1.《复合离心机电液伺服振动台系统及其智能融合控制》(贺云波)

摘要：由于独立进行离心加速度试验和振动试验不能完全反映设备的复合工作状况，近年来离心和振动复合环境试验越来越得到学术和工程领域的重视，复合离心机振动台系统的研究状况已经成为衡量国家科技发展的一个重要因素，具有承载能力强、结实耐用、易于实现高精度力和位移控制等优点的复合电液台也越来越多地应用在航空航天、地震模拟和土工技术等领域中。鉴于国内在这一研究领域的不足，本文对复合电液台进行了开创性的研究，为以后研制大型的复合电液台作技术上的准备。研究工作如下： 1. 讨论了复合电液台顺臂安装和垂臂安装的具体结构实现和每种安装方式需要解决的问题。进一步对两种安装方式进行了建模，得出此阀控缸的顺臂模型与普通阀控缸模型的区别之处在于参数的不确定性、液压缸固有频率和阻尼比的可变化性、以及扰动中含有未被完全平衡的离心力而表现出的复杂性。 2. 对液压管道、电液伺服阀和液压缸及负载进行了离心力环境影响情况分析，推导出离心力引起的管道内油压变化与油液密度、离心转速和管道长度的理论关系；分析了离心力对双喷嘴挡板阀和单喷嘴挡板阀所受的液动力大小和转动力矩大小和液动力刚度的影响情况，首次开创性地通过理论分析与实验验证得出伺服阀零偏电流与离心加速度呈比例关系的结论；激振缸及负载的轴向离心力需要大小相等方向相反的力来平衡，文中提出了采用离心力平衡缸的解决方案。 3. 模糊控制器具有鲁棒性和不基于控制对象模型的优点，文中用来控制此复杂的电液振动台系统。为提高模糊控制器的稳态控制精度和消除抖动现象，提出了多调整因子模糊控制器结构，并将多调整因子作为全局优化对象，采用混合遗传算法和模拟退火算法（BGASAA）进行优化。采用专家知识设计了专家在线协调器，用以在线调整模糊控制器的量化因子和比例因子，仿真和实验结果显示此控制器基本消除了简单模糊控制器控制精度不高和易抖动的不足之处，控制效果明显提高。在仿真过程中将未被完全平衡的离心力作为干扰力的一部分。 4. 采用了模糊推理神经网络控制器结构，使模糊控制系统借助神经网络结构完成推理过程，具有了自学习和自适应功能。采用BGASAA算法优化Gauss型函数的中心值和宽度，用BP最速下降算法在线调整网络权值。仿真过程中将系统模型的非线性特征转移为参数的时变，并将未完全平衡的离心力作为扰动力加以考虑。采用此模糊推理神经网络控制器和离在线优化学习算法进行了实验验证，仿真和实验结果均满足精度要求。 5. 最后进行了轻基础实验。通过与地面实基础实验对比，得出离心机臂轻基础对电液伺服振动台系统的影响结果。

n          文中的创新点：(1)顺臂安装、垂臂安装的异同，及顺臂安装对阀控缸的影响；(2)离心力对液压系统的影响<双喷嘴挡板阀、管道压力、离心力液压缸的设计>；(3)模糊控制器的设计；(4)设计模糊推理神经网络控制器结构；(5)研究了轻基础对电液振动台系统的影响。

n          作者的相关文章：E:论文库贺云波

 

 

 

 

 

 

 

 

 

 

2.《离心力-振动复合力学环境的模拟与控制》(董龙雷)

摘要：复合力学环境模拟试验是力学环境试验的重要发展方向,在工程实践中受到越来越广泛的重视,特别是离心力-振动复合力学环境模拟试验在航空、航天领域具有广泛的工程应用背景.目前,复合力学环境模拟试验在模拟理论、模拟方法、系统特性及控制实现等方面都有待研究与开发.从力学角度看,复合力学环境模拟试验系统是一个复杂的多体动力学系统;从控制角度看,它又是一个多参数的具有严重不确定性和非线性特征的系统.离心力-振动复合力学环境模拟与控制研究具有重要的理论及工程应用价值.论文以国家自然科学基金"复合动态环境的仿真与控制"及中国工程物理研究院院外基金"离心机上液压振动台的控制系统研究"为依托,以中国工程物理研究院的结构力学环境试验为背景,对复合力学环境的模拟与控制进行了基础性问题的研究.论文主要研究内容如下:(1)从相似工程学的角度进行了力学试验环境模拟理论的研究,提出了力学环境效应一致性准则,并应用相似性定理分析了离心力-振动复合力学环境下结构的相似准则及试验条件.(2)应用多体动力学理论建立了复合力学环境模拟试验系统的动力学模型.引入高斯最小拘束原理,建立了离心力-振动复合力学环境模拟试验系统的动力学方程,反映了振动台与离心机机臂的运动耦合以及系统的非线性动力学特性,并分析了振动台的运动刚度特性.(3)系统研究了电液伺服系统在离心力场中的力学特性,分析了离心力场中油液传输特性,并提出离心液压的概念.(4)建立了一套数值仿真分析方法.利用改进的Wilson-9法进行非线性动力学方程的数值分析,并给出了数值计算稳定性的条件.(5)研究了一类离散非线性系统的模糊自适应控制方法,应用Lyapunov稳定性定理给出了模糊辨识及模糊控制的稳定性条件.(6)复合力学环境试验系统的实验研究.

