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961.
962.
针对振动系统在随机激励下的响应进行结构动力修改是具有实用价值的工程问题。本文以系统在道路随机激励下的加速度响应为目标,借助于系统模态及响应的灵敏度分析和矩阵摄动法,对大型机动电子方舱系统进行了快速结构动力修改。 相似文献
963.
964.
Analysis of strongly nonlinear (vibro-impact) systems revealed an existence of nonlinear modes of vibration with spatial and
temporal concentration of energy. The modes can be realised, for example, through intensification of the vibration process
by condensing the vibration into a sequence of collisions for impulsive action of the tools to the media being treated or
can be as a result of some discontinuity (slackening of a contact, arrival of crack, etc.) in the structure. The use of the
nonlinear modes to develop useful mechanical work leads to necessity of excitation and control of resonance in ill-defined dynamical systems. This is due to the poorly predictable response of the media being treated. Excitation, stabilisation and
control of a nonlinear mode at the top intensity in such systems is an engineering challenge and needs a new method of adaptive
control for its realisation.
Such a control technique was developed with the use of self-exciting mechatronic systems. The excitation of the nonlinear
mode in such systems is a result of artificial instability of mechanical system conducted by positive electronic feedback.
The instability is controlled by intelligent identification of the mode and active tracing of the optimal relationship between
phase shifting and limitation in the feedback circuitry. This method of control is known as autoresonance. Applications of autoresonant control for development of the new machines are described.
The paper is a revised and extended version of authors’ presentation at ASME 2004 International Mechanical Engineering Congress,
Anaheim, CA, USA.
An erratum to this article can be found at 相似文献
965.
The study sets up a simple model for predicting vibration induced sliding of mass, and provides quantitative experimental evidence for the validity of the model. The results lend confidence to recent theoretical developments on using vibration induced sliding for passive vibration damping, and contributes to a further understanding of this nonlinear phenomenon. A mathematical model is set up to describe vibration induced sliding for a base-excited cantilever beam with a spring-loaded pointmass. Approximations simplify the model into two nonlinear ordinary differential equations, describing motions of the system at near-resonant excitation of a single beam mode. This simplified model is studied numerically and analytically, and tested against laboratory experiments. The experiments provide evidence that the simplified mathematical model retains those features of the real system that are necessary for making useful predictions of transient and stationary first-mode response. 相似文献
966.
线性变厚度矩形薄板自由振动的精确解 总被引:3,自引:0,他引:3
基于小挠度薄板理论,采用Lery法结合Frobenius法构造的幂级数解,得到了两对边简支另两对边为SS、CS、FF支承的三种线性变厚度矩形薄板的自振频率随板的边长比及厚度比变化的精确解及其振型函数的解析表达式。 相似文献
967.
机械振动信号盲源分离的时域方法 总被引:1,自引:0,他引:1
介绍盲源信号分离基本原理,分析了瞬态混叠模型和卷积混叠模型的特征,给出两个源信号独立性的评判准则,研究了盲分离正确性的评价误差函数,进行数值仿真,并用时域卷积瞬态混叠模型对实际机械振动信号进行源信号的盲分离。数值仿真和实际信号的分离效果较好,说明所用方法在机械振动信号盲源分离中的适用性。文中还分析了多源信号分离中所用方法的收敛性。 相似文献
968.
Summary In this paper, a new asymptotic calculation method is presented for a class of nonlinear nonautonomous vibration systems with multiple external periodic interferences. Simple calculation formulae of an asymptotic solution for resonance and off-resonance vibration are derived. The paper is concerned with a vibration system representing a class of nonlinear oscillators. Consequently, the calculation of a class of nonlinear oscillators is routinized. Two different Duffing equations are verified which shows that the results are completely in accordance with the solutions of references [3, 4, 6]. The derivation of solutions of Duffing equations becomes easier and simpler. In addition, some errors in reference [6] are pointed out. 相似文献
969.
本文用摄动法导出了弦的非线性振动的K-dV方程,讨论了只有耗散和色散的特殊情况,然后详细讨论了K-dV方程的孤波解的性态,并给出了弦的非线性振动孤波的主要特征。 相似文献
970.
This study focuses on an algorithm for the simultaneous identification of Coulomb and viscous damping effects from free-vibration decrements in a damped linear single degree-of-freedom (DOF) mass-spring system. Analysis shows that both damping effects can indeed be separated. Numerical study of a combined-damping system demonstrates a perfect match between the simulation parameters and the estimated values. Experimental study includes two types of real systems. The method is applied to an experimental industrial bearing. Experimental results are compared with numerical simulations to illustrate the reliability of this method. An analysis provides conservative bounds on error estimates. An example of the effect of quantization error on the estimations is included. 相似文献