An automatic excitation system and method for indoor compaction specimen shear wave velocity test

Abstract

The present invention discloses an automatic excitation system and method for indoor compaction specimen shear wave velocity test, which has higher test accuracy and efficiency. It includes a test bracket, the test bracket has a trigger mounting end, a receiving mounting end, and a specimen mounting portion located between the trigger mounting end and the receiving mounting end, the specimen mounting portion is mounted with a specimen through a damping pad, the trigger mounting end is mounted with a trigger detector through a damping pad, the trigger detector is located directly below the specimen trigger end, the receiving mounting end is mounted with a receiving detector through a damping pad, the receiving detector cooperates with the end of the specimen trigger end, an excitation pad is provided between the trigger detector and the specimen, the excitation pad is U-shaped, and its two ends cooperate with the trigger detector and the specimen trigger end respectively; it also includes an excitation mechanism, the excitation mechanism is used to knock the middle of the excitation pad so that the wave reaches the specimen and the trigger detector at the same time.

Description

Technical Field

[0001] The invention relates to the technical field, and in particular to an automatic excitation system and method for indoor shear wave velocity testing of compaction specimens. Background Art

[0002] In the prior art indoor shear wave velocity test method for compacted specimens (publication number: CN102608211), a pad is placed between the trigger detector and the specimen, and the pad is manually struck to excite the detector and the specimen at the same time. This excitation method has the following disadvantages:

[0003] The exciting force is generated by manual tapping, and the magnitude and direction cannot be accurately controlled, especially since the tapping force is different for each test;

[0004] When testing again, the device needs to be reconnected after the pad is moved, resulting in low test accuracy and efficiency. Therefore, from the perspective of improving test accuracy and efficiency, an automatic excitation system and method is proposed based on the original indoor specimen shear wave velocity test method. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide an automatic excitation system and method for indoor compaction specimen shear wave velocity testing, which has higher test accuracy and efficiency.

[0006] The object of the present invention is achieved in that:

[0007] An automatic excitation system for shear wave velocity testing of compacted specimens indoors, comprising a test bracket, the test bracket having a trigger mounting end, a receiving mounting end, and a specimen mounting portion located between the trigger mounting end and the receiving mounting end, the specimen mounting portion being mounted with a specimen via a damping pad, the trigger mounting end being mounted with a trigger detector via a damping pad, the trigger detector being located directly below the trigger end of the specimen, the receiving mounting end being mounted with a receiving detector via a damping pad, the receiving detector being matched with the end of the trigger end of the specimen, an excitation pad being arranged between the trigger detector and the specimen, the excitation pad being U-shaped, and its two ends being matched with the trigger detector and the trigger end of the specimen respectively;

[0008] It also includes a vibration excitation mechanism, which is used to strike the middle part of the vibration excitation pad so that the wave reaches the test piece and triggers the detector at the same time.

[0009] Preferably, the damping pad with the trigger detector installed at the trigger mounting end of the test bracket is L-shaped, so that the damping pad has a high mounting surface and a low mounting surface, the trigger detector is installed on the low mounting surface, and the excitation pad is installed on the high mounting surface.

[0010] Preferably, a detector fixture is fixed to the receiving mounting end, and the upper and lower parts of the receiving detector are respectively mounted on the detector fixture via damping pads.

[0011] Preferably, it also includes a test computer and an engineering dynamic measuring instrument. The trigger detector and the receiving detector are respectively connected to the engineering dynamic measuring instrument. The engineering dynamic measuring instrument is used to collect data from the trigger detector and the receiving detector. The engineering dynamic measuring instrument is connected to the test computer. The test computer performs data calculation, analysis and processing based on the data received by the engineering dynamic measuring instrument.

[0012] Preferably, the excitation mechanism includes an exciter bracket and a spring sheet and a wheel disc installed on the exciter bracket, the spring sheet is upright just above the wheel disc, a striking hammer is flatly arranged on the spring sheet, a reset spring is arranged between the spring sheet and the exciter bracket, the reset spring is arranged facing away from the striking hammer, the wheel disc is driven to rotate by a driving mechanism, a lever is provided on the wheel disc, the lever is located at the lower end of the spring sheet, so that the reset spring is compressed and the spring sheet is deformed, the lever can slide over the spring sheet and continue to rotate with the wheel disc, thereby causing the striking hammer to strike the middle part of the excitation pad, and after the striking is completed, the striking hammer returns to its original position under the action of the reset spring and the spring sheet.

[0013] Preferably, the driving mechanism comprises a DC power supply, a DC speed regulator, and a DC motor which are electrically connected in sequence, and the rotating shaft of the DC motor is dynamically connected to the core shaft of the wheel disc through a transmission shaft.

[0014] Preferably, an anti-slip pad is provided under the test bracket.

