structure and point out critical locations is desirable. For a consistent support of ongoing maintenance, it has to yield reliable results for varying operational and environmental conditions. This paper applies a virtual sensing approach to jacket substructures. From a small set of sensors on the tower, fatigue at every desired location of the jacket is estimated using dual-band modal expansion. Simulations using the OC4 jacket design are performed to show potentials and limitations of the method. Namely fatigue progress on leg welds of K-joints is predicted with high accuracy over a wide range of load cases. However, some difficulties in fatigue prediction of X-joints due to the occurrence of local modes and limitations in the extrapolation of wave loading have to be resolved in future work.     

舰用燃气轮机RMS参数体系研究

根据舰用燃气轮机的任务需求和使用环境特点,综合RMS参数体系需要考虑的因素,按定量参数和定性要求,提出了舰用燃气轮机RMS参数体系,并给出了定量参数的含义以及计算公式.     

汽轮发电机异常振动原因分析

汽轮发电机的异常振动是发电厂最为常见故障。分析由于汽轮发电机转子不对称及热效应导致汽轮发电机产生振动的原因，并对发电机转子工作异常现象进行分析。最后，结合工程实例对某电厂大修后开机过程中异常振动故障进行分析，为发电机工频振动诊断提供分析判断的思路和方法。     

电力电子与绿色能源

介绍了绿色能源的概念,以风力发电为重点介绍了电力电子技术在绿色能源发展中的应用以及分布式发电在绿色能源系统方面的应用.     

不同方法对南黄海重现波高计算值的影响

采用SWAN波浪模型对江苏南黄海地区1979~2018年共40 a的波况进行模拟及验证,将模拟结果与实测资料进行比对,吻合良好。百年重现波高分布通过基于年极值和月极值的广义极值分布函数(GEV)和超阈值取值方法(POT)的广义帕累托分布模型(GP)计算得出。计算结果表明,不同方法的计算结果在辐射沙洲北部地区差别最大,采用月极值所得重现波高偏小,采用年极值计算的重现波高在辐射沙洲南北外围地区最大,其余地区则以POT方法为大值。在分别采用不同数据长度计算重现波高的试验中得出,取月极值的GEV分布计算结果对时间跨度的改变不敏感,而取年极值受之影响最大,POT方法介于两者之间。     

Crack growth direction effects on corrosion-fatigue behaviour of offshore wind turbine steel weldments

In this study corrosion-fatigue tests have been conducted on fracture mechanics specimens extracted from an S355 G10+M structural steel welded plate. The tests have been performed on compact tension specimens with the crack tip located in the heat affected zone. The corrosion-fatigue test results from this study have been compared with the data available on the base metal as well as air tests on the same material. Moreover, the obtained results have been compared with the corrosion-fatigue data available in the literature on a wide range of steels and also the fatigue trends for welded joints in free-corrosion condition recommended in the BS7910 Standard. The effect of the specimen orientation, with respect to the weld region, is also examined in this study and it has been found that higher corrosion-fatigue crack growth rates are generally observed in the tests with 0° orientation. The results have also shown that the corrosive environment has significant effects on the fatigue crack growth acceleration at the beginning of the tests; however, as the crack propagates, the environmental damage effect on crack growth behaviour becomes less pronounced. The results presented in this study are discussed in terms of improvement in the structural integrity assessment of offshore wind turbine monopiles.     

关于辐流式二沉池设计计算方法的探讨

针对辐流式二沉池设计资料中存在的相关问题,从平面设计要点和竖向设计要点两方面分别对辐流式二沉池中设计流量的选定、沉淀池表面积计算、进出水口、污泥区容积计算,以及有效水深、池边水深和总池高计算等进行了探讨,并对刮(吸)泥设备和配水井的设计要点进行了相关说明.同时结合工程实践,优化平面设计参数和竖向设计参数,合理选择刮(吸)泥设备和配水井等辅助设施,能为相关技术人员提供一定的参考和借鉴意义.     

三体船侧体布局及型线优化设计研究

采用分层次优化,首先以总阻力最小为优化目标对某三体船侧体横向和纵向的相对位置进行了优化研究,得到阻力性能最优的三体船侧体布局方案;然后基于侧体最优布局,进行型线优化,最终完成三体船的侧体布局和型线的序列优化。结果表明,所采用的三体船侧体布局及型线优化方法具有可行性,可为三体船船型设计提供参考依据。     

燃燃共同运行功率均衡控制策略研究

采用模块化,变比热的方法在labview平台上建立了燃气轮机动态模型,结合电机扭矩控制实现了燃气轮机特性的模拟。设计了燃燃联合运行负荷平均分配的控制策略,并进行了燃燃联合动力共同带负载的半物理仿真试验,试验结果证实采用本文设计的控制策略能实现负荷平均分配,动态过程比较稳定,设计的控制策略能基本满足要求。     

新型波浪潮流耦合发电轮机的研究

为解决海上偏远而分散的小功率用电设施的供电问题,探究潮流能与波浪能耦合发电的可行性,满足耦合发电轮机在耐久性、初级高效获能以及低成本和安全性等方面的要求,设计了一种新型波浪潮流耦合发电轮机。该发电轮机的主体结构由复合式导流罩、叶片轮机、固定式尾舵、发电机和浮子五部分组成,本文详细阐述了该发电轮机的机械设计过程及其结构优化设计思路,并针对叶片轮机进行了水槽性能试验分析。分析结果验证了该装置设计的合理性与科学性。