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1.
本文针对多层厂房内的安装机床及设备,提出了同时考虑机床弹性及安装基础动态特性的非刚性隔振系统的建模方法,应用子结构传递矩阵法推导了该复杂隔振系统的传递率,并给出相应的功率流解析表达式。为进一步研究柔性基础上安装机床和设备的振动噪声控制提供了理论依据,并可推广应用于弹性基础上的双层隔振系统。  相似文献   

2.
以功率流隔振理论对双层隔振系统中的参数变化对基础振动的影响进行研究。将双层隔振系统简化为多个具有四端参数的理想机械系统的双层隔振系统功率流隔振模型,推导出各机械系统的四端参数,通过编写的双层隔振系统Mat lab应用程序,计算并绘制了隔振设备质量、隔振器刚度以及中间质量块质量等参数对传递基础功率流和振动速度的影响,研究表明:参数的改变对功率流变化影响较小;改变上层隔振器刚度和中间小质量块的质量可以调节二阶共振峰值的频率,提高二阶峰值后频带的隔振效果。  相似文献   

3.
双层主动隔振系统的动力学研究   总被引:11,自引:2,他引:9  
研究了在消极隔振情况下,双层主动隔振系统在其主动隔振执行器的3种不同安装方式的动力学特性,分析了主动控制力与被动隔振器参数之间的关系。研究结果表明,对于双层主动隔振系统,隔离中低频振动时,主动隔振执行器安装于中间质量与基础之间的隔振性能最好,安装于隔振对象与中间质量之间的隔振性能最差;隔离高频振动时,主动隔振执行器安装于隔振对象与中间质量之间或仅作用于隔振对象时的隔振性能均较好,但主动隔振执行器安装于中间质量与基础之间所需的主动隔振控制力也不大。  相似文献   

4.
多自由度隔振系统在受迫振动下的动力学特性是目前工程机械振动控制研究的热点。基于广义拉格朗日方程和矢量环方法求解出多自由度隔振系统的运动微分方程,揭示了影响运动的关键参数变量;通过ADAMS/Vibration模块研究了弹簧刚度以及阻尼系数对多自由度隔振系统频谱特性的具体影响,具有重要的工程意义。  相似文献   

5.
为了提高船舶动力设备单层隔振系统的隔振性能,研究半主动磁流变(magnetorheological,简称MR)阻尼器和基础质量对系统传递特性的影响规律,采用通过试验验证的改进的Bingham模型描述MR阻尼器的力学特性,建立考虑基础质量影响的二自由度无约束隔振系统的动力学模型。通过平均法得到了隔振系统主共振时的解析解,并通过数值方法验证了理论解的正确性。以力传递率为评价指标,研究了半主动隔振系统主要参数对系统主共振的影响。结果表明:基础质量增加可降低系统的固有频率及隔振区域的减振效果;MR阻尼器控制力和零力速度的增加可提升隔振性能;MR阻尼器的阻尼增加可提高共振区域的隔振效果,但降低了隔振区域的隔振效果。  相似文献   

6.
本文针对多层厂房内的安装机床及设备,提出了同时考虑机床弹性及安装基础动态特性的非刚性隔振系统的建模方法,应用子结构传递矩阵法推导了该复杂隔振系统的传递率,并给出了相应的功率流解析表达式,为进一步研究柔性基础上安装机床和设备的振动噪声控制提供了理论依据,并可推广应用于弹性基础上的双层隔振系统。  相似文献   

7.
罗煜峰 《电子机械工程》2007,23(1):14-16,19
使用状态空间法,将隔振系统的微分方程组转化为状态空间方程,使用MATLAB/Simulink模块可方便求解多自由度有阻尼隔振系统的固有频率和隔振系数。  相似文献   

8.
针对高层建筑加压水泵的振动控制问题,建立了具有两个自由度的单层隔振模型,通过动力学微分方程推导了垂向偏心激振力作用下系统的动态响应,以4排8个减振器的非对称布置为例,分析了激振力偏心距和隔振器参数变化对基础传递率的影响,为多自由度耦合隔振系统的优化设计提供理论依据。  相似文献   

