System and method for intelligent monitoring strain and temperature of bullet tank based on distributed optical fibers

An intelligent method for monitoring strain and temperature of a bullet tank based on distributed optical fibers, comprising the following steps:

• step 1:
• establishing a 1:1 simulation model of a bullet tank body (1) and a sand bed foundation (11) below in a finite element software through a numerical simulation system (10), and conducting simulations under different working conditions to determine a temperature, stress and strain change range as an initial range for monitoring by a field control system (8);
• step 2:
• laying distributed strain fiber optic cables (2) and distributed temperature fiber optic cables (3) in a * shape from a head of the bullet tank body (1), laying a plurality of soil pressure gauges (4) in the sand bed foundation (11) under a landing position of the bullet tank body (1), and landing the bullet tank body (1) with the fiber optic cables laid onto the sand bed foundation (11);
• step 3:
• gathering temperature data collected by the distributed temperature fiber optic cables (3) to a temperature collector (5), gathering strain data collected by the distributed strain fiber optic cables (2) to a strain collector (6), gathering soil pressure basic values collected by the soil pressure gauges (4) to a soil pressure collector (7), correcting and calibrating an accuracy of each collector, transmitting the data of each collector to the field control system (8) for comparison and analysis to determine whether the data is within the initial range, proceeding to step 4 if the data is within the initial range, otherwise, adjusting the initial range of the field control system (8) and correcting a simulation module of the numerical simulation system (10);
• step 4:
• conducting a hydrostatic test on the bullet tank body (1), further refining and correcting the strain monitoring range by the field control system (8) based on the data collected by the strain collector (6) and the soil pressure collector (7), and acquiring a temperature difference between an inside and an outside of the bullet tank body (1) through comparison to serve as a corrected value for other subsequent tests;
• step 5:
• conducting a filling test on the bullet tank body (1), monitoring surface temperature data of the bullet tank body (1) through the distributed temperature fiber optic cables (3), establishing a relationship with a filling rate, monitoring surface strain of the bullet tank body (1) through the distributed strain fiber optic cables (2), and establishing a relationship with a filling volume so as to establish a temperature compensation relationship for the strain;
• step 6:
• conducting a leakage simulation test on the bullet tank body (1), observing changes of the temperature collector (5) and the strain collector (6), adjusting the accuracy of the collectors based on the changes, and adjusting the control accuracy of the field control system (8);
• and
• step 7:
• starting an intelligent identification mode of the field control system (8) for intelligent monitoring:
• firstly, controlling each collector to conduct trial collection, comparing the collected data with the data range stored in the field control system (8), selecting the most approximate data as a data collection condition, issuing an instruction of adjusting the accuracy as the collection accuracy under the current condition to each collector, conducting corresponding adjustment by the numerical simulation system (10) based on the condition selected by the field control system (8),
• forming temperature and strain cloud images by the adjusted numerical simulation system (10) based on the data transmitted by the field control system (8), transmitting the monitoring data and cloud image data by the field control system (8) to a central control display screen (9) for display, comparing, by the field control system (8), the collected data with the initial range stored in the field control system in real time, transmitting warning information to the central control display screen (9) in the case that the detected data is out of the range, and
• for the leakage situation, positioning a leakage position according to the following formula:
• T
• =
• (
• ∫
• ∫
• 0
• L
• 2
• α1
• ⁢
• dT
• dr
• 2
• +
• ∫
• 0
• L
• 2
• α1
• ⁢
• 2
• r
• ⁢
• dT
• dr
• )
• +
• (
• ∫
• ∫
• 0
• R
• α2
• ⁢
• dT
• dr
• 2
• +
• ∫
• 0
• R
• α2
• ⁢
• 2
• r
• ⁢
• dT
• dr
• )
• +
• T
• C
• 3
• wherein T denotes a temperature;
• TC denotes an ambient temperature at the distributed temperature fiber optic cables (3);
• R denotes a radius of the bullet tank body (1);
• α1 denotes thermal diffusivity of soil;
• α2 denotes thermal diffusivity of the tank body;
• L denotes a radial distance between the adjacent distributed temperature fiber optic cables (3);
• and r denotes a shortest distance from a leakage point to a measurement point of the distributed temperature fiber optic cables (3) or a distance from the measurement point of the distributed temperature fiber optic cables (3) to the inside of the tank body.