[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to better understand the invention and can be implemented, but the embodiments are not limited thereto.
[0044] Refer figure 1 As shown, an embodiment of the bridge is measured when the bridge is measured, including the pulley 1 and the fiber grating displacement force, and one end of the wire is fixed at the bottom of the bridge, and the other end of the pull line is The detection end of the fiber grating displacement is fixed, and the optical fiber grating displacement is mounted on the angle pad 3, and the angle spacer is fixed to the vertical support portion 4 of the bridge, the fiber grating displacement is connected to the fiber grating demodulator 5. The fiber grating demodulator collects data and supplies computer 6.
[0045] In use, first, according to the installation angle determined according to the on-site installation environment, determine the mounting position of the angle mass and the mounting position of the angle space block according to the mounting angle, and then mounted the angle pad on the vertical support. The vertical support portion may be a pier. After mounting, the fiber grating displacement is fixed to the vertical support, and then the wire is mounted, the pulley is fixed at the point position, and the other end is fixed to the detection end of the fiber grating displacement. It can be fixed to welding, ensuring the firmness of the outdoor use, the above-described wire, the mounting order of the fiber grating displacement, and angular mass, can be adjusted according to the actual situation;
[0046] After the installation, the fiber grating demodulator is fixed to the pier, and the collected data can be transmitted to the computer record by the jumper and the fiber grating displacement meter, and then the computer can be transmitted to the computer record. To displacement to achieve effective monitoring purposes and effects. The above device has a simple structure, easy to install, no need to set a platform, there is no problem with falling risk, and will not affect the limit, safe and reliable, stability.
[0047] The above drawn wire is a steel wire, and the specific indium steel can be used to satisfy the use requirements to ensure stability during the measurement process. The cable is welded to the detection end of the fiber grating displacement and ensures verticality, reducing the detection error. In order to facilitate the fixing of the wire, the fixture can be provided at the test point, the cable is connected to the fixture, and the fixing member can be an expansion screw for easy operation.
[0048] Refer figure 2 and image 3As shown, the apparatus can also be used in the laboratory, to perform analog monitoring, in order to facilitate adjustment of the angle angle, the above-described angle spacer is designed as an angular triangular bracket, and the triangular bracket is used in indoor laboratory. The rapid adjustment measurement at the angle, the triangular bracket includes the L-type body 8 and the adjustment arm 9, and the upper end portion of the adjustment arm is connected to the vertical segment of the L-shaped body, and the adjustment arm is adjacent to the other end. A long round hole 11, the first adjustment long round hole, the lateral section surface of the L-type body, the first conditioning long round hole 12, the first adjustment long-circular hole, and the second adjustment long circular hole forming the X structure and through the hand transmitting bolt assembly 13 is fixed, the adjustment arm surface also provides a third long circular hole 14 for mounting the fiber grating displacement.
[0049] In order to verify the accuracy of the experimental data, a laser displacement is also designed, the laser displacement is used for experimental verification, and the laser displacement is placed in the measurement vertical displacement below the measurement point. During the experiment, the mass block is also required, and the mass block provides gravity for the bridge, and the bridge bearer is loaded.
[0050] The present invention also discloses a bridge-based signal-based monitoring method, which uses the above-described monitoring device, which requires calibration and temperature compensation for the fiber grating displacement before the field installation, to ensure fiber grating displacement Measurement accuracy;
[0051] Among them, in order to obtain the relationship between the cable displacement and the center wavelength, the laboratory calibration is performed. In the calibration test, the calibration test of the three sets of positive-reverse strokes was performed on a constant temperature and humidity, and the positive stroke was increased to the maximum range of 50 mm, and the amount of change in the stretch was 5mm. The center wavelength values corresponding to the stabilization of the stabilization of the stabilization were recorded using the fiber grating demodulator. In contrast to the forward stroke test, from the maximum number of times to the initial position, such as Figure 4 The calibration coefficient of the fiber grating displacement is obtained;
[0052] The fiber grating displacement test internal sensor is very high, and the temperature change can cause the sensor center wavelength of the sensor, which will affect the displacement of the optical fiber grating displacement, for this set of test devices, the temperature mainly affects the fiber grating displacement Therefore, it is necessary to perform temperature correction for the fiber grating displacement. Place the fiber grating displacement into the constant temperature and humidity test chamber to study the effect of ambient temperature on the center wavelength of the fiber grating displacement, the ambient temperature change ranges from 0 to 40 ° C, with a temperature change amount at 5 ° C, using the demodulation instrument and computer The sensor center wavelength is acquired, and the function relationship between the center wavelength and the temperature is fitted to obtain the temperature coefficient of KT. Figure 5 Indicated;
[0053] Using the following formula: ΔL = 0.12609 (W-W0 ± ± ±WT)
[0054] ΔWt = KT (T-T0)
