振动频谱再分析的模糊模式识别法

本文首先讨论工程振动信号频谱再分析技术,针对所存在问题,提出模糊式识别再分析方法,以滚动轴承振动成因研究中的谱分析为例,具体介绍了频谱的峰值频率分布模式,模糊子集及隶属函数的确定,以及综合评判的识别过程,最后给出一具体计算结果。     

连续梁的压电分流阻尼模型

建立具有压电分流阻尼的连续梁的动力学基本方程,推导出适用于各种不同分支电路构型的广义传递函数,并推导出对应于三种不同分支电路的电器元件最优参数表达式。对三种不同分支电路的减振特性进行理论分析和比较。分析结果表明,LR并联和LR串联分支电路可以有效地减小振动幅值,并具有相同的减振效果。在LR-C并联分支电路中,通过附加一个电容,可以减小最优设计时所需的电感值,但是减振效果降低。本文为连续梁的压电分流阻尼系统的减振设计提供了有效的方法。     

LINEAR ACTIVE STRUCTURES AND MODES （ Ⅰ ） — BASIC CONCEPTS AND PROPERTIES

Some basic concepts about the active structures were firstly explained, and the main subjects to study in the field of active structure dynamics were synthesized. For the linear active structures, the annotations on the modes were done in detail. The physical meanings of the right and left eigenvectors were explained. The right eigenvectors are the modal shapes and the modal responses of an active structure depend on the left ones. The adjoint structure of an active structure was defined and the reciprocity theorem was interpreted. For two active structures, which are adjoint to each other and with the reciprocal gain-matrices, the right and left eigenvector are reciprocal The relationship between an active structure and the corresponding passive structure is expressed with the transfer functions, which is employed to resolve the estimation problems.     

Convex-model analysis of the seismic response

I.IntroductionThemaximumresponseofastructureisoftenusedasthebasisfordesigning.Drenick(l968,l97o),Shinozuka(l97O)andmanyotherauthorshaveusedthemaximumresponsetoseismicexcitationasadesigncriterion.Theresponse-spectrumtheoryinseismicdesignisalsobasedonthemax…     

The hybrid control of vibration of thin plate with active constrained damping layer

This paper concerns in the active and passive hybrid control of vibration of the thin plate with Local Active Constrained damping Layer (LACL). The governing equations of system are formulated based on the constitutive equations of elastic, viscoelastic, piezoelectric materials. Galerkin method and GHM method are employed to transform partial differential equations into ordinary ones with a lower dimension. LQR method of classical control theory is used in simulating calculation. Numeral results show that the active and passive hybrid control manner obtained in this paper is a better one for vibration control of the plate. Project supported by the National Science Foundation of China (19632001) and the Research Foundation of Xian Jiaotong University     

随机调幅Rattling系统建模

本文研究了一个随机调幅Ｒａｔｌｉｎｇ系统·代替常用的数值分析方法,采用非高斯截断技术,导出一个由三维平均映射描述的离散的随机模型·实测指出该模型能揭示浑沌随机性质,故更适于用以模拟齿轮箱噪声源     

LINEAR ACTIVE STRUCTURES AND MODES (Ⅰ) —BASIC CONCEPTS AND PROPERTIES

IntroductionThestudyobjectoftheclassicstructuredynamicsispassivestructure .Whencontroldevicesorsmartmaterialareintroducedintoitwiththeapplicationofcontrolfunction ,thepassivestructuresarechangedintotheactivestructures.Theactivestructureisgenerallycalledactivesystem .Withtherapiddevelopmentofadaptivestructures,controlledstructuresandsmartstructures,therewillbemoreandmorekindsoftheactivestructures.Alotofspecialstudyontheactivestructureswillbedevelopedintooneofanewknowledgebranchinthefieldofthes…     

圆柱杆侵彻过程及应力波传播分析

研究了初始侵彻速度为１０００ｍ／ｓ～２０００ｍ／ｓ的圆锥杆对半无限厚水泥靶的垂直侵彻过程及其应力波传播。针对初始侵彻速度范围内的撞击特点，发展了计算撞击力的刚体－流体撞击模型和计算靶体变形的法向膨胀理论。模拟动量定理和功能守恒定律，建立了圆锥杆垂直侵彻半元限厚水泫靶时的动力学模型。结非线性动力学方程的数值解，确定了撞击力。在些基础上，根据牛顿第二定律建立了圆锥杆的波动方程，研究了应力波在圆锥中的传     

一类非线性系统载荷识别的组合迭代法

针对一类非线性系统提出了一种新的载荷识别方法,组合迭代法.该方法通过有限元方法和主动控制方法组合迭代来实现一类非线性系统的载荷识别.首先将非线性系统的有限元模型模态缩减成简化模型,由简化模型组成主动控制的被控对象;然后在选定的控制律下,设计控制调节器,使该系统监测点的响应功率谱密度达到预定谱,从而得到系统激励,即被识别的载荷;最后由非线性有限元响应验证载荷的合理性.对圆锥壳-包带组合系统载荷识别的数值研究表明了组合迭代法的有效性.该方法为导弹、宇宙飞船、航天飞机、火箭等航天航空结构振动试验的载荷识别提供指导作用,将促进航天航空事业的发展.     

主动板的正交性条件

给出主动结构的伴随主动结构定义,将由离散主动结构的基本方程推导出来的互易定理推广应用于连续主动结构,具体研究分布作动和分布测量的主动板.通过引入作动和测量的位置函数,给出线性控制方程和测量方程,推导出用主动板振型和伴随主动板振型表示的模态正交性条件,并用数值模拟实例加以解释.应用这些正交性条件,可将主动板的运动微分方程解耦.