【作者】 田鹏刚；

【导师】 王社良；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2007， 博士

【摘要】 空间钢结构是目前应用最广泛的工程结构形式之一。由于钢材具有轻质高强的特性,截面比较开展纤细,所以常常造成结构发生失稳破坏,并且这种破坏一旦发生,结构将随之坍塌,导致灾难性后果。因此,研究空间钢结构的静/动力稳定问题具有重要的理论意义和实用价值。目前,避免或防止结构失稳的主要方法是增大杆件的截面面积或控制杆件的长细比等,是一种被动的设防方法。为此,本文基于结构控制的思想,提出了应用压电主元杆件进行空间钢结构智能稳定监测与控制的方法,进行了相应的理论和试验研究,主要工作包括:(1)根据压电材料的电力学特性,提出了一种适用于空间钢结构稳定监测与控制的压电主元杆件的构造方法,其主要原理是在普通杆件的适当部位集成压电堆以形成压电主元杆件,并将其集成在结构的关键部位,从而满足承载、监测和驱动的功能要求。(2)以本文提出的压电主元杆件为计算模型,研究了压电主元杆件的静力稳定控制性能,探讨了不同长度比、刚度比以及驱动力等因素对其控制性能的影响,同时还研究了压电主元杆件的动力稳定控制性能,分别考虑了突加荷载、简谐荷载以及地震作用等对其控制性能的影响,提出了相应的静/动力稳定控制理论分析模型。(3)采用自编的Matlab程序,以简谐荷载为例,研究了压电主元杆件考虑机电耦合作用和不考虑机电耦合作用时的动力稳定控制性能,并通过对其前三个主要动力失稳区域的跟踪,探讨了压电堆长度、压电堆夹持力以及外部激励特性等对其动力稳定控制性能的影响,得出了压电主元杆件动力稳定控制性能的一般规律。(4)进行了122根两种不同材料、17种长细比、2种类别的空间结构杆件稳定性能试验,同时进行了相应的理论分析,建立了根据结构构件显式响应进行失稳判别的双参数准则,得到了相应的简化计算公式。此外,还研究了压电主元杆件中压电堆的最优长度和最优位置等,设计、制作了2根试验用压电主元杆件,并进行了相应的稳定控制试验,检验了其静/动力稳定控制效果。(5)根据压电材料的机电耦合效应以及本文提出的失稳判别准则与稳定控制方程等,编写了能够进行波形发生、数据采集、阈值判别和驱动等多功能的Visual Basic程序,并且自主设计开发了能够适用于空间钢结构失稳监测和稳定控制的专用智能控制器,实现了结构状态数据采集与控制的同步进行。(6)根据优化控制理论,研究了空间结构设置压电主元杆件的优化分析理论模型,提出了相应的实用优化设计方法,即最大相对位移法,讨论了最大贡献率的计算方法和步骤以及压电主元杆件的最优设置位置等,并以此为依据设计、制作了2个含压电主元杆件的空间结构模型。(7)考虑压电主元杆件的机电耦合作用和非机电耦合作用,进行了2个空间结构模型无控和有控时的振动台试验,分别输入El-centro地震波和简谐波等,其中地震波激励时的峰值加速度为200gal-1200gal,简谐波激励时的驱动电压放大倍数分别为1倍、10倍、20倍和30倍等,以探讨压电主元杆件的稳定监测/控制规律和效果。(8)以非线性有限元方法为基础,考虑压电主元杆件的机电耦合作用和非机电耦合作用两种情况,分别对空间钢结构试验模型进行了X方向和Y方向,以及X-Y-Z三向同时激励时的动力时程分析,其结果与振动台试验结果吻合较好。(9)根据模型结构的动力时程分析结果,基于B-R准则和本文提出的双参数准则,分别进行了模型结构的动力失稳判别,得出了模型结构有控和无控时的动力失稳临界峰值加速度,计算结果精度较高,说明文中的双参数显式失稳准则判别结果可靠,可供工程应用时参考。更多还原

