CN203116893U - Hidden weld joint stress monitoring device for orthotropic steel bridge decks - Google Patents

Abstract

The utility model discloses a stress monitoring device for concealed welding seams of orthotropic steel bridge decks, which includes a data measurement module and an optical fiber strain sensor arranged along the edge of the U rib of the orthotropic steel bridge deck and the weld seam connecting the bridge deck. The optical fiber strain sensor is provided with a temperature tester; the data acquisition module responds to the data acquisition instruction to launch the excitation signal of the data measurement module, and collects the data measured by the data measurement module into valid data; the data processing module sends the data to the data acquisition module Sending a data acquisition command, receiving the effective data converted by the data acquisition module, calculating the stress value of the weld according to the effective data and outputting it for display. The utility model adopts an integral measurement method, which can directly reflect the stress state of the concealed weld seam of the orthotropic steel bridge deck, and the sensor integrated temperature tester can effectively correct the influence of temperature on the test, effectively reduce the risk of sensor damage during construction, and ensure test data More accurate without being affected by temperature.

Description

An Orthotropic Steel Bridge Deck Concealed Weld Stress Monitoring Device

technical field

The utility model belongs to the technical field of weld seam testing of steel structures, in particular to a stress monitoring device for hidden weld seam of orthotropic steel bridge decks.

Background technique

my country has become a big country of cable-stayed bridges and suspension bridges in the world. Orthotropic steel bridge decks are widely used in long-span bridges in my country. With the increase of service life and traffic flow of such bridges, the fatigue of steel bridge decks under repeated complex load cycles The problem of damage has become increasingly prominent. After long-term operation, fatigue cracks and damages have appeared in different degrees on the domestic orthotropic steel bridge deck, which has caused great harm to the normal operation of the bridge.

As a closed structure prefabricated in factories, orthotropic steel bridge decks have many hidden welds, which are difficult to monitor and control by general means. In the process of use, hidden welds may be damaged, and these damages are often characterized by complexity, concealment, difficulty in repair, and catastrophic consequences, which have become one of the difficult problems restricting the management and maintenance of steel bridge deck structures.

Since the 1950s, the importance of bridge health monitoring has been gradually recognized, but due to the limitations of relatively backward detection and monitoring methods, its application has not been promoted and paid attention to. In recent years, with the softness of long-span bridges and the complexity of form and function, this technology has become a research hotspot in the industry. Many countries have tried and explored on some long-span bridges that have been built and are under construction, and have formed a variety of monitoring technologies suitable for weld stress in steel structures, including: X-ray method, ultrasonic method, magnetic method, electrical resistance measurement method, photoelasticity method and optical fiber measurement method, etc.

The X-ray method is a traditional detection method, which uses the principle of diffraction when X-rays penetrate the metal lattice, and measures the strain of the surface layer of the metal material or component due to the change of the lattice spacing, thereby calculating the stress. The X-ray method can non-destructively measure the stress or residual stress in the component, and is especially suitable for measuring the stress distribution of thin layers and crack tips. When measuring stress with X-rays, its accuracy is affected by many factors, such as the structure of the material to be tested, the degree of fine deterioration of grains, the selection of diffraction surfaces, the wavelength of X-rays, the measurement method used, and the surface of the tested piece. The smoothness and processing conditions, etc., but the measurement depth is only tens of microns, and the detection equipment is complicated, so it is inconvenient to test on site.

The ultrasonic method is to measure the size of the internal stress by accurately measuring the propagation speed of the ultrasonic wave in the material. It is characterized by short measurement time and light instrument. It can measure both surface stress and internal stress. However, like the X-ray method, there are many factors that affect its measurement accuracy. Among them, the coupling between the measurement device and the specimen is an important question.

The magnetic coupling stress detection method of iron and steel materials is to measure the magnitude and direction of the stress by measuring the change of the internal magnetic properties of the steel material structure and using the coupling relationship between it and the stress, so as to realize non-contact stress detection. However, this method is still in the research and exploration stage for different stress states, cross-sectional forms of different components, size effects, steel grades (such as Q345, Q390, Q420, etc.), and the law of changes in stress to its magnetic properties.

