Device and method for metering striking center distance of pendulum shaft of pendulum impact testing machine

Abstract

The invention discloses a device and method for metering the striking center distance of a pendulum shaft of a pendulum impact testing machine, and the device comprises a timing and counting device which is fixed at the top end of a tripod. The timing and counting device comprises a single chip microcomputer, a laser sensor and a display; the output end of the laser sensor is connected with the digital quantity input end of the single-chip microcomputer, and the single-chip microcomputer is connected with the display. The output end of the laser sensor transmits the variation of the swing times to the single chip microcomputer; the single chip microcomputer accumulates the received swing times of the pendulum bob, when the laser sensor receives the swing signal for the first time, the single chip microcomputer starts an internal timer, and when the swing times are 200 times, timing is stopped; reading a timing count value, and calculating a strike center distance according to national metrological verification regulations; the technical problem that the measurement accuracy is affected due to the fact that time errors are easily introduced due to asynchronous actions when the measurement of the distance from the axis of the pendulum shaft to the striking center is started and finished manually according to a stopwatch is solved.

Description

Technical Field

[0001] The invention belongs to the field of measurement technology, and in particular relates to a device and method for measuring the striking center distance of a pendulum shaft of a pendulum impact testing machine. Background Art

[0002] The pendulum impact test is a common material mechanics test method that evaluates the impact resistance of materials by impact loading them. The pendulum impact test is widely used in the field of material mechanics, especially in the research and development of engineering materials, metal materials, plastic materials, etc. This test method can evaluate key performance indicators of materials such as toughness, brittleness, and fracture capacity, which is of great significance for ensuring the safety and reliability of materials.

[0003] The striking center distance in the present invention refers to the distance from the pendulum shaft axis to the striking center of the pendulum impact testing machine.

[0004] The test scope of pendulum impact test includes but is not limited to the following aspects: (1) Material performance evaluation: Through impact testing, the response ability of materials under complex working conditions can be evaluated, such as impact resistance, failure form, etc. This has important reference value for selecting suitable materials and designing precise structures.

[0005] (2) Safety assessment: In some high-risk fields, such as aerospace and automotive, pendulum impact tests are widely used to evaluate the safety performance of materials in the event of accidents, providing important protection for product users.

[0006] (3) Standard test methods: There are corresponding standard test methods for pendulum impact tests in various industries, such as ASTM E23, ISO 179-1, GB / T 3039, etc. These standards ensure the repeatability and comparability of the tests, and are of great significance for data comparison and technical exchanges between different laboratories.

[0007] The national metrology verification regulations JJG145-2007 "Verification Regulations for Pendulum Impact Testing Machines" have the following requirements for the center distance of the testing machine: Distance from swing axis to striking center l 1 It should be consistent with the distance l from the pendulum axis to the center of the sample, and the value should be 0.995l-0.005l -0.995l+0.005l; Standard instruments include levels, calipers, optical inclinometers, and dial indicators or stopwatches.

[0008] According to the metrological characteristics requirements and the selected standard instrument, the metrological method given in the regulations has certain human errors. Usually, the time required for 100 swing cycles is about 173 seconds. Long-term counting is prone to over-counting or missing counts. Manually starting and ending with a stopwatch is also prone to introducing time errors due to asynchronous actions, which in turn affects the measurement accuracy. Summary of the invention

[0009] The technical problem to be solved by the present invention is: to provide a device and method for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine, so as to solve the technical problems that the measurement of the distance from the pendulum shaft axis to the strike center is easily introduced into the time error due to the manual start and end of the stopwatch, and the asynchronous action, thereby affecting the measurement accuracy.

[0010] The technical solution of the present invention is: A device for measuring the striking center distance of a pendulum shaft of a pendulum impact testing machine, the device comprising a timing and counting device, the timing and counting device being fixed on the top of a tripod; the timing and counting device comprising a single-chip microcomputer, a laser sensor and a display; the output end of the laser sensor is connected to the digital quantity input end of the single-chip microcomputer, the single-chip microcomputer is connected to the display; a timing counter is integrated in the single-chip microcomputer.

[0011] The timing and counting device also includes a power supply, which is respectively connected to the single-chip microcomputer, the laser sensor and the display.

[0012] The tripod is height adjustable.

[0013] The timing and counting device is fixed in the box body, and the box body is fixed on the top of the tripod; the laser sensor emits laser through a hole or a hole opened in the box body.

[0014] A method for using a device for measuring the striking center distance of a pendulum shaft of a pendulum impact testing machine, the method comprising: Step 1: Paste reflective paper on the pendulum; Step 2: Adjust the height of the tripod so that the light emitted by the laser sensor of the timing and counting device at the top of the tripod can illuminate the reflective paper when the pendulum swings; Step 3, the output end of the laser sensor transmits the change in the number of swings to the single-chip microcomputer; the single-chip microcomputer accumulates the number of swings of the pendulum received, and when the laser sensor receives the swing signal for the first time, the single-chip microcomputer starts the internal timer, and stops timing when the number of swings reaches 200 times; Step 4: Read the timing count value and calculate the striking center distance according to the national metrology verification regulations.

