A Preliminary Positioning Method for Added Mass of Beam Structures Based on Frequency
A technology of additional mass and preliminary positioning, applied in the direction of measuring devices, instruments, etc., can solve the problems that are difficult to meet, and the research on the preliminary positioning of the additional mass of beam structure has not been reported, and achieve the effect of simple operation
Active Publication Date: 2021-06-22
HOHAI UNIV
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Problems solved by technology
However, these non-destructive testing techniques are local testing methods, and generally need to predict the approximate position of the additional mass, which is difficult to meet in practical applications.
As the overall modal parameter of the structure, the frequency is combined with the frequency characteristic curve of the beam structure caused by the additional mass to form an additional mass position index. The research on the preliminary positioning of the additional mass of the beam structure has not been reported yet.
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[0051] Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:
[0052] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
[0053] Such as figure 1 As shown, a frequency-based preliminary positioning method for beam structure additional mass proposed by the present invention includes the following steps:
[0054] Step 1. Measure the natural frequency f before and after the M (M ≥ 5) order added mass in front of the beam structure j , Compute the relative rate of change of frequency and normalize it:
[0055]
[0056]
[0057] Among them, j∈{1,2,...,M} is the frequency order, Δf j Represents the relative rate of change of the jth order frequency, Represents the frequency relative rate of change of...
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The invention discloses a frequency-based preliminary positioning method for additional mass of a beam structure. The steps include: measuring the beam structure before M ( M ≥5) natural frequencies before and after the additional mass, calculate the relative frequency change rate, and normalize it; calculate the frequency characteristic curve of the beam structure caused by the additional mass; according to the normalized frequency relative change rate and frequency characteristic curve, before calculation M The first-order single-order additional quality position index is fused to obtain the overall additional quality position index; the additional quality is initially located according to the position where the overall additional quality position index peak appears. The invention can be used to analyze the natural frequency before and after the added mass of the beam structure, and then realize the preliminary positioning of the added mass.
Description
technical field [0001] The invention discloses a frequency-based preliminary positioning method for additional mass of a beam structure, and specifically relates to the technical field of state monitoring of beam structures. Background technique [0002] Beam structures, such as fan blades, are prone to produce additional masses such as snow and ice when they serve in cold environments. If these additional masses cannot be detected and dealt with in time, they will affect the safe and reliable operation of the overall structure. In this context, some non-destructive testing techniques have developed rapidly in recent years and have been used to detect the additional quality of structures. Non-destructive testing techniques such as ultrasonic testing have been applied to additional quality testing of beam structures. However, these non-destructive testing techniques are local testing methods, and generally need to predict the approximate position of the additional mass, whic...
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IPC IPC(8): G01B21/00
CPCG01B21/00
Inventor 曹茂森沙刚刚李大洋
Owner HOHAI UNIV