That is, the resistance strain gauge measurement method is the most widely used and most developed measurement method. E. Simmons et al. (1938) produced the first batch of practical paper-based wire-wound resistance strain gauges. P. Jackson (1953) used photolithography technology to make a foil strain gauge for the first time. C.S Smith (1954) discovered the piezoresistive effect of semiconductor materials, and W.P Mason (1957) developed semiconductor strain gauges, whose sensitivity coefficient is more than 50 times higher than that of metal wire strain gauges. Its principle is to measure the surface strain with a resistance strain gauge, and then determine the surface stress state of the component according to the relationship between stress and strain. Fix the resistance strain gauge on the component under test, and when the component is deformed, the resistance of the resistance strain gauge will change accordingly. Measure the change of this resistance with a resistance strain gauge, and after conversion, the measured stress or strain can be obtained.

David Brest (1816) found that transparent glass has a temporary birefringence effect when it is stressed, which laid the foundation for the development of photoelasticity. In the early 20th century, E.G Cocker and L.N.G Phelan used the photoelastic method to study the stress distribution of bridge structures. The photoelastic method is to place the structural model made of transparent plastic with birefringence effect in the polarized light field. When the model is loaded, the interference pattern generated on the model can be seen, and the interference fringes are measured. Through calculation, The stress state of the structural model under load can be determined. The experimental method of using this optical principle to study elastic mechanics is called photoelasticity. The photoelastic method can be used to study the stress distribution of engineering components with complex geometric shapes and loading conditions, especially the stress concentration area and three-dimensional internal stress.

Optical fiber sensor is a sensor with light as the transmission medium of information and light as the information carrier. Since the beginning of fiber optic sensor research in the mid-1970s, fiber optic sensor technology has developed rapidly, and it has been proved that fiber optic sensors can be applied to displacement, vibration, strain, temperature, pressure, bending, speed, acceleration, current, rotation, magnetic field, voltage, flow , concentration and so on nearly a hundred physical quantity measurements. These advantages make the fiber Bragg grating develop rapidly. Optical fiber (Bragg) grating sensing technology is becoming more and more mature. In the past 20 years, fiber grating sensor technology has been widely used in aerospace industry, shipbuilding industry, electric power, large construction, bridge engineering, nuclear industry, petrochemical industry, water conservancy, mining industry, municipal engineering, medicine and other fields. However, due to the small transverse dimension of welds in steel structures, and the surface is not suitable for grinding and other treatments, it is difficult to directly monitor the stress of welds with optical fibers.

The existing above-mentioned contact measurement methods including strain gauges all have the influence on the steel structure weld structure during the installation process, and are easily damaged during the installation and post-test process, and the reliability and durability of the test The disadvantage of low sex. The existing technology is not suitable for the stress monitoring of the concealed welds of orthotropic steel bridge decks, and the sensor structure is relatively simple, and the influence of temperature on the sensor test results is not considered, which will cause large errors in the data test results due to temperature changes. It is difficult to meet the requirements of engineering testing and does not have significant advantages.

Utility model content

The purpose of this utility model is to provide a kind of stress monitoring of the concealed weld seam of orthotropic steel bridge deck. The actual stress of the weld seam is acquired by the stress state, which avoids the problem that the sensor has an influence on the weld seam structure itself during the installation process of the current test sensor.

In order to achieve the above object, the utility model adopts the following technical solutions:

An orthotropic steel bridge deck concealed weld stress monitoring device, comprising:

The data measurement module includes an optical fiber strain sensor for measuring the stress change data of the weld arranged along the edge of the weld seam connecting the U-rib of the orthotropic steel bridge deck and the bridge deck. and a temperature tester for the temperature value in the optical fiber strain sensor;

The data acquisition module is used to respond to the data acquisition instruction to transmit the excitation signal for the work of the data measurement module, collect the data measured by the data measurement module and convert it into valid data;

The data processing module is configured to send the data collection instruction to the data collection module, receive the valid data converted by the data collection module, calculate the stress value of the weld according to the valid data, and output and display it.

The optical fiber strain sensor includes a housing, an optical fiber signal transmission line, an effective test unit connected to the optical fiber signal transmission line in the housing, and the temperature tester placed on one side of the effective test unit.

The optical fiber signal transmission line adopts shielded optical fiber.

The data acquisition module includes:

The collector is used to respond to the data collection instruction, process the collection instruction and send it to the signal trigger, receive the data measured by the data measurement module, process it into valid data, and input it to the data processing module;

The signal trigger is used to receive the instruction sent by the collector, process it, return to the collector, send it to the data measurement module, and stimulate the data measurement module.

The collector includes a master controller, a signal calculator connected to the master controller for calculating and processing the induction signal into valid data and inputting it into the master controller, and a signal calculator connected to the signal calculator An inductive signal device for receiving the data measured by the data measuring module and transmitting it to the signal calculator.

