CN106404233A - Coercive force-based crane wheel pressure testing method - Google Patents

Abstract

The present invention discloses a coercive force-based crane wheel pressure testing method. An excitation coil and a detection coil are wound on an U-shaped probe; the U-shaped probe is arranged on a side surface of a track; the excitation coil is excited through using an alternating current excitation mode; the track generates a hysteresis loop under the effect of an excitation electric field; the detection coil detects the hysteresis loop through using a sinusoidal signal mode, so that a complete hysteresis loop can be obtained; and detected magnetic field signals are converted into electric signals through a digital-analog converter; and a corresponding relation between pressure and the measured electric signals is calibrated through testing, so that judgment can be realized. The testing method of the invention is based on a coercive force; the excitation coil and the detection coil are used in combination; the magnetic field is generated through using the alternating current excitation mode; the electric signals are generated through using the change of the magnetic field; measurement and calibration are performed according to the electric signals; and therefore, wheel pressure can be measured accurately. The method has the advantages of high test efficiency and accurate measurement.

Description

A test method for crane wheel pressure based on coercive force

technical field

The invention relates to the field of pressure testing, in particular to a coercivity-based crane wheel pressure testing method.

Background technique

The wheel pressure of the crane is an important parameter of the crane, and it is also the main design load and basis of the industrial plant and the track foundation of the cart. The wheel pressure is calculated by the designer based on the crane's lifting capacity, self-weight, span, position of the moving trolley, etc., using balance conditions. In order to simplify the calculation, it is considered that the wheel pressure of each wheel on the same track is uniformly distributed, and only the average maximum wheel pressure under the most unfavorable working conditions is given. At present, most cranes adopt a four-point structure. This arrangement has good symmetry and manufacturability, and has high stability. The wheel pressure distribution of the structure is statically indeterminate, and it is difficult to accurately calculate the actual pressure (wheel pressure) on each fulcrum. Moreover, the distribution of wheel pressure is also related to the rigidity of the structure and foundation, the manufacturing accuracy of the structure, and the flatness of the track, so it is difficult to achieve accurate calculation.

With the needs of the logistics industry and the continuous development of economic construction, the number of cranes has increased rapidly, and the tonnage requirements have also continued to increase. Cranes are developing in the direction of large-scale, high-efficiency and heavy-duty. In order to accurately control the wheel pressure of crane wheels, more and more wheels are installed, so the accurate calculation of wheel pressure is more difficult. However, there is no uniform and accurate measurement method for measuring the wheel pressure of a crane at present, and the present invention provides an accurate and efficient measurement method.

Contents of the invention

The purpose of the present invention is to provide a coercivity-based crane wheel pressure test method to solve the problems raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A coercivity-based crane wheel pressure test method, the steps are as follows:

(1) Wind the excitation coil and detection coil on the U-shaped probe, place the U-shaped probe on the side of the track, excite the coil through AC excitation, and generate a magnetic field. The coil uses a sinusoidal signal to detect the hysteresis loop to obtain the completed hysteresis loop;

(2) The detection system converts the detected magnetic field signal into an electrical signal through a digital-to-analog converter;

(3) Calibrate the corresponding relationship between the pressure and the measured electrical signal through the test, and use a linear curve to describe the corresponding relationship;

(4) Carry out test calibration on the force-signal curve of the entire test system, the calibration is as follows: according to a given force value, measure the magnitude of the magnetic field signal generated by it, measure multiple sets of data, and judge its linear relationship.

As a further solution of the present invention: in the step (1), the excitation coil generates a working magnetic field by applying alternating current.

As a further solution of the present invention: in the step (4), the given force value is determined by a material testing machine or a force applying device.

Compared with prior art, the beneficial effect of the present invention is:

The test method of the present invention is based on the coercive force, combined with the excitation coil and the detection coil, uses the AC excitation method to generate a magnetic field, and uses the change of the magnetic field to generate an electrical signal, and then measures and calibrates according to the electrical signal, thereby accurately measuring wheel pressure, so the present invention has the advantages of high testing efficiency and accurate measurement.

