CN203100972U - A Calibration System of Pre-embedded Bolt Axial Force Sensor - Google Patents

Abstract

The utility model relates to a pre-embedded bolt axial force sensor calibration system, which includes a bolt axial force sensor, an axial force meter, a stretcher and data acquisition equipment: the bolt axial force sensor passes through the axial force meter, and the front end and the axial force sensor The front end of the gauge is offset, and the rear end is connected with the stretching head of the tensioner through screwing; the bolt axial force sensor and the axial force gauge are both connected with the data acquisition equipment. The utility model uses the pre-embedded bolt axial force sensor and axial force meter to simultaneously read the strain and axial force with data acquisition equipment, and obtains the strain-axial force relationship at the same time, effectively solving the mechanical problems of large-scale and high-strength bolts. Performance testing issues.

Description

A Calibration System of Pre-embedded Bolt Axial Force Sensor

technical field

The utility model relates to the technical field of component detection, in particular to a pre-embedded bolt axial force sensor calibration system. the

Background technique

At present, high-strength bolts with larger specifications are often used in wind turbines. For example, the specifications of tower bolts are generally above M36. In recent years, among the tower collapse accidents and operation failures of a large number of wind turbines that occurred during the hoisting of the whole machine and the operation of the wind farm, the failures caused by improper connection of large-scale and high-strength bolts account for a considerable proportion. This seriously affects the safety of wind power equipment. Therefore, the reliability verification of bolts is of great significance and urgent. At present, there is a lack of corresponding products in the axial force test of large-scale high-strength bolts in China, especially the performance test of large-scale pre-embedded bolt axial force sensors in various environments. When testing, large tensile equipment is often required. However, it is more difficult to transform the existing tension system. At present, the method commonly used to calibrate the bolt axial force sensor can only measure the axial force-time relationship and the strain-time relationship, and cannot directly obtain the strain-axial force relationship. the

It can be seen that there are obvious deficiencies and defects in the performance testing equipment and testing methods for large-scale and high-strength bolts in the prior art, and further improvement is urgently needed. The calibration system of the buried bolt axial force sensor is one of the important topics of current research and development. the

Utility model content

The technical problem to be solved by the utility model is to provide a pre-embedded bolt axial force sensor calibration system, so that it can directly obtain the strain-axial force relationship of the bolt, and it is more convenient to perform performance evaluation on large-scale and high-strength bolts in various environments. Tests to overcome the deficiencies of the prior art. the

In order to solve the above technical problems, the utility model provides a pre-embedded bolt axial force sensor calibration system, which includes a bolt axial force sensor, an axial force meter, a tensioner and data acquisition equipment, wherein: the bolt axial force sensor passes through the axial force meter , the front end is offset against the front face of the axial force meter, and the rear end is connected with the stretching head of the tensioner by threading; the bolt axial force sensor and the axial force meter are both connected to the data acquisition device. the

As a further improvement, a spacer is installed between the front end of the bolt axial force sensor and the front end of the axial force meter, or between the axial force meter and the tensioner. the

The hole diameter of the bolt axial force sensor pierced by the spacer is 2-3 mm larger than the outer diameter of the bolt axial force sensor. the

A washer is arranged between the front end of the bolt axial force sensor and the pad or the front end of the axial force gauge. the

The axial force meter adopts a cylindrical axial force meter. the

The threaded length of the bolt axial force sensor and the tensioning head of the tensioner is not less than 1/2 of the nominal diameter of the thread. the

After adopting the above design, the utility model has the following beneficial technical effects compared with the prior art:

The utility model is a pre-embedded bolt axial force sensor calibration system, through the pre-embedded bolt axial force sensor and the axial force meter, the strain and the axial force are simultaneously read by the data acquisition equipment, and the strain-axial force at the same time is obtained The relationship effectively solves the problem of mechanical performance testing of large-scale high-strength bolts. the

The technical solutions of the present utility model will be further described in detail through the drawings and embodiments below. the

Description of drawings

The above is only an overview of the technical solutions of the utility model. In order to understand the utility model more clearly, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. the

Figure 1 is a schematic diagram of the composition of the calibration system of the embedded bolt axial force sensor of the present invention. the

Fig. 2 is the strain-axial force curve diagram that the utility model obtains. the

Detailed ways

Please refer to Fig. 1, a kind of pre-embedded bolt axial force sensor calibration system of the present invention includes bolt axial force sensor 1, axial force meter 3, tensioner 5 and data acquisition equipment, bolt axial force sensor 1 and shaft The wires of the force gauge 3 are all connected with the data acquisition equipment. In addition, the utility model can also include spacers 4 and gaskets 2 . the

The block 4 can be arranged between the axial force meter 3 and the tensioner 5, the bolt axial force sensor 1 passes through the block 4 and the cylindrical axial force meter 3, and the front end is attached to the front end of the block or the axial force meter , the rear end is connected to the tensioner 5, and a washer 2 can be set between the front end surface of the bolt axial force sensor 1 and the axial force meter 3. the

