三偏心混沌混凝土振动台振动特性分析

Vibration Characteristics Analysis of Concrete Vibration Table Based on the Three Eccentric Chaotic Vibration Exciter

针对雷尔密特理论单一的激振频率只能对应一定粒径范围的骨料从而造成混凝土密实度不高的问题,建立了三偏心混沌激振器与双质体振动系统相结合的四自由度振动台力学模型,根据其在有势力和耗散力作用下的第二类Lagrange方程,推导出系统的动力学微分方程,通过Ode45(R-K)算法对振动过程进行仿真,利用得到的相轨图、Poincare图、功率谱图定性和最大Lyapunov指数定量表征振动台的振动特性,结果表明:振动台的振动为混沌振动,具有很宽的振动频率,能够对应混凝土骨料中不同粒径的共振频率。最后运用PFC 2D颗粒流分析软件对混凝土密实成型过程进行仿真验证,对比表明混沌振动台相比普通单一频率振动台混凝土密实度提高了6.32%,为工程实际中混凝土密实成型提供了理论依据。

As the vibration frequency only acts on a certain grain size range of concrete aggregate based on Schmidt theory, concrete density is not high by traditional means. Four degree of freedom mechanical vibrator model was established, which included three eccentric chaotic exciter and double-body. According to the power and dissipation force the second kind of Lagrange equation, the dynamic differential equations were derived. Through the simulation of vibration with Ode45（R-K）, the phase portrait, Poincare map, power spectrum and maximum Lyapunov index qualitative quantitative characterization of vibration motion state were studied. The results show that the vibration of mechanical vibrator is chaotic vibration. The wide band vibration corresponds to different resonance frequencies of different size concrete aggregate. By PFC 2D particle flow analysis software, concrete compacting forming process was simulated. The comparison shows that the compacting degree increased 6.32% with the chaotic vibration table. All these provide a theoretical basis concrete compacting.