A method for detecting delamination damage position of composite laminated beam
A composite material layer, damage location technology, applied in material inspection products, analytical materials, measuring devices, etc., can solve problems such as difficulty in meeting, and achieve the effect of simple operation
Active Publication Date: 2021-04-06
HOHAI UNIV
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Problems solved by technology
However, these methods generally need to predict the approximate location of the delamination damage, and the location of the delamination damage must be easily accessible, which is difficult to meet in practical applications.
However, based on the dynamic parameters of composite laminated beams: natural frequency and mode shape, the delamination damage index is formed, and the research on detecting delamination damage of composite laminated beams has not been reported yet.
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[0042] Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:
[0043] 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.
[0044] like figure 1 As shown, a method for detecting the delamination damage position of a composite material laminated beam proposed by the present invention comprises the following steps:
[0045] 1. Measure the natural frequency ω of the first m (m ≥ 5) layers of composite laminated beams before and after damage j , Calculate the relative rate of change of the natural frequency and standardize it as [01] interval:
[0046]
[0047]
[0048] Among them, j∈{1,2,...,m} is the frequency order, Δω j Represents the relative rate of change of the jth order natural frequency, δω ...
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The invention discloses a method for detecting the delamination damage position of a composite material laminated beam. The steps include: measuring the natural frequencies before and after damage of the first 10 orders of the composite material laminated beam and the mode shape after damage; calculating the relative change rate of the natural frequency, and standardize it; calculate the square of the first-order derivative of the mode shape and standardize it; calculate the first 10 single-order layer damage indicators according to the normalized relative change rate of natural frequency and the square of the first-order derivative of the mode shape, and divide the first 10 The overall delamination damage index is obtained by multiplying the single-order delamination damage index; the delamination damage position is determined according to the position where the maximum value of the overall delamination damage index appears. The invention can be used to analyze the natural frequency before and after delamination damage of composite material laminated beams and the mode shape after damage, and then judge the delamination damage position.
Description
technical field [0001] The invention discloses a method for detecting the delamination damage position of a composite material laminated beam, and specifically relates to the technical field of composite material laminated beam structural damage detection. Background technique [0002] Composite laminated beam structures are vulnerable to impact and cause fine delamination damage during long-term service. These subtle layered damages will accumulate and evolve into macroscopic damages that endanger the safe and reliable operation of the overall structure. Based on this, various nondestructive testing methods have developed rapidly in recent years, and local nondestructive testing methods such as ultrasonic, electromagnetic field, and eddy current have been widely used in the delamination damage detection of composite laminated beams. However, these methods generally need to predict the approximate location of the delamination damage, and the location of the delamination dam...
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IPC IPC(8): G01N33/00
CPCG01N33/00G01N33/0078G01N33/0003
Inventor 曹茂森沙刚刚
Owner HOHAI UNIV