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By using ABAQUS/Explicit, the dynamic process of an offshore wind turbine（OWT） stricken by a ship of 5000DWT in the front direction is simulated. The OWT is located on a large-scale prestressing bucket foundation constructed by an integrated installation technique. According to the simulation results, under the ship collision, a cer-tain range of plastic zone appears within a local area of arc transition structure of the bucket foundation, and the con-crete plastic zone is seriously damaged. As the stress level of OWT tower is relatively low, the OWT tower is less af-fected. A great inertial force is generated at the top of the OWT tower as the mass of nacelle and blades is up to 400 t. The displacement of the tower is in the opposite direction of the ship collision at the end of 1 s under the action of iner-tial force. There is only a minor damage in the ship bow. Most of the kinetic energy is transformed into the plastic dissipation and absorbed by the arc transition structure of bucket foundation. 相似文献
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《天津大学学报(英文版)》2015,(4)
A series of model experiments of bucket foundations concerning suction installation and negative pressure consolidation in saturated silt were carried out in a cube steel bin at Tianjin University. The experimental results show that the silt inside the bucket has been strengthened by negative pressure, and the strengthening effect decreases with the increase of the distance from the bucket. A three-dimensional numerical model of the experiments was built by means of finite element software ABAQUS with fluid-solid coupling method. The results show that the bearing capacity of the silt inside the bucket foundation increases significantly at the former stage of negative pressure consolidation, while the increasing trend slows down over time. The rotation centers of the bucket foundation and the inner soil region tend to be closer to each other based on the consolidation. The bearing capacity of the bucket foundation is improved effectively with the increase of soil strength. The effects of negative pressure consolidation on the bearing capacity of bucket foundation were also illustrated by an actual offshore wind power project case. 相似文献
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An integrated finite element model(FEM)of offshore wind tower-foundation-soil is established by ABAQUS, where a large-scale composite bucket foundation with seven compartments inside is applied to supporting the upper wind tower. The dynamic response of the structure-foundation system is studied under three seismic waves with the same peak ground acceleration of 0.035g. It can be seen that the dynamic response increases at the beginning with the structure height, then it decreases because the structural damping increases due to the mass effect of the upper wind turbine generator system. It is shown that the anti-liquefaction capacity of the soil inside and underneath the foundation is improved owing to the high overburden pressure of the upper structure and the constraint effect of the bucket skirt and subdivisions. Moreover, the liquefaction resistance of the soil inside the middle compartment is improved to a higher degree than that inside the side compartments. 相似文献
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Cover-bearing-type bucket foundation for offshore wind turbines has been paid more and more attention due to its low cost and great bearing capacity. In order to ensure the cover-bearing mode, the muddy soil inside the bucket foundation should be reinforced by some soil consolidation methods, such as negative pressure and electro-osmosis. Firstly, tests were conducted to obtain the reasonable current density. Meanwhile, to improve the electro-osmotic speed and effectiveness, other factors such as intermittent power and layout of electrode, were also studied in the tests. Then, the soil reinforcing tests by negative pressure combined with electro-osmosis were performed for the muddy soil consolidation inside the bucket foundation. The results showed that soil reinforcement by negative pressure was quicker and more obvious during the early phase, and electro-osmotic method can affect more range of soil by rational arrangement of electrodes. Compared with negative pressure, the electro-osmotic method was a continuous and relatively slow process of reinforcement, which was complementary to the negative pressure method. The voltage value of electro-osmosis had little effect on the muddy soil reinforcement inside the bucket foundation, and 1.5 A was chosen as the most reasonable current value for scale model testing in the electro-osmotic method. 相似文献
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张兴兆 《青岛大学师范学院学报》2008,25(2):31-37
魏晋南北朝是一个海上交通大发展的时期,北方的近海水运形成了一些新的重要海港。北方近海航线有所开辟与延展,江左-辽东航线与渤海海域航线上的水运颇为繁忙。南方与辽东的来往多有赖于近海航线,中原政权对辽东的经略及南北政权的海上军事攻守都利用了北方近海水运。 相似文献
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The large-scale bucket foundation with 30 m in diameter and 6 m in height was used as the foundation of wind turbine.The wide-shallow foundation is different from the traditional bucket foundation with... 相似文献
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The platform with bucket foundations can penetrate and migrate by underpressure/positive pressure technique caused by pumping water out/in the bucket. However, the construction process of bucket foundations cannot be clearly observed and effectively controlled due to the special nature of sea environment. By using an advanced simulation development tool of Multigen Creator, the visual construction simulation program for the platform with bucket foundations was developed to set up the virtual reality system with interaction control and observation in every view angle based on the secondary development technology of Vega platform. The application results show that the method is feasible and effective by simulating the whole construction process for the platform with four bucket foundations. 相似文献
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《天津大学学报(英文版)》2017,(5)
