| FFT is widely used in engineering signal processing which has the advantages of small calculation, fast speed and high efficiency. Under the nonlinear force of fluid and solid, the combined pipeline structure of Ocean Engineering presents a very complicated vibration mode and the amplitude significantly increased. This phenomenon has brought huge potential risk to the safety and reliability of engineering structure. On account of complicated vibration mode analysis of depth combined cylindrical by FFT technology, a profound understanding of flow induced vibration mechanism and further suppression of vibration damage have important theoretical significance and practical value in engineering. Generally speaking, FFT plays a important role in promoting the development of digital signal processing, engineering vibration analysis and other relevant disciplines. In addition, FFT has always been improving to satisfy the need of different engineering applications. It also acquires great progress and all-round development meanwhile.In this paper, author firstly analyzed some theoretical knowledge and relevant algorithms based on FFT.Secondly, the characteristics of engineering vibration signal are analyzed centering on the basic theory and concept of FFT. The main focus of the paper are the method research of vibration signal analysis in rotating machinery bearing; the vibration signal analysis aiming at the quality evaluation of the main reducer; the analysis of noise from main reducer and vibration signal status and the application of FFT+FT spectrum in the dynamic assembly test. Then, the stress relationship of the riser vortex induced vibration is further discussed.At last, author analyzed and verified the reliability of the numerical model by means of single cylindrical VIV and tandem double cylindrical VIV and put the focus on the locking scope and amplitude variation of VIV under the two constraints and the two cylindrical vibration correlation. |
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