CN103017954B - Measuring method for plate stress field - Google Patents

Abstract

The invention relates to a method for measuring a flat plate stress field. In this method, sensor probes are arranged in a square in the area to be tested for plate stress to form an array, and under the action of the internal program of the industrial computer, the value and direction of the plate stress on each array line are measured in time through the multiplex switch and the pulse transceiver card, and finally Each set of measurement data is synthesized by orthogonal decomposition to form the distribution of the magnitude and direction of the stress field in the area to be measured. Compared with the traditional flat plate stress measurement method, the invention improves the measurement efficiency, simplifies the operation, can give the distribution of the stress field in a specified area, and has wide applicability.

Description

A Method for Measuring the Stress Field of a Flat Plate

1. Technical field

The invention relates to a method for measuring a flat plate stress field. This method has high measurement efficiency and can give the size, direction and distribution of the stress field in the area to be measured. It is easy to operate and is especially suitable for high-speed measurement and analysis of the stress field distribution of flat plates. It can be widely used in aviation, aerospace, weapons, automobiles, and other fields. Flat plate stress field measurement and analysis.

2. Background technology

The residual stress measurement methods mainly include mechanical method and physical method. Among them, the mechanical method will cause damage to the structure and is not suitable for stress detection of non-destructive structures; the physical method mainly includes X-ray diffraction method, magnetic method, neutron diffraction method and ultrasonic method, etc. Considering safety and portability, ultrasonic The method has obvious advantages in many non-destructive testing stress methods.

The traditional ultrasonic non-destructive testing stress method uses the method of one shot and one shot or one shot and two shots to detect the stress value and the state of tension and compression in the narrow area between the probes parallel to the direction of the sensor. The measurement efficiency is low and it is not suitable for large-scale Measurement cannot give the actual distribution state of the stress field in the area to be measured. The method of simply relying on the array sensor probe only changes one measurement into multiple measurements at the same time, and cannot give the actual situation of the stress area.

3. Contents of the invention

The purpose of the present invention is to provide a method for measuring the stress field of a flat plate. It involves square array sensor probes to measure the stress field of a flat plate, and the measurement data is depicted as a stress field grid. The stress value, direction, and tension and compression state of all focal points in the grid are synthesized by an orthogonal decomposition method to determine the actual stress field. The stress distribution situation solves the problem of analyzing the profitability of the stress field of the plate, and provides a new way of thinking for the measurement of the distribution law of the stress field of the plate.

The present invention is achieved like this:

A flat plate stress measurement method, using 32 ultrasonic transducers around the central magnetic base to form a square array of 8 probes on each side, and the probe wires on each side form a group of arrays. The probe wire harness is connected to a 16-way multiplex switch. The 16-way multiplexing switch is connected with the pulse transceiver card through the data line, and the pulse transceiver card is connected with the industrial computer control system through the data line.

After the test starts, the control system of the industrial computer sends out a signal, controls the pulse transceiver card to send and receive pulse data and controls one way of the multi-way switch to be connected, and the sensor collects the stress value information of one way and sends it back to the control system of the industrial computer. Stress value information corresponding to 8 horizontal lines and 8 vertical lines in the stress concentration area. The industrial computer system analyzes and calculates the stress state such as the stress distribution and direction of the plate stress area based on the collected 16 stress value information.

When a set of stress area tests is completed, the array can rotate the central magnetic base at any angle to measure positions in other directions. When the magnetic base is released, other areas can be replaced for testing, thereby completing the stress distribution of the stress field in a larger range in turn. test.

The stress equivalent orthogonal decomposition method proposed by the invention can well solve the problem of comprehensive analysis of 16 stress lines after testing, and has a good effect on transforming stress line measurement into surface measurement.

4. Description of drawings

Figure 1 Schematic diagram of plate stress measurement system

Figure 2 Schematic diagram of stress point selection

Fig.3 Schematic diagram of stress equivalent orthogonal decomposition

Reference numerals are explained as follows: array probe wire harness 1, data line 2, probe 3, 16-way multiplex switch 4, pulse transceiver card 5, magnetic base 6, base switch 7, industrial computer control system 8.

5. Specific implementation

The specific embodiment of the present invention is described in detail below:

As shown in Figure 1, after selecting the stress area to be measured, place the magnetic base 6 in it and tighten the switch from position 1 to position 2, and the magnetic base is tightly adsorbed on the plate. Eight probes 3 on each side in a square array around the magnetic base 6 constitute a stress array measurement matrix. The 8 probes 3 on each side of the square lead the wires into the array probe wire bundle 1, and the four array probe wire bundles 1 are connected to the 16-way multiplexer 4 in sequence, and the 16-way multiplexer 4 passes the data line 2 and the pulse The transceiver card 5 is connected, and the pulse transceiver card 5 is connected with the industrial computer control system 8 through the data line 2.

As shown in Figure 2, after the test starts, under the action of the industrial computer control system 8, the 16-way multi-way switch 4 turns on each group of measurement circuits in turn, and the probes facing the opposite side of the square sequentially collect the magnitude and direction of the internal line stress in the corresponding stress area. After the measurement of 16 pairs of sensor probes 3 is completed, the industrial computer control system 5 stores 16 sets of stress value and direction data, namely:

σ _L1|L19 , σ _L2|L18 ... σ _L10|L11 ; σ _R2|R12 , σ _R3|R13 ... σ _R10|R20 . The size and direction of these 16 groups of stress values are equivalent to the size and direction of the force, which can be decomposed orthogonally, for example: take the position A in Figure 2, the size and direction of the horizontal stress value are (tensile stress); the vertical direction The magnitude and direction of the stress value are (tensile stress). As shown in Figure 3, the magnitude and direction of the final stress at this point can be synthesized into a state of tensile stress with a direction oblique to 45°. In the same way, the stress value and stress direction of the intersection points of 81 stress lines in the square matrix can be calculated accordingly, and the distribution law of the plate stress field in this area can be analyzed accordingly. When the stress field test of the whole area is completed, loosen the magnetic base switch from position 2 to position 1, and turn the square matrix at a certain angle to measure the distribution of the stress field at the next angle position. After the analysis of the overall stress distribution in this area is completed, it can be moved to other locations for stress analysis.

The method has the advantages of simple measurement, large data capacity and high measurement efficiency, and can be widely used in the fields of plate stress measurement and analysis in aviation, spaceflight, navigation, weapons, automobiles and the like.

Claims (1)

1. a dull and stereotyped stress field method, it is characterized in that: get 32 ultrasonic transducer probes form 8, every limit probe square array around central magnetic base, the probe wire on every limit forms a group pattern probe wire bundle and accesses in No. 16 multicircuit switches, No. 16 multicircuit switches are connected with pulse card feeding-discharging by data line, pulse card feeding-discharging is connected with industrial computer control system by data line, multicircuit switch Time-sharing control every road, No. 16 break-makes, each circuit-switched data is gathered by pulse card feeding-discharging, industrial computer control system carries out data processing, after test starts, industrial computer control system sends signal, gating pulse card feeding-discharging transmission and reception pulse data and control multicircuit switch one tunnel connect, sensor gathers a road stress value information back industrial computer control system, circulation like this 16 times, namely region of stress concentration laterally 8 lines are obtained, longitudinally corresponding above 8 lines stress value information, industrial computer system calculates the state of this dull and stereotyped stress area stress according to the 16 road stress value information analyses gathered, when one group of stress area has been tested, this array can central magnetic base be that axle rotates and arbitrarily angledly carries out other direction position measurements, other regions can be changed test after unclamping magnetic bases, thus complete the test of wider dull and stereotyped stress field stress distribution successively.