声学黑洞梁的振动碰撞动力学建模与分析

Modeling and Analysis of Vibro-impact Dynamics of Acoustic Black Hole Beam

  • 摘要: 为研究声学黑洞(acoustic black hole,ABH)梁的振动碰撞响应,本文提出了一种半解析动力学建模与响应特性的分析方法。首先,基于Euler-Bernoulli梁理论和Rayleigh-Ritz方法建立系统的运动方程,并根据赫兹接触理论推导非线性碰撞力和接触刚度。之后,采用第一类切比雪夫多项式构造模态函数,通过求解特征值问题得到系统的固有频率和模态振型函数。在此基础上,运用Duhamel积分和时间步进迭代法计算振动碰撞响应。本文研究了多项式的项数、边界弹簧刚度等关键参数对于固有频率的影响。与试验结果的对比表明,所提方法能够准确求解ABH梁在连续碰撞下的振动响应。通过数值计算,分析了碰撞位置和间隙、基础激励频率和振幅对振动碰撞响应的影响。结果表明,在所研究的参数范围内,碰撞点挠度和碰撞力幅值随着碰撞位置和基础激励振幅的增加而增加,随着碰撞间隙和基础激励频率的增加,两者均呈现先增加后减小的变化趋势。通过和均匀梁比较验证了碰撞下ABH梁在压电能量采集和阻尼减振方面具有优势。

     

    Abstract: In order to study the vibro-impact response of an acoustic black hole (ABH) beam, a semi-analytical dynamic modeling and analysis method of response characteristics is proposed. Firstly, the motion equation of the system is established based on Euler-Bernoulli beam theory and Rayleigh-Ritz method, and the nonlinear impact force and contact stiffness are derived according to Hertz contact theory. Afterwards, the first-kind Chebyshev polynomials are used to construct the modal function, and the natural frequency and mode shape function of the system are obtained by solving the eigenvalue problem. On this basis, the Duhamel integral and time-stepping iteration method are used to calculate the vibro-impact response. The influences of key parameters such as the number of terms in the polynomial and the boundary spring stiffness on the natural frequency are studied. Comparison with experimental results shows that the proposed method can accurately solve the vibration response of ABH beams under continuous collision. Through numerical calculation, the influence of impact position and gap, base motion excitation frequency and amplitude on the vibro-impact response is analyzed. The results show that within the parameter range studied, the deflection of impact position and the impact force magnitude increase with the increment of the impact position and the base motion excitation amplitude, and increase first and then decrease with the increment of the impact gap and the base motion excitation frequency. By comparing with the uniform beam, it is verified that the ABH beam has advantages in piezoelectric energy harvesting and damping vibration reduction under impact.

     

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