Resonance torsion pendulum test bench and test method for elastic specimens

Abstract

The present invention provides a resonant torsion pendulum test bench and test method for elastic specimens. The resonant frequency of the torsion pendulum mechanism is changed by adjusting the weight and the swing radius of the counterweight block. The motor is started to drive the torsion pendulum mechanism. In each torsion pendulum cycle, the closed-loop control system controls the motor to load in the forward direction following the torsion pendulum direction in real time, generates excitation and continuously strengthens it, so that the reciprocating torsion pendulum torque and angle of the elastic specimen gradually increase until the maximum torsion pendulum torque reaches the maximum torque required by the test. The reciprocating torsion pendulum state is maintained and a fatigue torsion pendulum test is entered. The control system monitors the torsion pendulum angle at each maximum torsion pendulum torque. When the angle suddenly increases and changes suddenly, it can be determined that the elastic specimen has been damaged or failed. The present invention utilizes the principle of resonance and only requires a relatively small power motor to drive it. It is suitable for fatigue torsion pendulum tests of various elastic specimens and has the characteristics of simple structure, small size, energy saving, no noise, no pollution, and high frequency.

Description

Technical Field

[0001] The invention relates to a resonant torsion pendulum test bench for elastic specimens and a test method. The test bench utilizes the principle of resonance and can be driven by a relatively small-power motor. It has the characteristics of simple structure, small size, energy saving, no noise, no pollution and high frequency, and is particularly suitable for fatigue torsion pendulum tests of various elastic specimens. Background Art

[0002] At present, the elastic specimen torsion pendulum test benches used at home and abroad are mainly driven by servo hydraulic swing cylinders or motors directly, without inertial swing rods and counterweights that can generate resonance. Due to the hydraulic return resistance and speed limitations, the servo hydraulic swing cylinder has problems such as low torsion frequency, high energy consumption, large test bench size, and high noise and pollution. Since the test bench directly driven by the motor has no resonance mechanism, it needs to be equipped with a very high-power motor, which consumes a lot of energy and the size of the entire test bench is also large. Summary of the invention

[0003] The present invention provides a resonant torsion pendulum test bench and test method for elastic specimens. The resonant frequency of the torsion pendulum mechanism is changed by adjusting the weight and the swing radius of the counterweight block. The motor is started to drive the torsion pendulum mechanism. In each torsion pendulum cycle, the closed-loop control system controls the motor to load in the forward direction following the torsion pendulum direction in real time, generates excitation and continuously strengthens it, so that the reciprocating torsion pendulum torque and angle of the elastic specimen gradually increase until the maximum torsion pendulum torque reaches the maximum torque required by the test. The reciprocating torsion pendulum state is maintained and a fatigue torsion pendulum test is entered. The control system monitors the torsion pendulum angle at each maximum torsion pendulum torque. When the angle suddenly increases and changes suddenly, it can be determined that the elastic specimen has been damaged or failed. The present invention utilizes the principle of resonance and only requires a relatively small power motor to drive it. It is suitable for fatigue torsion pendulum tests of various elastic specimens and has the characteristics of simple structure, small size, energy saving, no noise, no pollution, and high frequency.

