3results about How to "With anti-electromagnetic interference" patented technology

The invention discloses a distributed optical fiber-grating-based rockburst test system and method, solves the problem that in the prior art, only strain parameters are simply obtained in a rockburst test, and has the beneficial effects of accurately simulating rockburst and obtaining related parameters of the rockburst. According to the specific scheme, the rockburst test system based on the distributed optical fiber-grating comprises a test device, the test device comprises a vibration table, and the vibration table supports a supporting box body; the rock sample is provided with an optical fiber channel, and the distributed optical fiber penetrates into the optical fiber channel; the vibration table, the stress applying component and the drilling disturbance component are respectively connected with the control unit; the monitoring unit is connected with the distributed optical fiber and the grating optical fiber; the monitoring unit sends monitored data to the control unit, and the control unit judges when rockburst is triggered and obtains stress change, elastic strain energy release amount and strain abrupt change time difference at the moment of rockburst when the rockburst occurs.

This invention discloses a fiber Bragg grating level sensor based on liquid pressure conversion, comprising a fiber Bragg grating demodulator, a 2×1 fiber coupler, a transmission fiber, and a sensing unit. The sensing unit consists of a strain-sensing fiber Bragg grating, a temperature-compensated fiber Bragg grating, a sealed cylinder, a support beam, a pressure block, a pressure tension frame, a sealing membrane, and a stop. The pressure block and the pressure tension frame convert liquid level changes into longitudinal displacement changes, causing axial strain in the strain-sensing fiber Bragg grating. This results in a drift in the center wavelength of the strain-sensing fiber Bragg grating, and the liquid level height of the container is measured by monitoring this wavelength change. This invention eliminates the influence of temperature on the liquid level measurement results through a temperature-compensated fiber Bragg grating, offering advantages such as a large measurement range, good practicality, simple structure, low cost, good stability, high sensitivity, and safety and reliability, meeting the needs of measuring liquid levels in large storage tanks and other applications.

The invention belongs to the technical field of ship lock structure damage identification, and particularly provides a miter gate crack identification early warning method and system based on a fiber grating displacement sensing technology, and the method comprises the steps: collecting displacement data collected by fiber grating displacement sensors at all measurement points of a miter gate, and carrying out the smoothing of the displacement data through a filter; performing first-order difference calculation and curvature calculation on the smoothed displacement data to obtain a difference curve and a curvature curve; extracting peak points from the difference curve and the curvature curve by adopting a peak point identification method; performing statistical screening on the difference curve peak points of all the measuring points to obtain difference effective peak points, and then screening out curvature effective peak points; performing high-low water level working condition time period interception on the displacement curve, and calculating the displacement difference in the time period; and performing crack early warning according to the change condition of the displacement difference and the historical displacement difference. On the basis of the fiber bragg grating displacement sensing technology, gate crack on-line automatic identification and early warning are achieved.