The main controller includes a central controller, a signal converter connected to the central controller for recognizably converting the effective data calculated and processed by the signal calculator into the data processing module, and a signal converter for An excitation controller controlling the signal exciter.

The signal trigger includes an excitation transmitter, a signal output circuit connected to the excitation transmitter, an excitation signal storage converter, a positive circuit connected to the excitation signal storage converter, a control circuit, and the excitation transmitter and Ground circuit for excitation signal storage converter.

The data processing module is a computer.

The computer is a portable computer.

Compared with the prior art, the utility model has the following characteristics and beneficial effects:

The utility model provides a test device for the concealed weld stress in the orthotropic steel bridge deck which is difficult to know, and can solve the difficulty in testing the concealed weld stress by arranging optical fiber strain sensors around the structural concealed weld problems; since the installation of the optical fiber strain sensor does not touch the weld, it can effectively reduce the risk of the sensor being damaged during the construction and use of the actual structure, and avoid the influence of the sensor installation on the weld structure. Compared with the existing contact strain sensor The test methods such as chip and grating sensor can effectively improve the test ability and service life of the optical fiber strain sensor. In addition, through the built-in temperature tester in the optical fiber strain sensor, the data acquisition can simultaneously test the measured member (weld) and the optical fiber strain sensor. Temperature correction is performed on the test results, which effectively eliminates the huge influence of the test results by temperature changes and ensures the accuracy of the test data.

Description of drawings

Fig. 1 is a structural schematic diagram of an orthotropic steel bridge deck concealed weld stress monitoring device provided by an embodiment of the present invention;

Fig. 2 is a system block diagram of an orthotropic steel bridge deck concealed weld stress monitoring device provided by the utility model;

Fig. 3 is a schematic structural diagram of a signal exciter provided by an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a sensor provided by an embodiment of the present invention;

Fig. 5 is a weld seam stress test data diagram provided by the embodiment of the present invention;

Fig. 6 is a flow chart of the test method detection part of the orthotropic steel bridge deck concealed weld stress monitoring device provided by the embodiment of the present invention;

In the figure: 1-optical fiber strain sensor, 2-collector, 3-signal exciter, 4-data processing module, 5-protective shell, 6-positive circuit, 7-control circuit, 8-ground circuit, 9-signal output Circuit, 10-optical fiber signal transmission line, 11-housing, 12-effective test unit, 13-temperature tester.

Detailed ways

The substantive features and advantages of the present invention will be further described below in conjunction with examples, but the present invention is not limited to the listed embodiments.

The hidden weld stress monitoring device of the orthotropic steel bridge deck in the utility model mainly obtains the weld seam stress by converting the steel plate stress around the weld seam of the orthotropic steel bridge deck.

Referring to Figures 1 to 3, an orthotropic steel bridge deck concealed weld stress monitoring device includes:

The data measurement module includes an optical fiber strain sensor for measuring the stress change data of the weld arranged along the edge of the weld seam connecting the U-rib of the orthotropic steel bridge deck and the bridge deck. and a temperature tester for the temperature value in the optical fiber strain sensor;

The data acquisition module, the signal input end is connected with the signal output end of the data measurement module, and is used to respond to the data acquisition instruction to transmit the excitation signal for the work of the data measurement module, and collect the data measured by the stress acquisition module and convert it into an effective data;

A data processing module, the signal input terminal is connected to the signal output terminal of the data acquisition module, and is used to send the data acquisition instruction to the data acquisition module, receive the effective data converted by the data acquisition module, and The effective data is used to calculate the stress value of the weld and output it for display.

In the embodiment of the utility model, the data collection module receives and responds to the command of the data processing module through the 485 communication interface, and feeds back the collection result to the data processing module.

4, the optical fiber strain sensor 1 includes a thin cylindrical shell 11, an optical fiber signal transmission line 10 drawn from two ends of the shell 11, an effective test unit 12 and a temperature tester 13; the effective test unit 12 is located at the axial center of the cylindrical shell 11 of the sensor 1, and the shell 11 and the effective test unit 12 are fixed by a colloidal material with a certain strength. The temperature tester 13 is built in the sensor 1, and the temperature tester 13 is a cylinder, which is fixedly installed on the side of the effective test unit 12 of the sensor 1 by glue; the optical fiber signal transmission line 10 adopts an optical fiber shielded line, connects the effective test unit 12 and the temperature tester 13 inside the sensor 1, and is connected with the data acquisition module connect.

