粘弹性支座RC梁在低速冲击下的弹性响应分析

ELASTIC RESPONSES OF RC BEAMS WITH VISCOUS-SPRING SUPPORTS SUBJECTED TO LOW VELOCITY IMPACT

  • 摘要: 基于Euler-Bernoulli梁理论,分析了具有粘弹性支座的钢筋混凝土梁在低速冲击作用下的弹性动力响应问题。根据准静态Hertz接触理论和梁的横向振动方程,建立了梁在弹性阶段的动力响应方程组,给出了梁动力函数和支座动力函数的计算方法。研究表明:粘弹性支座使梁的位移峰值减小,而且位移到达峰值的时间也有所延后,有利于提高梁结构的抗冲击能力。与刚性支承相比,粘弹性支座的附加惯性力降低了梁动力函数和支座动力函数值,并降低了梁的振动频率;梁动力函数和支座动力函数值随支座阻尼增大而减小,且支座阻尼加速了动力函数值衰减;除了采用粘弹性支座外,缩短冲击荷载的作用时间也可以减小结构的动力响应。

     

    Abstract: The responses of reinforced concrete beams with viscous-spring supports subjected to low velocity impact are analyzed based on the theory of Euler-Bernoulli beams. The equations of dynamic responses for elastic phases are established according to the quasi-static Hertz contact theory and vibration equations of beams under dynamic loads, then the calculation methods of dynamic functions for both beams and supports are given. Calculation examples show that the peak displacements of beams with viscous-spring supports are reduced obviously, the times corresponding to peak displacements are delayed, and the impact resistances of the beams are enhanced. The values of dynamic functions for both beams and supports are reduced due to the additional forces on the supports, and the vibration frequencies of beams tend decrease because of the viscous-spring supports. The values of dynamic functions for both beams and supports decrease with the increasing of support dampings, and the attenuation values of dynamic functions are augmented by the support dampings. Except for the viscous-spring supports, the dynamic responses of beams can be reduced by shortening the duration of dynamic loads.

     

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