The composite bucket foundation(CBF) is a new kind of foundation which has been applied in the offshore wind industry. A reasonable connection pattern between the tower and the CBF top cover is crucial for load transmissions from the superstructure. Therefore, it is essential to choose an optimum structure type for the transition section. The line type and the arc transition section models were established by ABAQUS, and the internal forces of cross section were extracted along the height direction. Specifically, the force transfer mechanism for different types of the transition sections was investigated comparatively with monotonic as well as composite loadings. The results show that the curved transition structure exhibits the better mechanical characteristics under the monotonic and composite loadings, and the reason can be illustrated that its specific arc-shape structure can effectively convert the tremendous bending moment from the turbine tower into the limited tensile and compressive stresses downwards, without the occurrence of force concentration. 相似文献
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The key in the force transmission between the tower and the foundation for offshore wind turbines is to transfer the large moment and horizontal loads.The finite element model of a large-scale prestres... 相似文献
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A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study. 相似文献
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利用sinumerik 810D数控系统构建了Jsit-siemens 810教学实验平台,根据需求进行电气设计、硬件配置、系统配置和整体的安装调试,并增加了外设模拟,以实现模拟仿真,可用于学校的教学与培训;多次的理论论证和实际修改及应用表明,Jsit-siemens 810教学实验平台达到了预设的要求。 相似文献
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JIANG Zhi-chao DOI Yasuaki ZHANG Shu-you 《浙江大学学报(A卷英文版)》2007,8(9):1414-1421
Straight Darrieus wind turbine has attractive characteristics such as the ability to accept wind from random direction and easy installation and maintenance. But its aerodynamic performance is very complicated,especially for the existence of dynamic stall. How to get better aerodynamic performance arouses lots of interests in the design procedure of a straight Darrieus wind turbine. In this paper,mainly the effects of number of blades and tip speed ratio are discussed. Based on the numerical investigation,an assumed asymmetric straight Darrieus wind turbine is proposed to improve the averaged power coefficient. As to the numerical method,the flow around the turbine is simulated by solving the 2D unsteady Navier-Stokes equation combined with continuous equation. The time marching method on a body-fitted coordinate system based on MAC (Marker-and-Cell) method is used. O-type grid is generated for the whole calculation domain. The characteristics of tangential and normal force are discussed related with dynamic stall of the blade. Averaged power coefficient per period of rotating is calculated to evaluate the eligibility of the turbine. 相似文献
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Suction foundations have been deployed in the last three decades in a growing number of offshore developments, for bottom-fixed and floating structures, in shallow and deep waters, many of them successfully. Suction foundations, traditionally used as anchors and jacket foundations in the oil and gas industry, are now also used in the offshore renewable (wind) industry, e.g. for monopods, tripods, and jackets. When technically feasible, suction foundations are often cheaper than pile foundations. Additionally, their installation is relatively noise-free and, by applying overpressure, they can be removed during decommissioning. This paper focuses on the more complex design issues and some pitfalls related to suction foundation design. Additionally design practices and recommendations for suction caisson design, including installation and extraction feasibility, foundation resistance, settlements and response in sand, clay and layered soil profiles, will be presented for basic understanding. 相似文献
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《天津大学学报(英文版)》2017,(6)
The development of offshore wind farms in deep water favors floating wind turbine designs, but floating horizontal axis wind turbines are facing the challenge of high cost of energy(CoE). The development of innovative designs to reduce the CoE is thus desirable, such as floating vertical axis wind turbines(VAWTs). This study demonstrates the characteristics of aerodynamic loads and load effects of a two-bladed floating VAWT supported by a semi-submersible platform. Fully coupled simulations are performed using the time-domain aero-hydro-servo-elastic code SIMO-RIFLEX-AC. It is found that thrust, lateral force, and aerodynamic torque vary considerably and periodically with the rotor azimuth angle. However, the variation in the generator torque can be alleviated to some extent by the control strategy applied. Moreover, the variations of platform motions and tensions in the mooring lines are strongly influenced by turbulent winds, whereas those of tower-base bending moments are not. The towerbase bending moments exhibit notable two-per-revolution(2P) response characteristics. 相似文献
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操惊雷 《黄冈职业技术学院学报》2005,7(3):84-86
现代城域网是一个全业务的网络,为满足宽带业务以及网络速度的需要,采用了长途传输网络的DWDM技术,该系统成本高,维护费用大。CWDM技术的出现,为城域网建设提供了低成本、高效率的传输平台。本文从城域网应用粗波分复用技术几个方面作了简要介绍。 相似文献
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温艳艳 《天津职业院校联合学报》2013,15(5):37-40
太阳能光伏系统的设计包括:容量设计、电气设计、机械结构设计、热力设计、安全设计、可靠性设计、包装运输设计、安装调试运行设计以及维修检测设计等。设计是对拟建工项目的实施,在技术和经济等方面所进行的全面而详尽的部署,是基本建设构思的具体落实化,是把先进技术和科研成果引入建设的渠道,是整个工程的决定性环节,是组织实施的依据等,是工程项目建设中的重要阶段。 相似文献
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Design of offshore wind power foundation with multi-bucket 总被引：1，自引：0，他引：1
Three- and four-bucket offshore wind power foundations with a new form of force-transferring structure are proposed in this paper, and the integrated finite element model of foundation-soil-transition structure is established by using ABAQUS. The carrying capacity of the proposed foundations is studied under vertical load, horizontal load and bending moment. It can be seen that the vertical bearing capacity of multi-bucket foundation can be roughly estimated by the vertical bearing capacity of single-bucket; the horizontal bearing capacity of the three-bucket foundation scheme is controlled by displacement, while that of the four-bucket foundation scheme is controlled by the internal forces of soils. Moreover, the carrying capacity is provided by the overall structure formed by multi-bucket before soil failure. Compared with the conventional single-bucket foundation, there are mainly tension and pressure that are applied to the multi-bucket foundation, so that the carrying capacity of the foundation can be fully utilized. The probability of soil failure can be well reduced with the proposed multi-bucket foundation, and the stress transmission of force-transferring structure is more consistent through steel beams with variable cross-section. 相似文献