基于动力刚度法的体外预应力梁自振频率分析

用预应力梁-杆组合结构模拟体外预应力梁,以体外预应力简支梁为例,建立了预应力梁杆单元动力刚度矩阵。采用动力刚度法,进一步推导出预应力梁-杆组合结构的整体动力刚度矩阵,利用Williams-Wittrick算法求解频率。本文以理论推导为基础,引入了动力刚度法。最后通过算例,讨论了各种因素对梁横向的振动特性的影响,并与试验值比较。计算结果表明:动力刚度法能够精确有效的求解体外预应力混凝土梁的横向振动问题。

Dynamic stiffness matrix method for vibration analysis of an external prestressed beam

The prestressed beam-bar composite structure model is introduced to simulate the external prestressed beam. A simply-supported external prestressed beam is studied. Dynamic Stiffness Matrix Method is used to establish the element and global dynamic stiffness matrices for the beam-bar composite structure of the external prestressed beam. As a result, the solution of the frequency is obtained by Williams-Wittrick algorithm. Based on theoretical derivation, dynamic stiffness method is introduced. The influence on the natural frequencies of the beam is also discussed. Numerical results show that dynamic stiffness matrix method is reliable and efficient, and is well applicable to engineering problems.