9.
根据现有主减反共振隔振和主动控制理论,设计新型直升机主减隔振原理样机模型。随着直升机工作频率的改变,隔振系统识别频率的变化,自动调节隔振器质量块位置,使系统始终有隔振效果。以直升机原理样机为对象,加入基于神经网络的控制方法,对实验对象进行动力学特性标定,获得质量块位置与工作频率之间的关系。研究频率跟踪算法,将神经网络和频率跟踪算法两者结合,编制出可以采集信号,识别频率的LabVIEW程序。实验结果证明,新型主减隔振系统隔振效果和控制效果符合预期,可以为直升机主减的振动主动控制系统设计提供一定的指导。  相似文献   

10.
以梁单元作为研究基础,引入型函数与广义坐标建立单元运动微分方程。通过坐标转换矩阵与协调矩阵结合拉格朗日方程组集得到系统的运动微分方程。以弹性四杆机构作为研究对象,对其铰接点与系统内任意一点的弹性位移进行了动力学建模与分析,为后续机构的可靠性计算奠定基础。  相似文献   

11.
Simple linear Kelvin or Maxwell models cannot predict adequately the response of many practical systems to vibration excitation. A more realistic model consisting of a mass between two preloaded non-linear (cubic elasticity springs) and restrained by a Coulomb and viscous damper is proposed. A harmonic motion solution, satisfying “on the average” the non-linear differential equation of motion of the model is developed whereby equations for frequency response curves are obtained. Expressions for relative and absolute transmissibility as well as their values at resonance are developed, these are shown to properly reduce to the respective exact expressions of a Kelvin model and friction damped linear spring. Although the model is intended mainly for quantitative design in packaging engineering problems, it is suitable for studying general vibration isolation problems as well.  相似文献   

12.
罗煜峰 《机械》2007,34(8):13-16
使用状态空间法,将背架式隔振系统的微分方程组转化为状态空间方程,使用MATLAB/Simulink模块可方便求解背架式隔振系统的固有频率和隔振系数,为背架式隔振器系统设计、选用提供理论依据.  相似文献   

13.
基于Matlab的六自由度隔振系统计算   总被引:2,自引:0,他引:2  
采用Matlab程序技术,简化了底部安装隔振器的六自由度隔振系统的固有频率计算工作量.通过将隔振系统的微分方程组转化为状态空间方程,使用Matlab/Simulink模块可方便求解隔振系统的隔振系数曲线.  相似文献   

14.
Low-frequency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been developed. However, few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility. An active low-frequency vertical vibration isolation system based on an earlier instrument, the Super Spring, is designed and implemented. The system, which is simple and compact, consists of two stages: a parallelogram-shaped linkage to ensure vertical motion, and a simple spring-mass system. The theoretical analysis of the vibration isolation system is presented, including terms erroneously ignored before. By carefully choosing the mechanical parameters according to the above analysis and using feedback control, the resonance frequency of the system is reduced from 2.3 to 0.03 Hz, a reduction by a factor of more than 75. The vibration isolation system is installed as an inertial reference in an absolute gravimeter, where it improved the scatter of the absolute gravity values by a factor of 5. The experimental results verifies the improved performance of the isolation system, making it particularly suitable for precision experiments. The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems. An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed, providing fundamental guidelines for vibration isolator design and assembling.  相似文献   

15.
为了避免和减轻由过大隔震层位移引起的损害,对基础隔震框架结构装设调频液柱阻尼器(tuned liquid column damper,简称TLCD)后混合系统的减振效果进行研究。建立了单层和多层混合控制系统在地震作用下的运动方程,采用TLCD-结构体系转化为调频质量阻尼器(tuned mass damper,简称TMD)-结构体系的等效方法,利用TMD参数优化公式,得到单个TLCD初始设计参数,并采用状态空间方程得到多个TLCD最优设计参数。通过对某8层基础隔震结构进行模拟,证明了该理论设计方法的合理性。该混合结构不仅可以减小隔震层位移和加速度,而且对上部结构位移和加速度反应都能更有效的控制。  相似文献   