[0004] The elastic specimen resonant torsion pendulum test bench of the present invention mainly comprises a flat plate, an inertial shaft mounting seat, a motor seat, a motor (variable frequency or servo motor), an encoder, a coupling, an inertial swing shaft, a bearing seat, a bearing, an inertial swing rod, a counterweight, a torsion end flange, an elastic specimen, a test end flange, a torque sensor, and a sensor mounting seat; the flat plate is a thick steel plate with a T-slot thereon, the inertial shaft mounting seat is fixed on the flat plate by T-bolts, the motor seat is mounted on one side of the inertial shaft mounting seat, the motor is fixed on the motor seat, and the encoder is mounted on the rear end of the motor; the coupling is respectively mounted on the motor output shaft and the input shaft of the inertial swing shaft and fixed with a flat key, and the shaft shoulders on both sides of the inertial swing shaft are respectively installed The outer ring of the bearing is installed in the inner hole of the bearing, and the outer ring of the bearing is installed in the bearing seat. The two bearing seats are respectively installed in the assembly holes on both sides of the inertia shaft mounting seat; the inertia swing arm is sleeved on the intermediate shaft of the inertia swing shaft and fixed with a flat key, and the counterweight blocks are installed on both sides of the inertia swing arm; the output shaft of the inertia swing shaft is installed in the inner hole on one side of the torsion end flange and fixed with a flat key, the flange on one side of the elastic specimen is connected and fixed with the flange on the other side of the torsion end flange, and the flange on the other side of the elastic specimen is connected and fixed with the flange on the test end; the torque sensor is connected to the other side of the test end flange through the flange, and the flange on the other side of the torque sensor is fixed on the sensor mounting seat, and the sensor mounting seat is fixed on the flat plate through T-bolts.

[0005] The torsion pendulum mechanism of the test bench is mainly composed of a motor, a coupling, an inertial swing shaft, an inertial swing rod, a counterweight, a torsion end flange, an elastic specimen, a test end flange, and a torque sensor. The resonance period formula of the torsion pendulum mechanism is:

[0006]

[0007] T-resonance period

[0008] M - moment of inertia

[0009] K-torsional stiffness of elastic specimen

[0010] Torsional stiffness is a constant determined by the material and size of the elastic specimen. The moment of inertia is mainly determined by the weight of the inertial pendulum and the counterweight mounted on it, as well as the inertial swing radius. The resonant period can be changed by adjusting the weight of the counterweight and the swing radius. The reciprocal of the resonant period is the resonant frequency of the torsion pendulum mechanism.

[0011] The reciprocating torsion angle and speed of the elastic specimen are detected in real time by an encoder, and the reciprocating torsion torque of the elastic specimen is detected in real time by a torque sensor.

[0012] The method and steps of the resonant torsion pendulum test of elastic specimens are as follows:

[0013] ① Before the test, the elastic specimen is fixed on the test bench, and the counterweights are installed on both sides of the inertial pendulum. The motor is started to generate a torque in one direction (usually the maximum torque of the motor is used), and then the motor torque is quickly released to let the motor be in a free state. At this time, the entire torsion pendulum mechanism will produce a reciprocating torsion pendulum with a very small amplitude. The control system can obtain the frequency of the reciprocating torsion pendulum by monitoring the angle and speed signals of the encoder. This frequency is the resonant frequency of the torsion pendulum mechanism.

[0014] ② Repeatedly adjust the weight and swing radius of the counterweight block to change the resonant frequency of the torsion pendulum mechanism until the resonant frequency of the torsion pendulum mechanism is adjusted to the torsion pendulum frequency required by the elastic specimen test;

[0015] ③ Start the motor to drive the torsion pendulum mechanism. In each torsion pendulum cycle, the closed-loop control system controls the motor to load in the forward direction of the torsion pendulum in real time, generating excitation and continuously strengthening it (similar to the principle of swinging on a swing). The amplitude of the torsion pendulum becomes larger and larger, so that the reciprocating torsion pendulum torque and angle of the elastic specimen gradually increase until the maximum torsion pendulum torque reaches the maximum torque required by the test; in order to maintain the maximum torque amplitude, the control system automatically adjusts the loading torque and duration of the motor during each reciprocating torsion pendulum, so that the elastic specimen is officially in the fatigue torsion pendulum test stage required by the test;

[0016] ④ After the elastic specimen enters the fatigue pendulum test stage, the control system monitors the pendulum angle at each maximum pendulum torque. For a normal elastic specimen, at the maximum torque, the maximum pendulum angle usually remains basically unchanged; when the angle suddenly increases and changes suddenly, it can be determined that the elastic specimen has been damaged or failed, and the control system automatically stops the test and checks the elastic specimen;

[0017] ⑤ Due to the different shapes, sizes, and connection methods of the elastic specimens, when performing resonant torsion pendulum tests on different elastic specimens, it is necessary to replace the matching torsion end flange and test end flange to meet the connection and fixation requirements of various elastic specimens;

[0018] ⑥ According to the different test requirements of the elastic specimen, by installing the counterweight on both sides or one side of the inertial pendulum, a symmetrical resonant torsion pendulum test or an asymmetrical resonant torsion pendulum test can be carried out respectively.

