水平弹性支撑圆拱的动力特性研究

用柔度法建立了水平弹性支撑拱结构的自由振动方程,考虑了拱脚处集中质量的附加惯性力. 计算分析了水平弹性支撑对两铰圆拱固有特性的影响,水平弹性支撑会使拱结构的自振频率减小,当拱结构的矢跨比为0.1 左右时影响最为显著,同时还会改变拱结构的振动形态,尤其在高阶振型中将完全按照梁的特点振动.分析了圆弧梁与两铰圆拱的振动内力特点,提出了柔度系数的概念,经过计算得到了水平弹性支撑拱转化为两铰圆拱和圆弧梁的临界柔度系数以及对应的临界刚度系数.

DYNAMIC CHARACTERISTICS OF THE HORIZONTAL ELASTIC SUPPORT CIRCULAR ARCH

The free vibration equation for the horizontal elastic support arch structures is established by the flexibility method. The additional inertia force of the arch foot mass is taken into account. The influence of the horizontal elastic support on the inherent characteristics of the two-hinged arch is analyzed. The natural frequency is shown to be decreased. The influence is the largest at the rise span ratio of 0.1. The horizontal elastic support affects the vibration modes. Especially for higher modes, the horizontal elastic support arch vibrates completely in accordance with the circular beam. The vibration internal force characteristics of the circular beam and the two-hinged circular arch are analyzed. The concept of the flexibility coefficient is put forward. The critical flexibility and the corresponding critical stiffness are obtained.