应用形状记忆合金的桥梁结构振动控制研究及发展

简要介绍了形状记忆合金（SMA）材料的本构关系及其显著特性。总结了桥梁结构在地震和风振作用下的灾害，以及SMA驱动器和阻尼器在桥梁结构隔震及减震应用上的研究现状，展望了SMA在桥梁结构尤其是在大跨度斜拉桥和悬索桥结构抗震风振动控制中的应用前景，指出了基于SMA材料的桥梁结构振动控制研究中亟待解决的一些关键技术。     

一种新型SMA阻尼器的试验研究

在对NiTi形状记忆合金（SMA）的力学性能试验研究的基础上,设计了一种新型SMA阻尼器,根据形状记忆合金丝的超弹性分段线性恢复力模型建立了阻尼器的理论模型,并通过阻尼器的性能试验研究验证了理论模型的正确性,试验结果表明这种阻尼器具有较好的耗能能力。     

一种新型变形可恢复SMA阻尼器力学性能的研究

利用形状记忆合金（Shape Memory Alloy,简称"SMA"）丝材的超弹性与复位弹簧特性,开发出一种新型变形可恢复SMA阻尼器,以增强其变形可恢复的能力。同时,为了解决SMA丝材在实际工程中锚固难的问题,提出了一种新型可调节夹具,不仅解决了SMA丝材的不易锚固问题,而且增强了调节预应变的能力。对所提出的新型SMA阻尼器进行了循环加载试验研究和数值仿真分析,探讨不同加载频率及位移幅值对其力学性能的影响,建立了恢复力模型。结果表明:新型SMA阻尼器在循环荷载作用下滞回性能稳定,具有良好的耗能性能;内置弹簧对新型SMA阻尼器变形可恢复能力有较大帮助。基于所建立恢复力模型的数值模拟结果与试验结果符合情况很好,验证了阻尼器恢复力力模型的正确性。     

一种放大位移型SMA阻尼器的减震控制分析

利用形状记忆合金(SMA)材料的超弹性,本文提出了一种放大位移型SMA阻尼器,建立了装有该阻尼器的框架有限元模型并对该框架的地震反应实施了模拟减震控制。分不安装阻尼器、安装不放大位移阻尼器和安装放大2倍层间位移阻尼器三种工况,输入El Centro和Taft地震动,对比研究了阻尼器的减震控制效果。分析结果表明:(1)放大位移型SMA阻尼器的控制效果优于不放大位移型SMA阻尼器;(2)该放大位移型SMA阻尼器对位移的控制效果优于对加速度的控制效果。     

X形和三角形SMA板式阻尼器的阻尼力模型

本文利用形状记忆合金（Shape Memory Alloy，简称SMA）分段线性化本构关系，推导了X形和三角形SMA板式阻尼器的阻尼力滞回模型。首先，给出了SMA分段线性化本构关系。然后，根据经典力学理论推导建立了SMA板式阻尼器的阻尼力模型。最后，通过一个算例给出了SMA板式阻尼器的阻尼力滞回曲线，结果表明，其滞回曲线在T＞Af时为“小旗帜”形状；而且，在弹性加载、马氏体相变阶段和卸载至逆相变开始前的规律与钢板阻尼器的线性强化模型相同；逆相变开始后，横截面上应力分布发生间断，阻尼力曲线接近直线。     

SMA-压电半主动混合阻尼器减震控制分析

将形状记忆合金（Shape memory alloy,简称"SMA"）与压电摩擦阻尼器复合设计了一种半主动混合阻尼器,对SMA丝进行了材性试验,分析了循环圈数、加载速率和应变幅值对SMA丝力学性能的影响。基于试验数据,以速度方向和应变值作为神经元输入,建立了SMA的BP神经网络本构模型,并利用T-S模糊逻辑求解压电陶瓷驱动器输出电压,对1个2层的钢框架结构进行了无控、SMA被动控制和混合控制MATLAB仿真分析。结果表明:SMA的BP网络模型预测的应力误差大多集中在20 MPa以内,且误差较大点主要集中在加载的初始段和卸载的结束段等数值较小的点,BP神经网络能够较好地预测SMA丝的本构曲线。相比SMA被动控制,混合阻尼器可以更加有效地降低结构的动力反应。     

超弹性形状记忆合金螺旋弹簧恢复力的数值模拟

形状记忆合金(SMAs)在土木工程被动控制领域的研究近年来得到了极大的关注。研究人员已经提出了多种含有SMA丝的隔震器和阻尼器,大尺寸SMA超弹性螺旋弹簧是一种可输出较大位移的阻尼器。由于以往在结构防震减灾领域有关SMA螺旋弹簧力学性能的研究较少,因此在Liang和Rogers提出的SMA应力-应变本构模型的基础上,针对SMA螺旋弹簧恢复力特性建立了一种便于工程应用的新型宏观模型,并利用MATLAB程序进行了数值模拟以验证所提出模型的适用性和正确性。研究结果表明:SMA螺旋弹簧具有较好的复位和耗能能力;同时,根据该宏观模型得到的数值模拟结果与其他学者的试验研究结果吻合较好。总的来看,数值模拟方法可较准确描述超弹性弹簧的力学行为,且方便在现有常规结构软件中实现。     