【Abstract】 Space steel structure is one of the most widely used architectural forms for the time being. Because the steel is of lightweight yet of high strength, and has a slender section, as a result, what causes the failure of this kind of structure is not the lack of strength, but the occurrence of a special state of instability, that is to say the buckling of the structure. Due to the sudden failure of buckling for structure or member, once the buckling develops, the structure will immediately collapse and lead to disastrous consequences. So the research on the dynamic and static stability for space steel structure becomes rather theoretically significant and of practical value.Nowadays the principal methods to prevent buckling of the structure include the increase in area of cross-section and on the control of slenderness ratio, etc, which belong to a kind of passive fortification method. For this reason, based on the thought of control over structure, this paper puts forward a new method, which utilizes the piezoelectric pivot member bar to realize intelligent stability monitoring and control over the space steel structure; meanwhile, in this paper the corresponding theoretical and experimental researches are conducted, and the main work is as following:(1) First of all, according to the basic electro-mechanical behavior of piezoelectric material, this paper deals with details of pivot element bar appropriate to control over the buckling of skeleton steel structure; the bar is laminated from slices of piezoelectric ceramic; it is mechanically tandem and electrically parallel, thus which can realize a requirement for big driving force and displacement, and at the same time reduce the requirement for too high driving voltage. Therefore, both the requirement for bearing capacity of structure can be satisfied, and test and drive of structure can be synchronously implemented.(2) Taking the piezoelectric pivot element bar addressed here as a calculation model, this paper studies the static stability of the pivot element bar, analyzes influences of such factors as different length ratios, stiffness ratios, and driving forces etc, and then obtains laws of numerical relation between them; this paper also investigates the dynamic stability of the pivot element bar, considers the dynamic stability respectively under the action of shock load, simple harmonic load, and random load of earthquake, and furthermore proposes theoretical analysis models corresponding to the control of static and dynamic stability.(3) By the use of self-compiling Matlab program, taking the simple harmonic load as an example, this paper researches behaviors of dynamic stability control in considering and neglecting the electro-mechanical coupling of the pivot element bar, through tracking its former three zones of dynamic buckling, this paper investigates the influence of such factors on behaviors of dynamic stability control as the length of piezoelectric pile, the gripping force of piezoelectric pile and the characteristic of external excitation etc., and also obtains a general law of the behavior of dynamic stability control of the piezoelectric pivot element bar.(4) This paper performs an experimental research on 122 ordinary member bars with 17 slenderness ratios, comprising two different materials, makes a theoretical derivation, thus puts forward a double-parameter criterion of stability break based on explicit responses of the structural members, yields corresponding simplified calculation formulae. Additionally, this paper still studies the optimal length and placement of piezoelectric pile in the pivot element bar, designs and fabricates two piezoelectric pivot element bars for tests; meanwhile, the corresponding tests of stability control are conducted to verify the effectiveness of its static and dynamic stability control.(5) On the basis of the electro-mechanical coupling effect of piezoelectric materials, buckling criterion and stability control equations presented in this paper, the Visual Basic program is compiled, which integrates multifunction including wave generation, data acquisition, threshold judgment and driving function etc. In the meanwhile, the special intelligent controller suitable for the monitoring of buckling and stability control for space steel structure is designed and exploited, and realizes the synchronous data acquisition and control of structure states.(6) According to the theory of optimum control, this paper explores theoretical model of optimum analysis for space structure with the piezoelectric pivot element bars set, advances the corresponding practical optimum design method, that is the method of the maximum relative displacement, discusses the calculation method of the maximum contribution rate and procedures as well as the optimal placement of the piezoelectric pivot element bars; besides, this paper designs and fabricates 2 space structure models with the piezoelectric pivot element bar.(7) Considering the electro-mechanical and non-electro-mechanical coupling effect, this paper conducts shaking table tests on 2 space structures with or without control. Respectively input El-centro earthquake wave and simple harmonic wave etc. Here, the peak acceleration of earthquake excitation is 200gal-1200gal, the magnification times of driving voltage at the excitation of simple harmonic wave is respectively 1, 10, 20 and 30 so as to investigate stability monitoring/ stability control law and effectiveness of the piezoelectric pivot element bar.(8) Based on the nonlinear finite element method, considering the electro-mechanical and the non-electro-mechanical effect of the piezoelectric pivot element bar, this paper performs a dynamic time-history analysis under the excitation of X, Y and X-Y-Z axis. The analysis results are in a good agreement with experimental results of shaking table.(9) In accordance with the results of dynamic time-history analysis for the model structures, based on B-R criterion and the double-parameter criterion advanced here, this paper discriminates the dynamic stability break of model structures respectively, obtains critical peak accelerations of model structures with and without control. The calculation results have a high precision, which demonstrates the reliability of discriminant results obtained by the use of explicit double-parameter buckling criterion and these results can provide reference for engineering application.更多还原