[0019] The present invention provides a resonant torsion pendulum test bench and a test method for elastic specimens. The test bench utilizes the principle of resonance and can be driven by a relatively small-power motor. It has the characteristics of simple structure, small size, energy saving, no noise, no pollution, and high frequency. It is particularly suitable for fatigue torsion pendulum tests of various elastic specimens and has good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a three-dimensional effect diagram when the counterweight blocks of the elastic specimen resonant torsion pendulum test bench of the present invention are installed on both sides of the inertial pendulum rod.

[0021] Figure 2 It is a three-dimensional effect diagram when the counterweight block of the elastic specimen resonant torsion pendulum test bench of the present invention is installed on one side of the inertial pendulum rod.

[0022] Figure 3 It is a partial three-dimensional cross-sectional view of the portion from the motor to the inertial swing axis of the elastic specimen resonant torsion pendulum test bench of the present invention.

[0023] 1-plate, 2-inertia shaft mounting seat, 3-counterweight, 4-motor, 5-inertia swing rod, 6-bearing seat, 7-elastic specimen, 8-sensor mounting seat, 9-encoder, 10-motor seat, 11-test end flange, 12-torque sensor, 13-coupling, 14-bearing, 15-torsion end flange, 16-inertia swing shaft DETAILED DESCRIPTION

[0024] The elastic specimen resonant torsion pendulum test bench of the present invention mainly comprises a plate 1, an inertial shaft mounting seat 2, a motor seat 10, a motor 4 (variable frequency or servo motor), an encoder 9, a coupling 13, an inertial swing shaft 16, a bearing seat 6, a bearing 14, an inertial swing rod 5, a counterweight 3, a torsion end flange 15, an elastic specimen 7, a test end flange 11, a torque sensor 12, and a sensor mounting seat 8; the plate 1 is a thick steel plate with a T-slot thereon, the inertial shaft mounting seat 2 is fixed to the plate 1 by T-bolts, the motor seat 10 is mounted on one side of the inertial shaft mounting seat 2, the motor 4 is fixed on the motor seat 10, and the encoder 9 is mounted on the rear end of the motor 4; the coupling 13 is respectively mounted on the output shaft of the motor 4 and the input shaft of the inertial swing shaft 16, and is fixed with a flat key, and the shafts on both sides of the inertial swing shaft 16 The shoulders are respectively installed in the inner holes of the bearings 14, the outer rings of the bearings 14 are installed in the bearing seats 6, and the two bearing seats 6 are respectively installed in the assembly holes on both sides of the inertia shaft mounting seat 2; the inertia swing rod 5 is sleeved on the intermediate shaft of the inertia swing shaft 16 and fixed with a flat key, and the counterweights 3 are installed on both sides of the inertia swing rod 5; the output shaft of the inertia swing shaft 16 is installed in the inner hole on one side of the torsion end flange 15 and fixed with a flat key, the flange on one side of the elastic specimen 7 is connected and fixed with the flange on the other side of the torsion end flange 15, and the flange on the other side of the elastic specimen 7 is connected and fixed with the test end flange 11; the torque sensor 12 is connected to the other side of the test end flange 11 through a flange, and the other side of the torque sensor 12 is fixed to the sensor mounting seat 8, and the sensor mounting seat 8 is fixed to the flat plate 1 through T-bolts.