考虑阻尼器极限状态的耗能减震体系 斜拉桥抗震性能分析

在大震或特大震下,黏滞阻尼器可能因某个极限状态的出现而发生破坏。现有在斜拉桥上设置黏滞阻尼器的研究多集中在阻尼器的参数优化上,很少考虑到阻尼器失效对斜拉桥抗震性能的影响。针对这一问题,以某三塔斜拉桥为背景,利用OpenSees平台建立斜拉桥有限元模型和可以考虑承载力及行程极限的黏滞阻尼器模型;分析黏滞阻尼器的阻尼系数和阻尼指数对斜拉桥地震响应的影响,确定阻尼器参数的取值;对不安装阻尼器、安装不考虑极限状态及考虑极限状态阻尼器等多种工况的斜拉桥进行非线性时程分析,对比各工况斜拉桥的地震响应。分析结果表明,在大震下,考虑极限状态阻尼器的耗能能力及减震效果将显著降低;不考虑阻尼器达到极限状态后失效的情况将高估耗能减震设计斜拉桥的抗震能力。     

SMA复合摩擦阻尼器性能的试验研究

利用形状记忆合金(SMA)的超弹性效应及高阻尼性能,结合传统Pall摩擦型阻尼器的特点,提出了一种SMA复合摩擦阻尼器。在建立阻尼器力学分析模型的基础上,对SMA复合摩擦阻尼器的性能进行了试验研究,分析了位移幅值、加载频率等对阻尼器的等效刚度、单位循环耗能和等效阻尼比的影响,并与理论分析结果进行了对比。研究表明,SMA复合摩擦阻尼器在加卸载循环下会形成比较稳定的滞回曲线,表明这种阻尼器具有良好的耗能能力。     

大跨度斜拉桥阻尼器参数分析

以某大跨度斜拉桥实际工程为依托,研究大跨度斜拉桥线性粘滞阻尼器参数的不同选取对该桥抗震性能的影响。通过线性动力时程分析对线性粘滞阻尼器在大跨度斜拉桥中阻尼系数C进行参数敏感性分析,并与该桥在未设置线性粘滞阻尼器状态下的地震响应进行比较分析。结果表明:斜拉桥纵向设置粘滞阻尼器后,通过调节粘滞阻尼器的参数能有效降低结构在地震作用下关键部位的相对位移;可以有效的控制大跨度斜拉桥纵向位移,但是在高频区,竖向位移放大约为23%;同时也改善了结构构件的地震力响应并为同类工程粘滞阻尼器应用中的参数研究提供参考。     

Structural vibration control by shape memory alloy damper

A damper device based on shape memory alloy (SMA) wires is developed for structural control implementation. The design procedures of the SMA damper are presented. As a case study, eight such SMA dampers are installed in a frame structure to verify the effectiveness of the damper devices. Experimental results show that vibration decay of the SMA damper controlled frame is much faster than that of the uncontrolled frame. The finite‐element method is adopted to conduct the free and forced vibration analysis of the controlled and uncontrolled frame. The experimental and numerical results illustrate that the developed SMA dampers are very effective in reducing structural response and have great potential for use as efficient energy dissipation devices with the advantages of good control of force and no lifetime limits, etc. Copyright © 2003 John Wiley & Sons, Ltd.     

新型SMA耗能器及结构地震反应控制试验研究

利用NiTi合金丝的超弹性性能，本文提出了两种新型SMA被动耗能器，分别称之为拉伸型SMA耗能器和剪刀型SMA耗能器。通过对耗能器的构造设计，安装在耗能器中的NiTi丝始终处于受拉状态，避免了合金丝在结构振动过程中受压屈曲。文中阐述了拉伸型SMA耗能器和剪刀型SMA耗能器的构造及工作原理，并将其安装在模型结构上进行了地震模拟振动台试验，验证了新型SMA耗能器的减振效果。     

安装形状记忆合金阻尼器的剪力墙结构抗震性能分析

为减轻钢筋混凝土剪力墙连梁的地震后永久性损伤,同时保持连梁的耗能机制,本文提出在剪力墙连梁中安装新型形状记忆合金(Shape Memory Alloy,简称SMA)阻尼器,并研究该阻尼器对剪力墙结构地震响应的减震效果。通过一幢12层剪力墙结构地震反应的时程分析,研究了SMA阻尼器的附加刚度比和屈服位移比两项特征参数对结构地震反应控制效果的影响规律。计算分析结果表明,当附加刚度比为0.04～0.05,屈服位移比为0.4～0.5时,可以获得较好的减震效果。     

