Application of the sampling theory and methods in random decrement technique

This paper presents the application of sampling theory and methods on Random -Decrement (RD) method for parameter identification of linear dynamic system. The development of RD technique was elaborated briefly in the aspects of identifying the dynamic properties, and then this paper summarized the corresponding parameters recognition problems due to the quantity and quality of measured sampling segments. Detailed analysis of four kinds of sampling methods (the probability-proportional- to-size, stratified sampling, two-stage sampling and systematic sampling) is conducted to investigate their adaptation ranges in extracting RD signatures. The results of four simulated examples indicate that in view of the different vibration parameter recognition situations, the above provided RD technique based on different sampling methods could improve the quality of RD signatures obviously, and lead to a quite accurate identification of frequencies and damping ratios of structural system under the effective use of all measured sampling segments.