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1.
The worldwide demand for renewable energy is increasing rapidly. Wind energy appears as a good solution to copy with the energy shortage situation. In recent years, offshore wind energy has become an attractive option due to the increasing development of the multitudinous offshore wind turbines. Because of the unstable vibration for the barge-type offshore wind turbine in various maritime conditions, an ameliorative method incorporating a tuned mass damper (TMD) in offshore wind turbine platform is proposed to demonstrate the improvement of the structural dynamic performance in this investigation. The Lagrange's equations are applied to establish a limited degree-of-freedom (DOF) mathematical model for the barge-type offshore wind turbine. The objective function is defined as the suppression rate of the standard deviation for the tower top deflection due to the fact that the tower top deflection is essential to the tower bottom fatigue loads, then frequency tuning method and genetic algorithm (GA) are employed respectively to obtain the globally optimum TMD design parameters using this objective function. Numerical simulations based on FAST have been carried out in typical load cases in order to evaluate the effect of the passive control system. The need to prevent the platform mass increasing obviously has become apparent due to the installation of a heavy TMD in the barge-type platform. In this case, partial ballast is substituted for the equal mass of the tuned mass damper, and then the vibration mitigation is simulated in five typical load cases. The results show that the passive control can improve the dynamic responses of the barge-type wind turbine by placing a TMD in the floating platform. Through replacing partial ballast with a uniform mass of the tuned mass damper, a significant reduction of the dynamic response is also observed in simulation results for the barge-type floating structure. 相似文献
2.
高层建筑地震反应最优多重TLD控制 总被引：3，自引：1，他引：3
本文以坑层建筑地震反应进行了最优多重ＴＬＤ（ＭＴＬＤ）ｓ控制研究。文中阐述了ＴＬＤ系统的工作原理笔ＭＴＬＤｓ系统的参数；建立了多层结构－ＴＭＬＤｓ系统耦联体系的运动方程；分析了ＭＴＬＤｓ系统的参数对在谐波作用下多层结构动力反应的影响以及各参数之间的关系。 相似文献
3.
The problems of ice-induced vibration have been noticed and concerned since the 1960s, but it has not been well resolved. One reason is that the dynamic interaction between ice and structure is so complicated that practical ice force model has not been developed. The recent full-scale tests conducted on jacket platforms in the Bohai Sea presented that ice could cause intense vibrations which endanger the facilities on the deck and make discomfort for the crew. In this paper, the strategy of mitigation of ice-induced offshore structure vibration is discussed. Based on field observations and understanding of the interaction between ice and structure, the absorption mitigation method to suppress ice-induced vibration is presented. The numerical simulations were conducted for a simplified model of platform attached with a Tuned Mass Danlper （TMD） under ice force function and ice force time history. The simulation results show that TMD can fa- vorably reduce ice-induced vibrations, therefore, it can be considered to be an alternative approach to utilize. Finally, the application possibilities of utilizing TMDs on other miniature offshore structures in ice-covered areas of marginal oil fields are discussed. 相似文献
4.
This paper investigates the dynamic behavior and the seismic effectiveness of a non‐conventional Tuned Mass Damper (TMD) with large mass ratio. Compared with conventional TMD, the device mass is increased up to be comparable with the mass of the structure to be protected, aiming at a better control performance. In order to avoid the introduction of an excessive additional weight, masses already present on the structure are converted into tuned masses, retaining structural or architectural functions beyond the mere control function. A reduced order model is introduced for design purposes and the optimal design of a large mass ratio TMD for seismic applications is then formulated. The design method is specifically developed to implement High‐Damping Rubber Bearings (HDRB) to connect the device mass to the main structure, taking advantage of combining stiffness and noticeable damping characteristics. Ground acceleration is modeled as a Gaussian random process with white noise power spectral density. A numerical searching technique is used to obtain the optimal design parameter, the frequency ratio alpha, which minimizes the root‐mean‐square displacement response of the main structure. The study finally comprises shaking table tests on a 1:5 scale model under a wide selection of accelerograms, both artificial and natural, to assess the seismic effectiveness of the proposed large mass ratio TMD. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
5.