Hybrid seismic protection of cable‐stayed bridges

This paper proposes a hybrid control strategy combining passive and semi‐active control systems for seismic protection of cable‐stayed bridges. The efficacy of this control strategy is verified by examining the ASCE first‐generation benchmark problem for a seismically excited cable‐stayed bridge, which employs a three‐dimensional linearized evaluation bridge model as a testbed structure. Herein, conventional lead–rubber bearings are introduced as base isolation devices, and semi‐active dampers (e.g., variable orifice damper, controllable fluid damper, etc.) are considered as supplemental damping devices. For the semi‐active dampers, a clipped‐optimal control algorithm, shown to perform well in previous studies involving controllable dampers, is considered. Because the semi‐active damper is a controllable energy‐dissipation device that cannot add mechanical energy to the structural system, the proposed hybrid control strategy is fail‐safe in that the bounded‐input, bounded‐output stability of the controlled structure is guaranteed. Numerical simulation results show that the performance of the proposed hybrid control strategy is quite effective in protecting seismically excited cable‐stayed bridges. Copyright © 2004 John Wiley & Sons, Ltd.     

附加黏弹性阻尼与金属阻尼耗能的自复位墙结构抗震性能对比分析

相对传统结构,自复位墙结构在地震作用下具有更大的变形能力且几乎无残余位移,但其耗能能力较弱,需采用附加阻尼来增加整体耗能.目前,金属阻尼器已广泛用于自复位墙结构,其可显著减小结构大震下的地震响应,但小震下的位移和加速度减震效果不佳.因此,将小变形下即可耗能的黏弹性阻尼器应用于自复位墙结构中.设计一幢10层自复位墙结构,分别采用黏弹性阻尼器和 U 型金属阻尼器作为附加耗能构件,通过弹塑性时程分析对比采用两种耗能机制的结构地震响应.结果表明,黏弹性阻尼器可显著减小自复位墙结构在小震下的位移和加速度响应;U 型金属阻尼器在中震下开始耗能,在大震和巨震下,其减震效果会超越黏弹性阻尼器.因此,为进一步优化自复位墙结构在不同水准地震作用下的抗震性能,建议结合阻尼器的特点进行合理设计.     

Fuzzy logic control of bridge structures using intelligent semi-active seismic isolation systems

Passive supplemental damping in a seismically isolated structure provides the necessary energy dissipation to limit the isolation system displacement. However, damper forces can become quite large as the passive damping level is increased, resulting in the requirement to transfer large forces at the damper connections to the structure which may be particularly difficult to accommodate in retrofit applications. One method to limit the level of damping force while simultaneously controlling the isolation system displacement is to utilize an intelligent hybrid isolation system containing semi-active dampers in which the damping coeffic ient can be modulated. The effectiveness of such a hybrid seismic isolation system for earthquake hazard mitigation is investigated in this paper. The system is examined through an analytical and computational study of the seismic response of a bridge structure containing a hybrid isolation system consisting of elastomeric bearings and semi-active dampers. Control algorithms for operation of the semi-active dampers are developed based on fuzzy logic control theory. Practical limits on the response of the isolation system are considered and utilized in the evaluation of the control algorithms. The results of the study show that both passive and semi-active hybrid seismic isolation systems consisting of combined base isolation bearings and supplemental energy dissipation devices can be beneficial in reducing the seismic response of structures. These hybrid systems may prevent or significantly reduce structural damage during a seismic event. Furthermore, it is shown that intelligent semi-active seismic isolation systems are capable of controlling the peak deck displacement of bridges, and thus reducing the required length of expansion joints, while simultaneously limiting peak damper forces. Copyright © 1999 John Wiley & Sons, Ltd.     

Design of yielding metallic and friction dampers for optimal seismic performance

This paper deals with the optimal design of yielding metallic dampers and friction dampers together as they both have similar design characteristics and parameters. Ample tests and analytical studies have confirmed the effectiveness of these energy dissipation devices for seismic response control and protection of building structures. Since these devices are strongly non‐linear with several parameters controlling their behaviour, their current design procedures are usually cumbersome and not optimal. In this paper, a methodology is presented to determine the optimal design parameters for the devices installed at different locations in a building for a desired performance objective. For a yielding metallic damper, the design parameters of interest are the device yield level, device stiffness, and brace stiffness. For a friction device, the parameters are the slip load level and brace stiffness. Since the devices and the structures installed with these devices behave in a highly non‐linearly manner, and thus must be evaluated by a step‐by‐step time history approach, the genetic algorithm is used to obtain the globally optimal solution. This optimal search approach allows an unusual flexibility in the choice of performance objectives. For demonstration purposes, several sets of numerical examples of optimal damper designs with different performance objectives are presented. Copyright © 2003 John Wiley & Sons, Ltd.     

在振动台模型试验中黏滞阻尼器的设计方法

通过有限元分析,计算出原型结构中黏滞阻尼器的合理参数,然后利用阻尼力相似原则,对原型结构中黏滞阻尼器参数进行相似比运算,转化为模型结构中的黏滞阻尼器参数.运用该方法,在连续梁桥纵向消能减震振动台试验中设计模型黏滞阻尼器,从试验结果来看,黏滞阻尼器发挥了良好的消能减震效果.