During the test, the optical fiber strain sensor 1 is arranged along the edge of the weld seam connecting the U-rib of the orthotropic steel bridge deck and the bridge deck, that is, it is distributed along the length direction of the weld seam adjacent to the weld seam.

Referring to shown in Fig. 1-2, in the utility model embodiment, described data collection module comprises:

The collector 2 is connected with the sensor 1 through the optical fiber signal transmission line 10, and is used to respond to the data collection instruction, process the collection instruction and send it to the signal exciter, and receive the data measured by the data measurement module processed into valid data and input to the data processing module;

The signal trigger 3 is connected with the collector 2, and is used to receive the command sent by the collector 2, process it, return to the collector 2, send it to the data measurement module, and stimulate the data measurement module.

Referring to Fig. 2, in the embodiment of the present utility model, the collector 2 includes a master controller, which is connected to the master controller and is used to calculate and process the induction signal into valid data and then input it into the master controller. The signal calculator of the instrument and the inductive signal instrument connected to the signal calculator for receiving the data measured by the data measurement module and transmitting to the signal calculator.

Referring to Fig. 2, the main controller includes a central controller, and a device connected to the central controller for inputting the valid data calculated and processed by the signal calculator into the data processing module after identifiable conversion. A signal converter and an excitation controller for controlling the signal exciter to emit excitation signals.

Described signal exciter 3 comprises excitation transmitter, the excitation signal storage converter that is connected with described excitation transmitter; Described excitation transmitter connects described annunciator, excitation controller respectively; Described excitation signal storage converter is connected with The excitation controller is connected.

Referring to Fig. 3, the signal trigger 3 has a protective case 5, the excitation transmitter and the excitation signal storage converter are placed in the protective case 5, and a positive circuit 6 and a control circuit for signal excitation are provided. 7. Grounding circuit 8 and signal output circuit 9; the positive circuit 6 and control circuit 7 are connected to the signal storage converter, and the signal output circuit 9 is connected to the excitation transmitter. The excitation transmitter is connected to the positive circuit 6, the excitation transmitter is connected to the positive circuit 6 and the control circuit 7, and the excitation transmitter is connected to the grounding circuit 8 to form a loop.

In the embodiment of the utility model, the data processing module is a built-in corresponding data processing device, which can analyze and process the data collected by the data acquisition module, so as to obtain the stress value of the weld seam and display it computer4.

Preferably, the computer 4 is a portable computer.

When working, first the data processing module sends data acquisition instructions to the data acquisition module, the main controller in the data acquisition module controls the signal exciter through the excitation controller to transmit the excitation signal to the data measurement module through the collector, and the optical fiber strain sensor of the data measurement module The internal effective test unit begins to feel the stress change of the weld, converts the stress change result into an induction signal, and returns the induction signal to the collector of the data acquisition module, and the signal data collected by the induction signal device and signal calculator of the collector The signal is transmitted to the main controller, and the signal is converted by the signal converter of the main controller, and then sent to the data processing module for processing.

The orthotropic steel bridge deck concealed welding seam stress monitoring device described in the embodiment of the utility model, when the optical fiber strain sensor is placed next to the welding seam for measurement, the stress at the edge of the welding seam is tested, and after conversion, it is converted into the stress of the welding seam. The conversion formula is as follows:

                                                 

为换算获得的焊缝应力数据，

为传感器测试数据，K、C为对传感器获得的数据换算成焊缝应力的换算公式，其中，K为换算系数， C为换算常数。  In the formula,

In order to convert the obtained weld stress data,

is the sensor test data, K and C are the conversion formulas for converting the data obtained by the sensor into weld stress, where K is the conversion coefficient and C is the conversion constant.

The temperature in the weld seam and the optical fiber strain sensor is measured by the temperature tester 13 in the optical fiber strain sensor to eliminate the influence of temperature on the sensor data. The temperature correction formula has the form:

 

为测量时温度，为标定时采用的温度，  

为计算温度下的采集数据修正增量， 

为温度修正系数，根据传感器的特征进行温度标定试验确定。 In the formula,

is the temperature at the time of measurement, The temperature used for calibration,

Correct the increments for the acquired data at the calculated temperature,

is the temperature correction coefficient, which is determined by the temperature calibration test according to the characteristics of the sensor.

