变速移动载荷作用下黏弹性地基梁动力响应1)

DYNAMIC RESPONSE OF A BEAM ON VISCOELASTIC FOUNDATION UNDER LOAD OF VARIABLE MOVING SPEED^1)

  • 摘要: 利用振型叠加法和Duhamel积分推导得到了在变速移动载荷作用下黏弹性地基梁的动力响应解析解。然后采用Gauss-Legendre求积公式对积分表达式进行计算,研究了移动载荷的初速度、加速度和地基参数对梁挠度的影响。结果表明:梁的挠度随着载荷初速度和加速度的增大而明显减小;此外计算发现增大地基剪切力、地基阻尼和弹性模量可以有效减小梁的挠度,并且梁动力响应的滞后现象还与地基阻尼有关,阻尼越大滞后现象越明显。

     

    Abstract: The integral expression of dynamic deflection of the beam on viscoelastic foundation to a load moving with variable speed is derived using modal superposition and Duhamel's integral. By employing Gauss-Legendre integration rule, a practical example is chosen to obtain the numerical results. The influences of initial moving velocity, acceleration and parameters of subgrade on the dynamic deflection are discussed. The results indicate that the initial velocity of the moving load have influence on the dynamic response. The dynamic deflection of beam decreases significantly with the increase of the initial moving velocity and acceleration. In addition, it is found that the dynamic deflection of beam decreases with the increase of the shear coefficient, damping and elastic foundation modulus of the foundation and the hysteresis of the dynamic response of the beam is related to the damping, as the damping goes higher, the hysteresis becomes more obvious.

     

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