16.
综合运用统计能量分析(SEA)理论和功率流方法,建立了多方向激励作用下的侧向悬挂双层隔振系统的统计能量分析模型,对其功率流传递率进行了仿真分析,同时进行了侧向悬挂双层隔振系统的功率流实验,测量了其在多方向激励作用下的功率流传递率,将统计能量仿真计算结果与功率流实验结果进行了对比,结果表明两者的功率流传递率在中高频段基本一致,传递到基础的侧向功率流大于垂向功率流,侧向振动在侧向双层隔振系统中不能被忽略。  相似文献   

17.
The modeling of a hybrid passive damping system is presented for suppressing the multiple vibration modes of beams in this paper. This hybrid passive damping system consists of a constrained layer damping and a resonant shunt circuit. In a passive mechanical constrained layer damping, a viscoelastic layer, which is sandwiched between a host structure and a cover layer, is used to suppress vibration amplitudes in the high frequency range. A passive electrical damping is designed for targeting the vibration amplitude in the low frequency range. The governing equations of motion of the hybrid passive damping system are derived through the Hamilton's principle. The obtained mathematical model is validated experimentally. The theoretical and experimental techniques presented provide an invaluable tool in controlling the multiple vibration modes across a wide frequency band.  相似文献   

18.
对航天器或者雷达天线进行隔振是减少其受到振动载荷的有效方法。采用一种基于3-SPR并联机构的稳定平台进行主动隔振。建立上平台坐标系、下平台坐标系、全局坐标系,分析推导3个坐标系的姿态变换矩阵,将3-SPR并联机构作为稳定平台进行运动学和静力学特性分析,建立包含下平台和上平台同时运动的运动学公式及其静力平衡方程和静力传递矩阵,提出主动隔振原理和隔振控制方法,并进行算例验证。为该并联机构稳定平台的优化设计和工程应用奠定理论基础。  相似文献   

19.
针对非线性低频隔振系统振动响应和振动传递率进行理论研究。基于非线性弹性元件的载荷-位移试验数据建立了非线性低频隔振系统的动力学模型和动力学方程。借助谐波平衡法对该非线性动力学方程进行近似求解,得到该非线性低频振动系统的一次谐波位移响应和振动传递率的近似表达式。分析了不同系统参数对振动传递率和曲线族骨架形状的影响,并对这种影响产生的原因进行了解释。理论结果与试验结果对比显示,当该非线性低频隔振系统工作在有效隔振频段内时,两者吻合良好。  相似文献   

20.

The nonlinear vibration response of a functionally graded materials (FGMs) truncated conical shell with piezoelectric layers is analyzed. The vibration amplitude is suppressed by the positive and inverse piezoelectric effects. And the bifurcation phenomenon is described to reveal the motion state of the conical shell. Firstly, a truncated conical shell composed of three layers is described. And the effective material properties of the FG layer are defined by the Voigt model and the power law distribution. Next, the electric potentials of piezoelectric layers are defined as cosine distribution along the thickness direction. Meanwhile, the constant gain negative velocity feedback algorithm is used to suppress the vibration amplitude by the electric potential produced by the sensor layer. Thereafter, considering the first-order shear deformation theory and the von Karman nonlinearity, the relationship between the strain and displacement is defined. And the corresponding energy of the conical shell is calculated. After that, the motion equations of the conical shell are derived based on the Hamilton principle. Again, the nonlinear single degree of freedom equation is derived by the Galerkin method and the static condensation method. In the end, the nonlinear vibration response of FGMs truncated conical shell with piezoelectric layers under the external excitation is analyzed via using the harmonic balance method and the Runge-Kutta method. The effects of various parameters, such as ceramic volume fraction exponent, external excitation’s amplitude, control gain and geometric parameters on the nonlinear vibration response of the system are evaluated by case studies. Results indicate that the control gain plays an important role on the suppression of the vibration amplitude. The ceramic volume fraction exponents are not sensitive to the nonlinear vibration response compared with other parameters. The bifurcation behavior is observed under different parameters. The FGMs truncated conical shell with piezoelectric layers has three types of motion state, such as periodic motion, multi-periodic motion, and chaos motion.

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