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Fiber Bragg grating sensor-based local crack real-time monitoring method

A technology of optical fiber Bragg and real-time monitoring, which is applied in the direction of optical testing flaws/defects, etc., and can solve the problems of complex equipment, lightness and insensitivity of monitoring

Inactive Publication Date: 2016-09-21
BEIHANG UNIV
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  • Claims
  • Application Information

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Problems solved by technology

But they all have the following two problems: one is that the equipment is complex and not light enough; the other is that it is not sensitive to small damage monitoring such as local cracks

Method used

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  • Fiber Bragg grating sensor-based local crack real-time monitoring method
  • Fiber Bragg grating sensor-based local crack real-time monitoring method
  • Fiber Bragg grating sensor-based local crack real-time monitoring method

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Embodiment Construction

[0039] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0040] The present invention provides a real-time monitoring method for local cracks based on fiber Bragg grating sensors. The overall process diagram of the method is as follows figure 1 Shown. The method is specifically implemented through the following steps:

[0041] The first step is to perform a finite element analysis on the aluminum alloy plate with a central circular hole subjected to uniaxial fatigue load;

[0042] The most common structure and load situation in simulation engineering is that an infinite flat plate with a central circular hole is subjected to uniaxial fatigue load. This embodiment uses an aluminum alloy plate test piece with a size of 600mm×300mm×2mm, a hole with a diameter of 10mm is opened in the middle, and a 3mm notch is prefabricated on the edge of the hole by wire cutting. The maximum test stress is 75MPa, the stress ratio is 0.1...

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Abstract

The invention discloses a fiber Bragg grating sensor-based local crack real-time monitoring method, and belongs to the technical field of structure healthiness monitoring. Strain distribution of the tip of a crack has an obvious non-uniform characteristic, so when a fiber Bragg grating sensor undergoes non-uniform strain in the grid length direction, the shape and the position of a reflection spectrum change. When the strain gradient is different, the spectrum change degree is different. A structure position to be monitored is simplified, finite element analysis is carried out to obtain the strain distribution under different crack lengths in order to determine the layout of the sensor, the characteristic parameter of the reflection spectrum change is extracted, and a quantitative relationship between the characteristic parameter and the crack length is established in order to realize real-time monitoring of the crack in a limit length range. A plurality of sensors are arranged along the crack expansion direction, and a distance between adjacent sensors is smaller than or equal to the effective detection range of the next sensor, so the real-time monitoring of the crack with any prescribed length can be realized.

Description

Technical field [0001] The invention belongs to the technical field of structural health monitoring, and specifically relates to a real-time monitoring method for local cracks based on a fiber Bragg grating (FBG) sensor. Background technique [0002] Cracks are one of the typical damage types in the structure. Important structures will inevitably produce cracks during the expected or additional period of use. If the initiation and expansion of these cracks cannot be monitored in a timely and accurate manner, major accidents may occur. Therefore, crack monitoring is essential to improve structural safety. important. Among them, pore structures and notches are the most common places for cracks, so real-time monitoring of such local cracks is very important. In recent years, in order to realize the identification and monitoring of local crack damage, structural health monitoring technology has been developed rapidly. Structural health monitoring technology is a cutting-edge techn...

Claims

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Application Information

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IPC IPC(8): G01N21/88
CPCG01N21/88
Inventor 刘晓鹏张卫方何晶靖王邓江
Owner BEIHANG UNIV
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