[0015] The reflective paper is rectangular and is pasted vertically on the pendulum.

[0016] Reset the data of the timing and counting device before use.

[0017] Beneficial effects of the present invention: The present invention calculates the striking center distance by automatically measuring the number and time of the pendulum swing, thereby avoiding human intervention and improving the accuracy of the strategy; it solves the technical problems that the measurement of the distance from the pendulum axis to the striking center is easily introduced due to the introduction of time error due to the manual start and end of the stopwatch, thereby affecting the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the device of the present invention; Figure 2 It is a schematic structural diagram of the timing and counting device of the present invention; Figure 3 This is the structural diagram of the pendulum impact test. DETAILED DESCRIPTION

[0019] A device and method for measuring the strike center distance of a pendulum impact tester, the device comprising a tripod and a timing and counting device, etc.; the timing and counting device comprises a single-chip microcomputer, a laser sensor and a display, and a timing counter is integrated in the single-chip microcomputer; the output end of the laser sensor is connected to the digital input end of the single-chip microcomputer. The single-chip microcomputer is connected to the display.

[0020] The box is used to install components. There are threaded holes at the bottom of the box, and the tripod is fixed on the box. The power input is 220V AC, and the output DC is used to power the microcontroller, laser sensor and display screen. The timing counter starts and stops through program control. The output end of the laser sensor transmits the change in the number of swings to the microcontroller through a signal. The microcontroller accumulates the number of swings of the pendulum received. When the laser sensor receives the swing signal for the first time, the microcontroller starts the internal timer. When the number of swings reaches 200, the timing is stopped, and the obtained time value is transmitted to the display screen through the data line.

[0021] After the laser emitted by the laser sensor hits the reflective paper, it is emitted back to the laser probe and recorded once. The reflective paper needs to be pasted on the appropriate position on the pendulum, and the reflective paper of appropriate length and size should be selected so that the laser sensor can receive a signal every time the pendulum swings.

[0022] There are many communication protocols for microcontrollers, such as SPI, I2C, etc. The communication protocol enables the microcontroller to receive signals at high speed and multiple signals at the same time. Considering the close distance between the components, SPI communication is a good choice, but the communication protocol is not limited to this one.

[0023] The display interface of the display screen includes two windows, "Swing Number" and "Measurement Time", and a record table. The record table records the measurement time and the measured values ​​of the swing number during the calibration process. The "Number Calibration" and "Time Calibration" functions are written in the program of the single-chip microcomputer. The counting function and timer of the calibration device are calibrated every year. If the error of the counting and time parameters exceeds the allowable error, they are calibrated and adjusted.

[0024] In the present invention, the laser sensor is mounted on a tripod, and the tripod is adjusted so that the emitted laser is vertically irradiated on the reflective paper on the pendulum, and the tripod is ensured to be stable.

[0025] Turn on the power of the device, swing the pendulum to ensure that the counting signal reception and timing function are normal, and set the timing count to zero. The installation regulations require that the pendulum be placed at an angle of no more than 5° and released freely. Observe the timing count until the timing stops (swinging 100 cycles), read the time recorded on the display, and record it in the original calibration record. Calculate the impact center distance according to the formula required by the national metrology verification regulations JJG145-2007 "Verification Regulations for Pendulum Impact Testing Machines" l 1.

Claims

1. A device for measuring the center distance of the swing shaft of a pendulum impact testing machine, characterized in that: The device comprises a timing and counting device, which is fixed on the top of a tripod; the timing and counting device comprises a single-chip microcomputer, a laser sensor and a display; the output end of the laser sensor is connected to the digital quantity input end of the single-chip microcomputer, and the single-chip microcomputer is connected to the display; a timing counter is integrated in the single-chip microcomputer.

2. The device for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine according to claim 1, characterized in that: The timing and counting device also includes a power supply, which is respectively connected to the single-chip microcomputer, the laser sensor and the display.

3. The device for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine according to claim 1, characterized in that: The tripod is height adjustable.

4. The device for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine according to claim 1, characterized in that: The timing and counting device is fixed in the box body, and the box body is fixed on the top of the tripod; the laser sensor emits laser through a hole or a hole opened in the box body.

5. The method for using the device for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine according to claim 1, characterized in that: The method comprises: Step 1: Paste reflective paper on the pendulum; Step 2: Adjust the height of the tripod so that the light emitted by the laser sensor of the timing and counting device at the top of the tripod can illuminate the reflective paper when the pendulum swings; Step 3, the output end of the laser sensor transmits the change in the number of swings to the single-chip microcomputer; the single-chip microcomputer accumulates the number of swings of the pendulum received, and when the laser sensor receives the swing signal for the first time, the single-chip microcomputer starts the internal timer, and stops timing when the number of swings reaches 200 times; Step 4: Read the timing count value and calculate the striking center distance according to the national metrology verification regulations.

6. The method for using the device for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine according to claim 5, characterized in that: The reflective paper is rectangular and is pasted vertically on the pendulum.

7. The method for using the device for measuring the strike center distance of the pendulum shaft of a pendulum impact testing machine according to claim 5, characterized in that: Reset the data of the timing and counting device before use.

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