[0055] The calibration and temperature compensation of the fiber grating displacement is completed; ΔL in the formula is a displacement change; W is the current center wavelength of the fiber grating displacement; W0 is the initial center wavelength of the fiber grating displacement; wherein T0 is the initial temperature; T is The temperature value during the measurement; KT is the temperature coefficient;
[0056] For the bridge under central load, the deformation graph is Image 6 As shown, it is assumed that the bridge is at the angle θ of the bottom of the bridge during the lower process. 0 = Θ 1 , Uniformly remember θ before and deformation, according to the geometric relationship, the ratio K between the vertical displacement of the laser displacement measurement and the oblique displacement of the intrinsic displacement of the cartridge system satisfies the following formula:
[0057]
[0058] Where L 0 In order to reduce the initial length of the front pulley; 1 In order to the length of the rear pull line; ΔH is the vertical displacement change amount measured by the laser displacement meter; ΔL is the inclined displacement change amount measured by the intrinsic system; θ is an angle of the bridge bottom and the pulley; k is the laser displacement measurement The ratio between vertical displacement changes and oblique displacement measured by the intrinsic system;
[0059] The inclination θ has a small change in the bridge during the lower process, and this scheme is mainly by changing the inclination angle at the bottom of the cable and the bridge, and the inclination angle is evaluated to measure the vertical displacement, and the vertical displacement and oblique displacement are obtained. Correction relationship. Therefore, a valid test is required. Under the same test conditions, different pull angles are changed and concentrated in the test beam spans, and the initial angle θ is 30 °, 40 °, 50 °, 60 °, 70 as needed. ° and 80 ° indoor test conditions, using the laser displacement meter measurement test beam sprocket, and the set of monitoring devices measure the oblique displacement of the measuring point; specifically, the fiber grating displacement is pulled One end is fixed, the other end of the pulley is fixed at the measurement point position of the bottom of the test beam, and the optical fiber grating displacement is fixed to the vertical support of the test beam, the initial clip selected in the drawing of the test case. The angle is fixed below the test point. Under each working condition, three repetitions were made, and the measured ratio K between vertical displacement and oblique displacement at different angles, such as Figure 7 Indicated.
[0060] As the increasing angle θ is increasing, the measured ratio K is gradually reduced, and the characteristics of the formula are met. However, the above formula needs to be corrected, and the tilting angle θ is taken into account in consideration of the minute changes in the lower process, fitting the functional measurement ratio K and the inclination angle θ under different tilt angles θ, such as Figure 8 As shown, the fit ratio K1 is obtained:
[0061]
[0062] The ΔH is a vertical displacement; ΔL is the oblique displacement; θ is the angle between the cable and the bottom of the bridge; K1 is the fitting ratio of vertical displacement and oblique displacement;
[0063] After the fitting is completed, according to the on-site system installation, the value of the angle θ at the on-site installation is determined, the root real measurement value K and the inclination angle θ, determines the corresponding fit ratio K1;
[0064] On the spot, the monitoring device is mounted on the bridge of the bridge, and the data of the oblique displacement of the on-site bridge is measured in real time, and the corresponding fit ratio K1 is measured, and the vertical displacement of the field bridge is calculated, realistic The purpose of monitoring.
[0065] Among them, when fitting the function relationship between the measured ratio K and the angle θ, for the convenience of the experiment, see the choice of a big point, and the smaller the inclination in the actual project, the better, convenient to install, safe, so you need to be small Determine the feasibility of the system under the angle of the angle and its measurement accuracy.
[0066] Specifically, in the fixed mounting of the field monitoring device, the less the inclination is, the more easily find the fixed mounting point, and more in line with the actual situation of the site. The purpose of laboratory verification is to compare the vertical displacement measurement data obtained by the induction system and the laser displacement at different small angles, and use a laser displacement to accurately measure, and the vertical movement of the monitoring device and the laser displacement The maximum absolute error between displacements is evaluated as measurement accuracy based on the fiber grating displacement monitoring device.
[0067] Each of the angles is made three times, and the monitoring device and the laser displacement are recorded, the vertical displacement of the test beam across the different small angle increases changes, such as Figure 9 The result shown is the result of the three repetition tests. It is known that the displacement measured by the two means has a good consistency, and the angle is within 15 °, the average absolute error of the three tests at each loading point is within 0.25 mm. And the range of variation is relatively stable, however, when the angle is 10 °, the average absolute error of the three repetition tests is significantly higher than that of the other three angles, and is substantially 0.3mm or more, indicating the accuracy of the monitoring device when the angle is less than 10 °. Limited, as the angle gradually decreases, the absolute error of the monitoring device gradually increases, so that the minimum value of the angle θ can be determined.
[0068] The above embodiments are merely illustrative of the preferred embodiments of the present invention, and the scope of the invention is not limited thereto. Those skilled in the art will be within the scope of the invention on the scope of the invention. The scope of protection of the present invention is subject to the claims.