Optimal design and performance evaluation of systems with Tuned Mass Damper Inerter (TMDI) 
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下载免费PDF全文 The paper concerns the optimal design and performance evaluation of a Tuned Mass Damper Inerter (TMDI) to reduce dynamic vibrations. The system exploits properties of the inerter, a two‐terminal mechanical device able to produce a force proportional to the relative acceleration between terminals, with the ability of generating an apparent mass even two orders of magnitude greater than its own physical mass. A primary single‐degree‐of‐freedom structure is equipped with a classical linear Tuned Mass Damper (TMD), the secondary structure, whose mass is connected to the ground via an inerter. The optimal design of the TMDI is conducted by assuming a white noise process as base input and utilizing three different design methodologies: displacement minimization, acceleration minimization and maximization of the ratio between the energy dissipated in the secondary system and the total input energy. Optimal results obtained with the different methodologies are carried out and compared. Two limit cases are also considered when the inerter is not contemplated: conventional and non‐conventional TMDs, characterized by a low and a large mass ratio, respectively. The TMDI performance is evaluated and compared with conventional and non‐conventional TMDs; moreover, its robustness is assessed with a sensitivity analysis varying the design parameters. Attention is focused not exclusively on the primary structure response but also on the secondary one. Finally, the effectiveness of the optimally designed TMDI is evaluated having considered earthquake base excitation. Results demonstrate the effectiveness of TMDI systems for dynamic response reduction with superior performances and robustness than classical TMDs. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
6.
This paper investigates the optimized parameters for tuned mass dampers (TMDs) to decrease the earthquake vibrations of tall buildings; involving soil–structure interaction (SSI) effects. The time domain analysis based on Newmark method is employed in this study. To illustrate the results, Tabas and Kobe earthquakes data are applied to the model, and ant colony optimization (ACO) method is utilized to obtain the best parameters for TMD. The TMD mass, damping coefficient and spring stiffness are assumed as design variables, and the objective is to reduce both the maximum displacement and acceleration of stories. It is shown that how the ACO can be effectively applied to design the optimum TMD device. It is also indicated that the soil type greatly affects the TMD optimized parameters and the time response of structures. This study helps the researchers to better understanding of earthquake vibrations, and leads the designers to achieve the optimized TMD for high-rise buildings. 相似文献
7.
调频液体阻尼器(TLD)的等效力学模型研究 总被引：5，自引：0，他引：5
本文根据流体力学理论,建立了圆柱形ＴＬＤ中晃动液体的势流场,并从液体晃动的动力效应等效原则出发,导出了晃动液体的等效力学模型,并阐明其适用范围。文量计算的结果表明,在工程应用中,仅用ＴＬＤ的一阶晃动等效力学模型就能满足工程需要。 相似文献
8.
近年来,各地纷纷兴建大型火车站房,这类建筑中的楼盖大多为大跨、轻质和低阻尼结构,本文基于人体舒适度考虑,对这些大跨楼盖进行振动舒适度的分析。首先,建立某大型火车站房的整体有限元模型,研究这类建筑中大跨楼盖的振动特性;随后,对楼盖在各种不利工况人群荷载作用下的振动舒适度进行分析;最后,在已有研究的基础上,提出了大跨楼盖多重调谐质量阻尼器（Multiple Tuned Mass Dampers,简称MTMD）减振设计方法。结果表明,利用该方法设计MTMD减振系统,可以有效地控制大跨楼盖的竖向振动,各工况下的平均减振率可达34%,从而使结构在使用时满足人体舒适度的要求。 相似文献
9.
调频液体阻尼器(TLD)作为一种被动耗能减震装置,由于涉及到两种形态的物质之间的相互作用,真实准确地掌握调谐液体阻尼器的减震特性显得尤为困难,因此建立更加精确的流固耦合模型,进而探讨带调谐液体阻尼器结构的抗震性能是一件非常有意义的工作.本文利用ADINA有限元分析软件分别建立了结构动力学模型和流体动力学模型,并利用其流一固耦合分析模块,对此耦合模型进行瞬态分析,模拟计算结果与试验简化模型的结果具有较好的一致性.在此基础上通过动力时程分析得到了调谐液体阻尼器流场的变化特性,并结合流场特性考查了频率比、地震动、质量比这三个因素对带调频液体阻尼器结构抗震性能的影响,对比分析表明频率比对TLD的减振性能的影响最为显著,最后给出了TLD的设计建议. 相似文献
10.
Liquid moment amplitude assessment in sloshing type problems with smooth particle hydrodynamics 总被引：5，自引：0，他引：5
A. Souto-Iglesias L. Delorme L. Prez-Rojas S. Abril-Prez 《Ocean Engineering》2006,33(11-12):1462-1484
Sloshing moment amplitudes in a rectangular tank for a wide range of rolling frequencies are investigated both experimentally and numerically. In a previous paper, Souto et al. [2004. Simulation of anti-roll tanks and sloshing type problems with smoothed particle hydrodynamics. Ocean Eng. 31 (8–9), 1169–1192] numerical results obtained with a 3-D Smooth Particle Hydrodynamics (SPH) formulation were presented. These only corresponded to the phase lag between the tank motion and the liquid response moment. This paper is aimed at improving those results by obtaining accurate values for the moment amplitudes. We present the corrections with respect to the aforementioned implementation that focus on the time integration scheme and on the treatment of the boundary conditions. In addition better quality experimental results are presented. 相似文献