Low speed impact position identification method based on approximate entropy calculation

Abstract

The invention discloses a low speed impact position identification method based on approximate entropy calculation and belongs to the impact monitoring technology field of structure health monitoring. The method comprises the following steps of step1, carrying out distributed optical fiber bragg grating sensor layout; step2, adopting a calculating method of optical fiber bragg grating sensor impulse response signal approximate entropy; step3, collecting an optical fiber bragg grating sensor response signal corresponding to an impulse point to be measured and carrying out approximate entropy calculation; step4, determining an area where the point to be measured is located and calculating an approximation entropy of a sample impulse point response signal in the area; step5, constructing a relation model of a distance of the impulse point to a sensor and a corresponding approximation entropy difference value; and step6, based on a three-line crossing method, determining a position of the impulse point to be measured. A positioning algorithm in the invention possesses characteristics that a lot of prior knowledge is not needed; and practicality is high and so on.

Description

technical field [0001] The invention belongs to the technical field of impact monitoring for structural health monitoring, in particular to a plate structure impact monitoring method capable of quantitatively estimating the approximate entropy of signal complexity. Background technique [0002] It is difficult to monitor the low-speed impacts of bridge buildings, aerospace vehicles and other structures from falling parts, high-speed moving debris, flying birds in the air and ground vehicles. These low-speed impacts may cause damage that is difficult to observe from the outside with the naked eye. These damages are not noticeable, but slowly expand over time and can eventually be catastrophic. Therefore, timely low-speed impact monitoring is very necessary to provide early warning for potential dangers and remind relevant personnel to do maintenance work to ensure the safety and reliability of the structure. [0003] At present, in the shock load location identification meth...

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Problems solved by technology

[0003] At present, in the shock load location identification method based on the study of shock excitation of Lamb waves in the plate structure, triangular location, quadrilateral location, and time difference location based on wavelet transform are usually used, and good shock location identification results have been achieved. There are complex phenomena such as dispersion in the wave propagation process, which directly reduces the accuracy of positioning based on Lamb waves

In addition, impact location identification methods based on neural networks, support vector machines, etc. that require a large amount of prior knowledge require heavy work before positioning to obtain sample signals of each impact point, and then let the signal of the point to be measured be substituted into the trained classifier For pattern recognition, such methods are less practical

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