[0015] An automatic vibration excitation method for indoor compaction specimen shear wave velocity testing includes an automatic vibration excitation system. The automatic vibration excitation method is:

[0016] The wheel rotates, driving the lever to rotate;

[0017] When the lever rotates to contact the lower end of the spring sheet, the lever continues to rotate and presses down the lower end of the spring sheet, causing the spring sheet to deform under pressure, and at the same time the return spring enters a compressed state, accumulating elastic potential energy;

[0018] When the lever slides over the lower end of the spring sheet, the reset spring and the spring sheet release elastic potential energy, and the hammer pops out toward the test piece, striking the middle of the exciting pad to generate an exciting vibration, and then the reset spring and the spring sheet return to their original positions, and the wheel continues to rotate, entering the next exciting cycle;

[0019] The excited vibration pad transmits the vibration to the test piece and triggers the detector at the same time, and the test piece and the trigger detector receive the vibration signal at the same time;

[0020] The trigger detector that receives the fluctuation signal transmits the fluctuation signal to the engineering dynamic measuring instrument, and then transmits it to the test computer. The test piece that receives the fluctuation signal will eventually transmit the fluctuation signal to the receiving detector after the fluctuation propagates inside it. The receiving detector that receives the fluctuation signal transmits the fluctuation signal to the engineering dynamic measuring instrument, and then transmits it to the test computer. The test computer performs data calculation, analysis and processing based on the received data.

[0021] Preferably, the single vibration excitation method is: manually driving the lever to rotate, and releasing the lever after the lever slides over the lower end of the spring sheet, thereby generating a single vibration.

[0022] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0023] Adding specialized vibration equipment can standardize the vibration intensity, improve the accuracy and efficiency of the test, and at the same time meet the need for continuous vibration testing, which has great engineering practical value for improving the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention;

[0025] Figure 2 It is a structural schematic diagram of the excitation mechanism;

[0026] Figure 3 This is a schematic diagram of the improvement of the vibration pad;

[0027] Figure 4 is a schematic diagram of the structure of the driving mechanism;

[0028] Figure 5 Schematic diagram of the working process of the vibration pad. DETAILED DESCRIPTION

[0029] See also Figure 1-Figure 4 An automatic vibration excitation system for indoor shear wave velocity testing of compacted specimens includes a test bracket 19, wherein the test bracket 19 has a trigger mounting end, a receiving mounting end, and a specimen mounting portion located between the trigger mounting end and the receiving mounting end, wherein the specimen mounting portion is mounted with a specimen 14 via a damping pad, wherein a trigger detector 12 is mounted on the trigger mounting end via a damping pad, wherein the trigger detector 12 is located directly below the trigger end of the specimen 14, wherein a receiving detector 16 is mounted on the receiving mounting end via a damping pad, wherein the receiving detector 16 cooperates with the trigger end of the specimen 14, wherein an excitation pad 10 is arranged between the trigger detector 12 and the specimen 14, wherein the excitation pad 10 is U-shaped, wherein both ends thereof cooperate with the trigger detector 12 and the trigger end of the specimen 14 respectively; and an anti-slip pad is arranged under the test bracket 19.

[0030] The trigger mounting end of the test bracket 19 is equipped with a damping pad of the trigger detector 12 in an L shape, so that the damping pad has a high mounting surface and a low mounting surface. The trigger detector 12 is mounted on the low mounting surface, and the excitation pad 10 is mounted on the high mounting surface. The receiving mounting end is fixed with a detector fixture 15, and the upper and lower parts of the receiving detector 16 are respectively mounted on the detector fixture 15 through damping pads. The damping pad below the trigger detector 12 is also mounted on the trigger mounting end of the test bracket 19 through a fixture.

[0031] It also includes a test computer 21 and an engineering dynamic measuring instrument 22. The trigger detector 12 and the receiving detector 16 are respectively connected to the engineering dynamic measuring instrument 22. The engineering dynamic measuring instrument 22 is used to collect data from the trigger detector 12 and the receiving detector 16. The engineering dynamic measuring instrument 22 is connected to the test computer 21. The test computer 21 performs data calculation, analysis and processing based on the data received by the engineering dynamic measuring instrument 22.

[0032] It also includes an excitation mechanism, which is used to knock the middle of the excitation pad 10, so that the wave reaches the test piece at the same time and triggers the detector 1. The excitation mechanism includes an exciter bracket 6 and a spring sheet 7 and a wheel 5 installed on the exciter bracket 6. The spring sheet 7 is vertically arranged directly above the wheel 5. A knocking hammer 9 is arranged flat on the spring sheet 7. A reset spring 8 is arranged between the spring sheet 7 and the exciter bracket 6. The reset spring 8 is arranged opposite to the knocking hammer 9. The wheel 5 is driven to rotate by a driving mechanism. The wheel 5 has a lever, which is used to move the lower end of the spring sheet 7 to compress the reset spring 8 and deform the spring sheet 7. The lever can slide over the spring sheet 7 and continue to rotate with the wheel 5, thereby causing the knocking hammer 9 to knock the middle of the excitation pad 10. After the knocking is completed, the knocking hammer 9 returns to its original position under the action of the reset spring 8 and the spring sheet 7. The spring sheet 7 can be automatically reset by the reset spring 8, and there is no need to reconnect the device for multiple tests.