In addition, the axial force meter 3 can also be arranged between the pad 4 and the tensioner 5, the bolt axial force sensor 1 passes through the cylindrical axial force meter 3 and the pad 4, and is connected with the tensioner 5, and can also be A washer is arranged between the bolt axial force sensor and the spacer. the

Wherein, the spacer 4 is a supporting component, which can be a circular spacer, and the spacer can be provided with a calibration system mounting bracket, and its hole diameter is 2-3 mm larger than the outer diameter of the bolt axial force sensor 1 . The bolt axial force sensor 1 is threaded and connected with the stretching head of the tensioner 5, and the threaded length is not less than 1/2 of the nominal diameter of the thread. The axial force meter 3 can be a cylindrical axial force meter as shown in the figure, and different ranges can be selected according to the bolt specifications. For example, M36 bolts have a range of 700kN, and M42 bolts have a range of 900kN. The tensioner is also selected according to the specification of the bolt to be tested. the

When in use, when the parts are in close contact, start to use the manual pump to continuously pressurize the tensioner 5 to 80% of the yield limit load of the tested bolts and unload to 0, so load and unload three times. At the same time, the data acquisition equipment records the test data of the bolt axial force sensor and the axial force meter throughout the process, and generates a curve from the data through the computer. Through the conditions of each curve, the fitting equation of strain-axial force can be obtained, and at the same time, the coincidence of three times of bolt stretching and retraction can be judged. the

Test method 1: Use a manual pump to continuously pressurize the tensioner to 80% of the yield limit load of the bolt and unload it to 0, so load and unload one or more times. During the testing process, the data equipment collects data and draws a graph based on the data to obtain a fitting equation. the

Test method 2: Use a manual pump to continuously pressurize the tensioner to 50% to 90% of the bolt yield limit load and unload it to 0, so load and unload one or more times. During the testing process, the data equipment collects data and draws a graph based on the data to obtain a fitting equation. the

Test method 3: Use a manual pump to continuously pressurize the tensioner to 0% to 90% of the bolt yield limit load and unload it to 0, so load and unload one or more times. During the testing process, the data equipment collects data and draws a graph based on the data to obtain a fitting equation. the

Please refer to Figure 2, and perform the test according to the first test method. During the test, as the tensioner is loaded, a set of corresponding points about the strain and the axial force are collected, and the strain signal is used as the x coordinate. Correspondingly, the current axial force signal is plotted as the y coordinate, and the thick solid line is the connection line of the measured data points. Using regression analysis, a linear equation is fitted, and the correlation coefficient R ² characterizing the dispersion of the point set and the fitting equation, the closer R ² is to 1, indicates that the fitting equation reflects the real strain-axial force of the bolt axial force sensor The error of the function relationship is smaller. This equation is used to convert the output strain signal of the bolt axial force sensor into the axial force on the bolt in the later stage.

The utility model simultaneously reads the strain and the axial force through the data acquisition equipment, and obtains the strain-axial force relationship at the same time, that is, the strain-axial force curve of the high-strength bolt. Through the corresponding relationship between axial force and strain measured by each set of embedded bolt axial force sensor, the coincidence of high-strength bolt stretching and retraction and the load of the bolt in the actual working state are obtained, thus effectively solving the problem of large-scale Mechanical performance test problems of high-strength bolts. the

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model in any form. Those skilled in the art may use the technical content disclosed above to make some simple modifications, equivalent changes or modifications. Within the protection scope of the present utility model. the

Claims (6)

1. A pre-embedded bolt axial force sensor calibration system is characterized in that it comprises a bolt axial force sensor, an axial force meter, a tensioner and a data acquisition device, wherein: The bolt axial force sensor passes through the axial force meter, the front end is against the front face of the axial force meter, and the rear end is connected with the stretching head of the tensioner by threading; Both the bolt axial force sensor and the axial force meter are connected with the data acquisition equipment. 2. The embedded bolt axial force sensor calibration system according to claim 1, characterized in that: between the front end of the bolt axial force sensor and the front end of the axial force meter, or between the front end of the axial force meter Pads are installed between the stretcher and the stretcher. 3. The pre-embedded bolt axial force sensor calibration system according to claim 2, characterized in that: the hole diameter of the bolt axial force sensor pierced by the spacer is 2-3 mm larger than the outer diameter of the bolt axial force sensor. 4. The embedded bolt axial force sensor calibration system according to claim 2, characterized in that a washer is arranged between the front end of the bolt axial force sensor and the pad or the front end of the axial force gauge. 5. The embedded bolt axial force sensor calibration system according to claim 1, characterized in that: the axial force meter is a cylindrical axial force meter. 6. The pre-embedded bolt axial force sensor calibration system according to claim 1, characterized in that: the screwing length of the bolt axial force sensor and the tensioning head of the tensioner is not less than 1 of the nominal diameter of the thread /2.

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