[0025] The torsion pendulum mechanism of the test bench is mainly composed of a motor 4, a coupling 13, an inertial swing shaft 16, an inertial swing rod 5, a counterweight 3, a torsion end flange 15, an elastic specimen 7, a test end flange 15, and a torque sensor 12. The resonance period formula of the torsion pendulum mechanism is:

[0026]

[0027] T-resonance period

[0028] M - moment of inertia

[0029] K-torsional stiffness of elastic specimen

[0030] Torsional stiffness is a constant determined by the material and size of the elastic specimen 7. The moment of inertia is mainly determined by the weight of the inertial pendulum 5 and the counterweight 3 mounted thereon, as well as the inertial swing radius. By adjusting the weight and swing radius of the counterweight 3, the resonance period can be changed. The inverse of the resonance period is the resonance frequency of the torsion pendulum mechanism.

[0031] The reciprocating torsion angle and speed of the elastic test piece 7 are detected in real time by the encoder 9 , and the reciprocating torsion torque of the elastic test piece 7 is detected in real time by the torque sensor 12 .

[0032] The method and steps of the resonant torsion pendulum test of elastic specimen 7 are as follows:

[0033] 1-plate, 2-inertia shaft mounting seat, 3-counterweight, 4-motor, 5-inertia swing rod, 6-bearing seat, 7-elastic specimen, 8-sensor mounting seat, 9-encoder, 10-motor seat, 11-test end flange, 12-torque sensor, 13-coupling, 14-bearing, 15-torsion end flange, 16-inertia swing shaft

[0034] ① Before the test, the elastic test piece 7 is fixed on the test bench, the counterweight 3 is installed on both sides of the inertial pendulum 5, the motor 4 is started to generate a torque in one direction in the form of torque (usually the maximum torque of the motor 4 is used), and then the torque of the motor 4 is quickly released to make the motor 4 in a free state. At this time, the entire oscillating mechanism will produce a reciprocating oscillation with a very small amplitude. The control system can obtain the frequency of the reciprocating oscillation by monitoring the angle and speed signals of the encoder 9, and this frequency is the resonant frequency of the oscillating mechanism;

[0035] ② Repeatedly adjust the weight and the swing radius of the counterweight 3 to change the resonant frequency of the oscillating mechanism until the resonant frequency of the oscillating mechanism is adjusted to the oscillating frequency required by the test of the elastic specimen 7;

[0036] ③ Start the motor 4 to drive the torsion pendulum mechanism. In each torsion pendulum cycle, the closed-loop control system controls the motor 4 to load in the forward direction of the torsion pendulum in real time, generates excitation and continuously strengthens it (similar to the principle of swinging on a swing), and the amplitude of the torsion pendulum becomes larger and larger, so that the reciprocating torsion pendulum torque and angle of the elastic specimen 7 gradually increase until the maximum torsion pendulum torque reaches the maximum torque required by the test; in order to maintain the maximum torque amplitude, the control system automatically adjusts the loading torque and duration of the motor 4 during each reciprocating torsion pendulum, so that the elastic specimen 7 is officially in the fatigue torsion pendulum test stage required by the test;

[0037] ④ After the elastic specimen 7 enters the fatigue pendulum test stage, the control system monitors the pendulum angle at each maximum pendulum torque. For a normal elastic specimen 7, at the maximum torque, the maximum pendulum angle usually remains basically unchanged; when the angle suddenly increases and changes suddenly, it can be determined that the elastic specimen 7 is damaged or failed, and the control system automatically stops the test and checks the elastic specimen 7:

[0038] ⑤ Since the shapes, sizes, and connection methods of the two sides of the elastic test piece 7 are different, when performing the resonant torsion pendulum test of different elastic test pieces 7, it is necessary to replace the torsion end flange 15 and the test end flange 11 that match them to meet the connection and fixing requirements of various elastic test pieces 7;

[0039] ⑥ According to different test requirements of the elastic specimen 7, by installing the counterweight 3 on both sides or one side of the inertial pendulum 5, a symmetrical resonant torsion pendulum test or an asymmetrical resonant torsion pendulum test can be carried out respectively.