[0033] The driving mechanism comprises a DC power supply 1, a DC speed regulator 2, and a DC motor 3 which are electrically connected in sequence. The rotating shaft of the DC motor 3 is dynamically connected to the core shaft of the wheel disc 5 through a transmission shaft 4.

[0034] DC power supply 1 uses a switching power supply or a 18650 battery pack (3.7V*4), outputting 12V, 10A;

[0035] The DC speed regulator 2: adopts a simple PWM DC speed regulator, with a voltage of 12V and a frequency modulation range of 0-100%;

[0036] The DC motor 3: 12V, 1-180rpm, effective load 5kg.

[0037] The DC motor 3 needs to be fixed at an appropriate position and height, and the rotating plane of its rotor is parallel to the wheel disc 5. The transmission shaft is a straight metal rod, perpendicular to the above two planes and connecting the two. It can also be connected by a coupling or a gearbox. Working method of the power part: the power supply provides 12V DC. The speed regulator adjusts the output ratio by stepless speed change from 1 to 100%, corresponding to different motor speeds of 1 to 180rpm. Use it after adjustment and correction according to the test requirements. The torque of the DC motor is transmitted to the wheel disc through the transmission shaft.

[0038] The test bracket 19 is a metal frame, and the height and other dimensions are set according to the equipment requirements. Its function is to support the weight of the system equipment. The wheel 5 is made of aluminum alloy. The upper end of the steel spring sheet is fixed to the bracket, and the middle is connected to the reset spring by bolts. The other side of the reset spring is connected to the percussion hammer, and the lower end is a free end with rounded corners. The manufacturing size of the entire system is set according to the size of the test experimental device, and the percussion center should be at the center of the excitation pad.

[0039] An automatic excitation method for shear wave velocity testing of compacted specimens indoors:

[0040] Test Press Figure 1 Arrange the equipment and test specimens as shown. The test specimen preparation can refer to the existing technology. Pay attention to the spacing of the equipment, especially the distance between the percussion hammer and the exciting pad, to ensure that the percussion hammer will not hit the pad in a short free swing state. The large damping pads of the test should also be reasonably arranged and fixed.

[0041] The wheel 5 rotates, driving the lever to rotate;

[0042] When the lever rotates to contact the lower end of the spring sheet 7, the lever continues to rotate and presses down the lower end of the spring sheet, causing the spring sheet to deform under pressure, and at the same time the return spring enters a compressed state, accumulating elastic potential energy;

[0043] When the lever slides over the lower end of the spring sheet, the reset spring 8 and the spring sheet 7 release their elastic potential energy, and the hammer pops out toward the test piece, striking the middle of the exciting pad 10, generating an exciting vibration, and then the reset spring 8 and the spring sheet 7 return to their original positions, and the wheel continues to rotate, entering the next exciting cycle; the whole movement process is as follows: Figure 5 The AE process is shown in the figure.

[0044] The excited vibration pad 10 transmits the vibration to the test piece and the trigger detector 12 at the same time, and the test piece and the trigger detector 12 receive the vibration signal at the same time;

[0045] The trigger detector 12 that receives the fluctuation signal transmits the fluctuation signal to the engineering dynamic measuring instrument, and then transmits it to the test computer. The test piece that receives the fluctuation signal, after the fluctuation propagates inside, finally transmits the fluctuation signal to the receiving detector 16. The receiving detector 16 that receives the fluctuation signal transmits the fluctuation signal to the engineering dynamic measuring instrument, and then transmits it to the test computer. The test computer 21 performs data calculation, analysis and processing based on the received data.

[0046] The single vibration method is: manually drive the lever to rotate, and when the lever slides over the lower end of the spring sheet, let go to generate one vibration.

[0047] The vibration excitation device of the present invention is driven by a 12V DC power supply and controls a DC motor through a simple DC speed regulator. The DC motor rotates and is connected to a wheel through a transmission shaft. A wheel lever periodically moves the bottom end of a steel spring sheet fixed at one end. When the lever slides, the spring sheet pops out in the opposite direction under the action of itself and a reset spring. A striking hammer in the middle strikes a vibration pad, and then the vibration pad transmits the vibration to a detector and a test piece, and operates according to the shear wave velocity test method of the prior art.