n          文中的创新点：(1)力学环境的相似性原理<力学环境模拟实验的基础>；(2)离心振动实验系统的动力学模型<振动台与转臂的运动耦合、非线性动力学、振动台的运动刚度>；(3)液压振动系统在离心力场下的动态特性，提出了离心液压的概念；(4)仿真实验；(5)模糊自适应算法；(6)实验研究。

n          作者的相关文章：E:论文库董龙雷

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.《Development of Dynamic Capability for Geotechnical Centrifuge Model Studies-为土工离心模型研究配备动态能力》(Paul Van Laak)  

Abstract:This thesis describes an assemblage of facilities, equipment and experimental techniques which have been developed at Rensselaer Polytechnic Institute (RPI) to aid in small-scale physical modeling of geotechnical systems. The goal of this work has been to achieve an experimental capability for studying earthquake phenomena in geotechnical systems under controlled laboratory conditions. Toward this end, as part of this thesis a geotechnical centrifuge facility has been developed and configured for measuring the dynamic behavior of small-scale models of soil-and soil-structure systems. A 100 g-ton centrifuge, built to RPI specification, has been installed in a newly constructed underground enclosure that augmented RPI’s existing geotechnical laboratory. Two servo-hydraulic shakers for applying base input motion to containers of soil have been designed and fabricated as part of this thesis. These shakers have been optimized to provide the high-force, high-frequency shaking required to adequately model seismic loading in the elevated-g environment on the centrifuge. The bearing system which supports the shaken load has been carefully designed to constrain the shaking motion to one horizontal direction minimizing uncontrollable transverse components. Finally, a flexible-walled, stacked ring model container has been designed, constructed and tested. This laminar box is designed to provide suitable boundary conditions for modeling a column of soil in the free-field subjected to horizontal input motion applied at the base. In addition, the container has been specially designed to permit large localized lateral strains, making it useful for studies in lateral spreading and flow failures due to liquefaction.

This equipment has been designed to operate with a specific model of centrifuge, the Acutronic 665. However, it can be utilized with any centrifuge having sufficient payload capacity. In addition, the equipment is scaleable, and similar dynamic capabilities can be developed for geotechnical centrifuges of virtually any size.

n          单词列表：

1.       assemblage [ə'semblidʒ]: n. 装配；集合；聚集；集会；集合物；聚集的物或人

2.       geotechnical [dʒi:əu'teknikəl] adj. 土工技术的

3.       enclosure [in'kləuʒə] n. 附件；围墙；围场

4.       transverse [trænsˈvɜ:s] adj. 横向的；横断的；贯轴的 n. 横断面；贯轴；横肌

n          文章的创新点：(1)制造了两台液压振动台；

 

 

 

 

 

n          论文跟踪：

 

 

 

 

 

 

 

4.《Development of an earthquake motion simulator for centrifuge testing and the dynamic response of a model sand embankment-用于离心实验的地震运动模拟器的建立及沙堤岸模型的动态响应》(Ketcham)

Abstract:For embankments constructed with zones of saturated and cohesionless soil, the phenomenon called liquefaction is a potential cause of failure. In order to study the influence that earthquake-induced liquefaction has on embankment response, engineers have relied on observations from rare embankment failures, laboratory tests of soil elements, and theoretical studies. Recently the geotechnical centrifuge has been used in physical modeling experiments to study the liquefaction of embankments during earthquakes. It is now recognized as an important tool for such work.

Centrifuge model studies of embankment response during earthquakes are linked to the capability to simulate the excitation of earthquakes, and various efforts have been made to develop such capabilities for existing centrifuges. This study included the development of an electrohydraulic earthquake motion simulator for a 15 g-ton centrifuge. The development included the design of the simulator, the application of a correction algorithm for achieving scaled earthquake motions, and the characterization of the response of the simulator and the response of the centrifuge arm and basket to the simulator motions.

The development of the earthquake motion simulator represents a successful application of hydraulic control system technology for centrifuge applications. The response of the centrifuge arm and basket to the earthquake motion simulator excitation was characterized by low and high frequency resonance phenomena.

The study further included experiments conducted on a model embankment comprised of loose, water-saturated sand. The embankment experiments were ambient vibration and earthquake base-excitation experiments. The objectives of the experiments were the identification of the fundamental shear mode of the model embankment from the low level test data, and the measurement of the failure response of a model embankment for which a contractive response would result from the earthquake excitation.

The low level response of the model sand embankment was dominated by a fundamental shear response mode consistent with measurements of full scale embankment response. The response of the embankment to a simulated earthquake was a contractive response characterized by rapid buildup of excess pore pressure immediately following the first shock of the base excitation, and corresponding loss of shearing resistance. The embankment failed by lateral spreading.

n          单词列表：

1.          cohesionless [kəu'hi:ʒənli:s]: adj. 非粘结性的

2.          liquefaction [.likwi'fækʃən] n. 液化,溶解

3.          embankment [im'bæŋkmənt] n. 堤防,筑堤

4.          resonance ['rezənəns] n. 共鸣，共振，反响

5.          ambient ['æmbiənt] adj. 周围的，氛围的 n. 环境

6.          contractive [kən'træktiv] adj.  收缩的， 有收缩性的

n          文章的创新点：(1)电液振动台的建造(振动台的设计，校正算法的应用，振动台、离心机臂和吊篮在运动模拟时的响应特点)；(2)离心机臂和吊篮在地震运动下的响应表现为在低频和高频的共振现象。(3)完成了实验，分析了实验结果。

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