The Improvement of Random Decrement

The free response signal is the foundation of vibration signal analysis and recognition. But under the restrictions of engineering conditions, the number of sampling points is usually not large enough to meet the requirement of Random Decrement Technique (RDT). Thereby, the free response signal obtained contains relatively strong noise. Aiming at the shortcoming of the classical RDT, a multi-secant method of the improved RDT is proposed in this paper. A satisfactory free response signal can be obtained at the condition of small number of sampling vibration signal through the new method, so that the result can be applied to algorithms of time domain identification. Through the testing of the vibration response signal of the stayed cable of the bridge, the recognition accuracy of the free response function is improved under the condition of the calculating speed not changing. Thus, this method is possessing applicable value in engineering.