[0048] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. An automatic excitation system for indoor compaction specimen shear wave velocity testing, characterized in that: The test bracket comprises a test bracket, the test bracket has a trigger mounting end, a receiving mounting end, and a test piece mounting portion located between the trigger mounting end and the receiving mounting end, the test piece mounting portion is mounted with a test piece through a damping pad, the trigger mounting end is mounted with a trigger detector through the damping pad, the trigger detector is located directly below the trigger end of the test piece, the receiving mounting end is mounted with a receiving detector through the damping pad, the receiving detector is matched with the end of the trigger end of the test piece, an excitation pad is provided between the trigger detector and the test piece, the excitation pad is U-shaped, and its two ends are respectively matched with the trigger detector and the trigger end of the test piece; It also includes a vibration excitation mechanism, which is used to strike the middle of the vibration excitation pad so that the wave reaches the test piece and triggers the detector at the same time; The excitation mechanism includes an exciter bracket and a spring sheet and a wheel disc installed on the exciter bracket. The spring sheet is vertically arranged directly above the wheel disc, and a knocking hammer is flatly arranged on the spring sheet. A reset spring is arranged between the spring sheet and the exciter bracket, and the reset spring is arranged opposite to the knocking hammer. The wheel disc is driven to rotate by a driving mechanism, and a lever is provided on the wheel disc. The lever is used to move the lower end of the spring sheet to compress the reset spring and deform the spring sheet. The lever can slide over the spring sheet and continue to rotate with the wheel disc, thereby causing the knocking hammer to knock on the middle part of the excitation pad. After the knocking is completed, the knocking hammer returns to its original position under the action of the reset spring and the spring sheet.

2. The automatic excitation system for the indoor compaction specimen shear wave velocity test according to claim 1, characterized in that: The damping pad with the trigger detector installed at the trigger mounting end of the test bracket is L-shaped, so that the damping pad has a high mounting surface and a low mounting surface. The trigger detector is installed on the low mounting surface, and the excitation pad is installed on the high mounting surface.

3. The automatic excitation system for the shear wave velocity test of indoor compaction specimens according to claim 1, characterized in that: The receiving installation end is fixed with a detector fixture, and the upper and lower parts of the receiving detector are respectively installed on the detector fixture through damping pads.

4. The automatic excitation system for indoor compaction specimen shear wave velocity testing according to claim 1, characterized in that: It also includes a test computer and an engineering dynamic measuring instrument. The trigger detector and the receiving detector are respectively connected to the engineering dynamic measuring instrument. The engineering dynamic measuring instrument is used to collect data from the trigger detector and the receiving detector. The engineering dynamic measuring instrument is connected to the test computer. The test computer performs data calculation, analysis and processing based on the data received by the engineering dynamic measuring instrument.

5. The automatic excitation system for indoor compaction specimen shear wave velocity testing according to claim 1, characterized in that: The driving mechanism comprises a DC power supply, a DC speed regulator and a DC motor which are electrically connected in sequence, and the rotating shaft of the DC motor is dynamically connected to the core shaft of the wheel disc through a transmission shaft.

6. The automatic excitation system for indoor compaction specimen shear wave velocity testing according to claim 1, characterized in that: An anti-skid pad is provided under the test bracket.

7. An automatic excitation method for indoor compaction specimen shear wave velocity testing, characterized in that: The automatic vibration excitation system according to claim 1 is included, and the automatic vibration excitation method is: The wheel rotates, driving the lever to rotate; When the lever rotates to contact the lower end of the spring sheet, the lever continues to rotate and presses down the lower end of the spring sheet, causing the spring sheet to deform under pressure, and at the same time the return spring enters a compressed state, accumulating elastic potential energy; When the lever slides over the lower end of the spring sheet, the reset spring and the spring sheet release elastic potential energy, and the hammer pops out toward the test piece, striking the middle of the exciting pad to generate an exciting vibration, and then the reset spring and the spring sheet return to their original positions, and the wheel continues to rotate, entering the next exciting cycle; The excited vibration pad transmits the vibration to the test piece and triggers the detector at the same time, and the test piece and the trigger detector receive the vibration signal at the same time; The trigger detector that receives the fluctuation signal transmits the fluctuation signal to the engineering dynamic measuring instrument, and then transmits it to the test computer. The test piece that receives the fluctuation signal will eventually transmit the fluctuation signal to the receiving detector after the fluctuation propagates inside it. The receiving detector that receives the fluctuation signal transmits the fluctuation signal to the engineering dynamic measuring instrument, and then transmits it to the test computer. The test computer performs data calculation, analysis and processing based on the received data.

8. The automatic excitation method for indoor compaction specimen shear wave velocity test according to claim 7, characterized in that: The single vibration method is: manually drive the lever to rotate, and when the lever slides over the lower end of the spring sheet, let go to generate one vibration.

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