基于有效振动长度的多支撑斜拉索索力识别

Tension Identification of Stay Cable with Multiple Supports Based on Effective Vibration Length

为了解决斜拉桥拉索的计算长度难以界定、索力计算困难的问题,基于模态振型比与模态频率相结合的概念,提出了一种准确测定斜拉索索力的新方法。该方法通过引入有效振动长度的概念,将复杂边界条件的斜拉索等效为简支欧拉梁,从而可以采用既有的索力计算公式进行计算。通过振动测试得到多阶振型和频率,将理论振型与实测振型之间的误差的平方和作为目标函数,采用优化的方法可以准确求解得到拉索的有限振动长度。最后通过数值算例,验证了方法的正确性。

In order to solve the problem that the calculation length of cables of cable-stayed bridges is hard to define and the calculation of cable forces is difficult, based on the concept that combines the ratio of modal to vibration mode and modal frequencies, a new method was proposed to accurately determine the cable tension. By introducing the concept of effective vibration length, the cable under complex boundary conditions was equivalent to simply supported Euler beam, so that the existing cable force calculation formula could be applied to the calculation. Multiple vibration modes and frequencies were obtained through vibration tests. The sum of the squared errors between the theoretical and measured vibration modes was set as an objective function. The accurate solution to the finite vibration length of the cable was achieved by the optimized method, and numerical examples were used to verify the correctness of the method.