Description of drawings

Fig. 1 is a linear relationship diagram between test signal and calibration force value in the method of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example

The steps of crane wheel pressure test based on coercive force are as follows:

(1) The excitation system adopts the AC excitation method, and at the same time selects the sinusoidal signal as the excitation source to obtain the completed hysteresis loop;

Wind the excitation coil and detection coil on the U-shaped probe, place the probe on the side of the track, excite the coil through AC excitation, and generate a magnetic field, the track will generate a hysteresis loop under the action of the excitation magnetic field, and the detection coil adopts a sinusoidal signal mode Detect hysteresis loop;

The AC excitation method is to generate a working magnetic field by applying an alternating current to the excitation coil. The specific method is: connect the coil, turn on the power supply, apply an alternating current, and excite the coil to generate a magnetic field. Conducive to the stable output of the detection signal;

The sinusoidal signal is used because it is the simplest signal wave and is the most widely used. In order to obtain a complete hysteresis loop, a sinusoidal signal is used;

The excitation coil is to generate a magnetic field by applying an AC power supply to it, and magnetize the ferromagnetic material (here, the track), which belongs to the magnetic field magnetization track; the detection coil is to check the change of the hysteresis loop after the ferromagnetic material is magnetized, to reflect the The change of the stress belongs to the change of the measurement hysteresis loop;

(2) The detection system converts the detected magnetic field signal into an electrical signal through a digital-to-analog converter;

(3) Calibrate the corresponding relationship between the pressure and the measured electrical signal through the test, and use a linear curve to describe the corresponding relationship;

(4) Carry out test calibration for the curve between the "force-signal" of the entire test system,

Calibration steps: According to the given force value, measure the magnitude of the magnetic field signal generated by it, measure multiple sets of data, and judge its linear relationship, so as to calibrate; the given force value is applied by a material testing machine or other force-applying devices , while the material testing machine is used to determine the specific value of the force value.

The specific formulas and graphs need to be determined according to the specific calibration. Examples are as follows:

Determine the two-dimensional X-Y curve (X-signal value; Y-calibration force value) according to the test signal and the calibration force value, measure the signal size X according to the given force value Y, and make one-to-one correspondence, and use the least square method to fit the curve , determine the curve formula Y=m+nX (m, n are constants), as shown in Figure 1.

The marking process is selected according to the stress, and should meet various conditions of high and low stress. Generally, representative 0.1t, 0.5t, 1t, 2t, 5t, 10t, and 20t conditions are selected for verification.

Test the size of the coercivity under the respective stresses, G0.1, G0.5, G1, G2, G5, G10.

Draw a two-dimensional curve based on the above data, and the unit of abscissa is t, and the values are 0.1, 0.5, 1, 2, 5, and 10 respectively.

The unit of the ordinate is G, that is, the points are selected according to the size of the coercive force of the test. Draw correspondingly respectively, and finally use the least squares method to fit the curve according to the linear relationship of the curve.

It can be seen from Figure 1 that there is a certain linear curve relationship between the test signal and the calibration force value, so the wheel pressure of the crane can be prepared to be measured through the test signal.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (3)

1. A crane wheel pressure test method based on coercivity, characterized in that the steps are as follows: (1) Wind the excitation coil and detection coil on the U-shaped probe, place the U-shaped probe on the side of the track, excite the coil through AC excitation, and generate a magnetic field. Under the action of the exciting magnetic field, the track generates a hysteresis loop and detects The coil uses a sinusoidal signal to detect the hysteresis loop to obtain the completed hysteresis loop; (2) The detection system converts the detected magnetic field signal into an electrical signal through a digital-to-analog converter; (3) Calibrate the corresponding relationship between the pressure and the measured electrical signal through the test, and use a linear curve to describe the corresponding relationship; (4) Carry out test calibration on the force-signal curve of the entire test system, the calibration is as follows: according to a given force value, measure the magnitude of the magnetic field signal generated by it, measure multiple sets of data, and judge its linear relationship. 2 . The coercivity-based crane wheel pressure test method according to claim 1 , wherein in the step (1), the excitation coil generates a working magnetic field by applying an alternating current. 3 . 3. The crane wheel pressure test method based on coercive force according to claim 1, characterized in that, in the step (4), the given force value is determined by a material testing machine or a force device.