Energy Analysis for TMD-Structure Systems Subjected to Impact Loading

This paper investigates the characteristics of reduction of the lateral vibration by use of a Tuned Mass Damper(TMD) for offshore jacket platforms under impact loading. Unlike traditional analysis, the present analysis focnses on theenergy concept of TMD/structure systems. In this study, a time domain is taken. The platform is modeled as a simplifiedsingle-degree-of-freedom (SDOF) system by extraction of the first vibration mode of the structure and the excited force isassumed to be impact loading. The energy dissipation and energy transmission of the structure-TMD system are studied.Finally, an optimized TMD design for the modeled platform is demonstrated based on a new type of cost function - maxi-mum dissipated energy by TMD. Results indicate that TMD control is effective in reducing the standard deviation of thedeck motion but less effective in reducing the maximum response under impact loading.     

Offshore Structural Control Considering Fluid Structure Interaction

1.IntroductionAmong various control devices,Tuned Mass Damper(TMD)has been mostfrequently usedtothecontrol of structural vibration induced by oscillating loads such as earthquakes,winds,and waves.This is due to the fact that it operates without external e…     

X形和三角形钢板阻尼器的阻尼力模型(Ⅰ)--基于双线性本构关系

利用软钢的双线性本构关系，依据经典力学原理推导建立了X形和三角形钢板阻尼器的阻尼力滞回模型。首先，导出了单调加载下钢板阻尼器的力与位移关系及其渐近曲线；其次，对于软钢材料本构关系分别考虑在理想弹塑性和双线性强化模型基础上，推导建立了钢板阻尼器的阻尼力模型；最后，将钢板阻尼器的阻尼力模型及其参数与试验结果进行了比较，验证了理论模型的有效性，并分析了误差存在的原因。     

三种阻尼减振结构抗震性能的对比分析

对设置两种新型摩擦阻尼器(T形芯板摩擦阻尼器和拟粘滞摩擦阻尼器)和粘滞阻尼器的单自由度结构及多层实际工程结构进行了时程分析研究。结果表明，一方面三种阻尼器都能有效地控制结构的反应，另一方面T形芯板摩擦阻尼器的位移控制效果略好于拟粘滞摩擦阻尼器，但是后者的加速度控制效果好于前者。     

不同频率影响下结构减振效果分析

利用MR阻尼器进行结构振动控制已得到广泛应用，并在时程分析中证明了其良好的减振效果。但不同频率地震波输入将对建筑物减振效果产生怎样的影响，减振效果和结构物本身自振频率是怎样的关系，这些是以往的时程分析所不能解决的。从这些问题出发，通过对一在底层安装了一个磁流变阻尼器的十二层结构在不同的地震波滤波工况下减振效果进行分析，得出不同频率输入和减振效果的关系。     

An investigation of tuned liquid dampers equipped with damping screens under 2D excitation

This paper reports on the results of a study conducted on tanks partially filled with water, representing tuned liquid dampers (TLD), subjected to both 1D and 2D horizontal excitations. The sloshing response of the water in the tank is characterized by the free surface motion, the resulting base shear force, and evaluation of the energy dissipated by the sloshing water. A 1D non‐linear flow model capable of simulating a TLD equipped with damping screens is employed to model a 2D TLD. Application of this particular model requires the assumption that the response is decoupled and can be treated as the summation of two independent 1D TLDs. Results from the non‐linear flow model are compared with the 2D experimental shake table test results leading to a validation of the decoupled response assumption. This attractive decoupled response property allows square and rectangular tanks to be used as 2D TLDs, which can simultaneously reduce the dynamic response of a structure in two perpendicular modes of vibration. Copyright © 2005 John Wiley & Sons, Ltd.     

Studies on structural vibration control with MR dampers using μGA

A new approach to reducing the seismic response of spatial structures with magneto-theological （MR） dampers is presented in this paper. The Genetic Algorithm with small populations （μGA） is used to optimize the control for the MR dampers to reduce structural vibration, which is difficult to achieve using classical optimal control. The advantages of μGA are the use of global properties and that fewer conditions are required to obtain the optimal function. Numerical results demonstrate the effectiveness of the proposed method in reducing the seismic response of structures.     

A Hertz contact model with non‐linear damping for pounding simulation

This paper investigates the cogency of various impact models in capturing the seismic pounding response of adjacent structures. The analytical models considered include the contact force‐based linear spring, Kelvin and Hertz models, and the restitution‐based stereomechanical approach. In addition, a contact model based on the Hertz law and using a non‐linear hysteresis damper (Hertzdamp model) is also introduced for pounding simulation. Simple analytical approaches are presented to determine the impact stiffness parameters of the various contact models. Parameter studies are performed using two degree‐of‐freedom linear oscillators to determine the effects of impact modelling strategy, system period ratio, peak ground acceleration (PGA) and energy loss during impact on the system responses. A suite of 27 ground motion records from 13 different earthquakes is used in the analysis. The results indicate that the system displacements from the stereomechanical, Kelvin and Hertzdamp models are similar for a given coefficient of restitution, despite using different impact methodologies. Pounding increases the responses of the stiffer system, especially for highly out‐of‐phase systems. Energy loss during impact is more significant at higher levels of PGA. Based on the findings, the Hertz model provides adequate results at low PGA levels, and the Hertzdamp model is recommended at moderate and high PGA levels. Copyright © 2006 John Wiley & Sons, Ltd.     

框架结构SMA阻尼器被动控制模拟分析

介绍了形状记忆合金(SMA)阻尼器的性能,引入其本构关系,建立其热力学方程。针对所提出的阻尼器及相关参数选择,利用ANSYS进行框架结构中的被动控制模拟。将所得的未加与加入SMA阻尼器下顶层位移进行比较,发现SMA阻尼器可以很好地提高框架结构的抗震性能,并提出进一步研究的方法。     

铅挤压消能支撑框架模型结构试验研究

通过铅挤压消能器的低周反复加载试验,以及安装有铅挤压消能器的钢筋混凝土消能支撑框架模型结构的伪静力试验,主要研究了铅挤压消能器单独受反复荷载时的消能性能以及其在模型结构中所起的消能作用,模型结构的破坏机理和整体消能能力。研究结果表明,铅挤压消能器具有很好的消能能力,在模型结构总耗能中占据了很大的比例,模型结构具有较好的耗散地震能量的能力。