论文部分内容阅读
考虑大变形的影响,建立了高桥墩在横向冲击荷载作用下的非线性动力学基本方程式;通过位移形函数假设,采用伽辽金积分方法得到了时间变率的动力学控制方程;对时间变率的非线性微分方程进行数值求解,给出了不同冲击荷载作用下不同柔度高桥墩的位移响应曲线以及其从产生横向振动到失稳的全过程,得到了横向冲击时高桥墩失稳的临界冲击荷载和失稳时刻;通过数值算例比较了三角形和矩形冲击荷载作用下高桥墩的荷载-位移响应曲线;分析了横向冲击力幅值、冲击区域大小、冲击持续时间、高桥墩柔度、桥面质量大小对位移幅值响应曲线、临界冲击荷载、失稳时刻的影响。结果表明:无论是在矩形还是三角形形式横向冲击作用下,随着冲击区域的增大高桥墩的振动幅值变大;桥面简化质量越大,高桥墩失稳的临界冲击载荷越小;柔度越大时,高桥墩失稳的临界冲击荷载幅值越小;对于矩形冲击,当冲击持续时间大于1s后,冲击持续时间的增加对高桥墩的稳定性无明显影响;对于三角形冲击荷载,随着冲击持续时间的增大高桥墩的振动幅值变大。
Considering the influence of large deformation, the nonlinear dynamic basic equation of high piers under lateral impact loads is established. By using the displacement shape function assumption, the governing equations of dynamics of time variability are obtained by the Galerkin integral method. The nonlinear differential equations are solved numerically. The displacement response curves of high pier with different flexibility under different impact loads and the whole process from lateral vibration to instability are obtained. The instability of high pier under transverse impact is obtained The critical impact load and the moment of instability are analyzed. The load-displacement response curves of high piers under triangular and rectangular impact loads are compared by numerical examples. The influences of transverse impact force amplitude, impact area size, impact duration, high bridge pier flexibility , The effect of deck mass on displacement amplitude response curve, critical impact load and moment of instability. The results show that the vibration amplitude of high pier increases with the increase of impact area under the transverse impact of rectangular or triangular form. The greater the simplified mass of bridge deck, the smaller the critical impact load of high pier failure. The higher the degree is, the smaller the amplitude of the critical impact load of the high bridge piers instability is. For the rectangular impact, when the impact duration is more than 1s, the increase of the impact duration has no significant effect on the stability of the high piers. For the triangular impact loads, As the impact duration increases, the vibration amplitude of high pier increases.