Referring to Fig. 6, according to the above principles, the specific steps of the utility model for testing the weld stress of the orthotropic steel bridge deck are as follows:

Step 1, Calibrate the test sensor: Install the sensor on the surface of the calibration test piece, stretch the test piece, and establish the sensor calibration formula according to the actual stress of the test piece and the data returned by the sensor;

Step 2, install the sensor: install the sensor in the construction of the bridge structure, and install the sensor at 2cm from the edge of the weld;

Step 3, test data: After the sensor is installed, the sensor data can be collected, including the effective test unit data and temperature test data of the sensor;

Step 4, calculate the stress value of the weld seam, and calculate and obtain the stress value of the weld seam according to the calibrated sensor formula.

specific embodiment

According to steps 1~3, after processing by the collector of the data acquisition module, the stress value of the sensor is 15.73MPa, and the temperature test value is 19.5°C, and the stress value of the sensor is transmitted to the data processing module, and the data processing module uses the formula obtained in step 1 , the calculated weld stress value is 23.14MPa. In the same way, from multiple measuring points on the edge of a weld, the stresses of each measuring point on the weld are collected and calculated as 21.81MPa, 23.14MPa, 25.26MPa, and 22.39MPa.

The utility model provides a test device for the concealed weld stress in the orthotropic steel bridge deck which is difficult to know, and can solve the difficulty in testing the concealed weld stress by arranging optical fiber strain sensors around the structural concealed weld problems; since the installation of the optical fiber strain sensor does not touch the weld, it can effectively reduce the risk of the sensor being damaged during the construction and use of the actual structure, and avoid the influence of the sensor installation on the weld structure. Compared with the existing contact strain sensor The test methods such as chip and grating sensor can effectively improve the test ability and service life of the optical fiber strain sensor. In addition, through the built-in temperature tester in the optical fiber strain sensor, the data acquisition can simultaneously test the measured member (weld) and the optical fiber strain sensor. Temperature correction is performed on the test results, which effectively eliminates the huge influence of temperature changes on the test results and ensures the accuracy of the test data.

Claims (9)

1. the hidden weld stress monitoring device of Orthotropic Steel Bridge Deck is characterized in that, comprising:

Data measurement module, comprise along the fibre optic strain sensor for the STRESS VARIATION data of measuring weld seam of the edge placement of Orthotropic Steel Bridge Deck U rib and decking attachment weld, be provided with in the described fibre optic strain sensor for the temperature tester of measuring the temperature value in weld seam and the described fibre optic strain sensor;

Data acquisition module is used for the pumping signal that the response data acquisition instructions is launched described data measurement module work, gathers the data-switching that described data measurement module records and becomes valid data;

Data processing module is used for sending described data acquisition instruction to described data acquisition module, receives the described valid data of described data acquisition module conversion, and stress value and the output of calculating described weld seam according to described valid data show.

2. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 1, it is characterized in that, described fibre optic strain sensor comprises shell, fiber-optic signal transfer line, the Validity Test unit that is connected with described fiber-optic signal transfer line in described shell and the described temperature tester that places described Validity Test unit one side.

3. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 2, it is characterized in that described fiber-optic signal transfer line adopts shielding optical fiber.

4. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 1, it is characterized in that described data acquisition module comprises:

Collector is used for the described data acquisition instruction of response, is emitted to the signal excitation device after described acquisition instructions is handled, and the induced signal that receives described data measurement module output is processed into valid data and is input to described data processing module;

The signal excitation device is emitted to described data measurement module for being back to described collector after the instruction process that receives described collector emission, excites described data measurement module.

5. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 4, it is characterized in that described collector comprises that master controller, being used for of being connected with described master controller carry out computing to described induced signal and become the calculated signals device of the described master controller of input behind the valid data and being used for of being connected with described calculated signals device to receive the induced signal device that described induced signal that described stress sensing module exports is passed to described calculated signals device.

6. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 5, it is characterized in that described master controller comprises that central controller, being used for of being connected with described central controller carry out the valid data that described calculated signals device computing becomes can identify the signal converter of the described data processing module of conversion back input and the excitation controller that is used for the described signal excitation device of control.

7. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 4, it is characterized in that described signal excitation device comprises the grounding circuit of stimulated emission device, the signal output apparatus that is connected with described stimulated emission device, pumping signal storage converter, the cathode circuit that is connected with described pumping signal storage converter, control circuit and described stimulated emission device and pumping signal storage converter.

8. according to the hidden weld stress monitoring device of the described Orthotropic Steel Bridge Deck of claim 1, it is characterized in that described data processing module is a computing machine.

9. the hidden weld stress monitoring device of described Orthotropic Steel Bridge Deck according to Claim 8 is characterized in that described computing machine is portable computer.

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