Claims

1. The elastic specimen resonant torsion pendulum test bench is mainly composed of a plate, an inertial shaft mounting seat, a motor seat, a motor, an encoder, a coupling, an inertial swing shaft, a bearing seat, a bearing, an inertial swing rod, a counterweight, a torsion end flange, an elastic specimen, a test end flange, a torque sensor, and a sensor mounting seat; its characteristics are: The flat plate is a thick steel plate with a T-slot on it. The inertia shaft mounting seat is fixed on the flat plate by T-bolts. The motor seat is installed on one side of the inertia shaft mounting seat, the motor is fixed on the motor seat, and the encoder is installed on the rear end of the motor; the coupling is respectively mounted on the motor output shaft and the input shaft of the inertia swing shaft and fixed with a flat key, the shoulders on both sides of the inertia swing shaft are respectively installed in the inner holes of the bearings, the outer rings of the bearings are installed in the bearing seats, and the two bearing seats are respectively installed in the assembly holes on both sides of the inertia shaft mounting seat; the inertia swing arm is mounted on the intermediate shaft of the inertia swing shaft and fixed with a flat key, and the counterweights are installed on both sides of the inertia swing arm; The output shaft of the shaft is installed in the inner hole on one side of the torsion end flange and fixed with a flat key, the flange on one side of the elastic specimen is connected and fixed to the flange on the other side of the torsion end flange, and the flange on the other side of the elastic specimen is connected and fixed to the test end flange; the torque sensor is connected to the other side of the test end flange through a flange, and the flange on the other side of the torque sensor is fixed to the sensor mounting seat, and the sensor mounting seat is fixed to the flat plate through T-bolts; the torsion pendulum mechanism of the test bench is mainly composed of a motor, a coupling, an inertial swing shaft, an inertial swing rod, a counterweight, a torsion end flange, an elastic specimen, a test end flange, and a torque sensor.

2. The resonant pendulum test bench of elastic specimen according to claim 1, wherein the test method is characterized in that: before the test, the elastic specimen is mounted and fixed on the test bench, the counterweight is mounted on both sides of the inertial pendulum, the motor is started to generate a torque in one direction in the form of torque, and then the motor torque is quickly released to allow the motor to be in a free state. At this time, the entire pendulum mechanism will generate a reciprocating pendulum with a very small amplitude. The control system can obtain the frequency of the reciprocating pendulum by monitoring the angle and speed signals of the encoder, and the frequency is the resonant frequency of the pendulum mechanism; the weight of the counterweight and the swing radius are repeatedly adjusted to change the resonant frequency of the pendulum mechanism until the resonant frequency of the pendulum mechanism is adjusted to the pendulum frequency required by the elastic specimen test; the motor is started to drive the pendulum mechanism, and in each pendulum cycle, the closed-loop control system controls the motor to follow the pendulum direction in real time to load in the forward direction, generate excitation and continuously enhance it, and the amplitude of the pendulum becomes larger and larger, so that the reciprocating pendulum torque and angle of the elastic specimen gradually increase until the maximum pendulum torque reaches the test value. the maximum torque required by the test; in order to maintain the maximum torque amplitude, the control system automatically adjusts the loading torque and duration of the motor during each reciprocating torsion swing, so that the elastic specimen is officially in the fatigue torsion swing test stage required by the test; after the elastic specimen enters the fatigue torsion swing test stage, the control system monitors the torsion swing angle at each maximum torsion swing torque. For normal elastic specimens, at the maximum torque, the maximum torsion swing angle is usually basically unchanged; when the angle suddenly increases and changes suddenly, it can be determined that the elastic specimen has been damaged or failed, and the control system automatically stops the test and checks the elastic specimen; due to the different shapes, sizes, and connection methods on both sides of the elastic specimen, when performing resonant torsion swing tests on different elastic specimens, it is necessary to replace the matching torsion end flange and test end flange to meet the connection and fixation requirements of various elastic specimens; according to the different test requirements of the elastic specimen, by installing the counterweight on both sides or one side of the inertial pendulum, a symmetrical resonant torsion swing test or an asymmetric resonant torsion swing test can be performed respectively.

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