Weak modal identification and time domain reconstruction method for ocean structure

Abstract

The invention relates to a weak modal identification and time domain reconstruction method for an ocean structure, and particularly provides a method for the weak modal identification of the ocean structure when the test signal of the ocean structure contains a high-level noise. The method comprises the steps of S1, acquiring the really measured signal of the ocean structure; S2, conducting the anharmonic decomposition on the really measured signal; S3, separating and identifying the extreme values of a weak modal; S4, constructing the time domain signal of the weak modal. According to the technical scheme of the invention, the defect in the prior art that based on the conventional modal recognition method, the weak modal submerged in a high-level noise is difficult to extract can be overcome. Based on the fact that both extreme values and residue values are complex numbers, the time sequence form of really measured signals is constructed. Therefore, time-domain signals can be reconstructed more accurately. Meanwhile, the method provides a novel means for the weak modal extraction of the ocean structure and the time domain reconstruction, thus being wide in the prospect of engineering application.

Description

technical field [0001] The invention relates to an ocean structure weak mode identification and time domain reconstruction method, in particular to the problem of ocean structure weak mode identification when the ocean structure test signal contains high level noise. Background technique [0002] In recent years, countries have paid more and more attention to the development and utilization of marine resources, and have successively built many marine engineering structures such as cross-sea bridges, offshore platforms, submarine oil and gas pipelines, submarine tunnels, and super-large floating bodies. This type of structure is prone to harmful vibrations under the action of external loads such as waves, currents, and earthquakes. In severe cases, fatigue damage may occur, and its construction is difficult and maintenance costs are high. Therefore, in order to ensure the safe service of marine structures and avoid major It is of great significance to detect the structural da...

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Problems solved by technology

[0006] The purpose of the present invention is to propose a method for weak mode identification and time domain reconstruction of marine structures aimed at the defects existing in the prior art, and to overcome the difficult problem that traditional mode identification methods are difficult to extract weak modes submerged in high-level noise. At the same time, the damping characteristics are considered when the signal is subjected to anharmonic decomposition, so that the time domain signal reconstruction is more accurate

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