A probe fixture and method for rock ultrasonic testing

Abstract

The invention discloses a probe fixture and method for rock ultrasonic testing. The fixture comprises a bottom plate, a left bracket, a right bracket, a fixing plate, a pushing plate and a probe placing box. The bottom plate is a rectangular parallelepiped structure, a groove is provided in the middle of the bottom plate, sliding rails are symmetrically provided on both sides of the groove, a crossbeam is fixedly connected to the middle of the groove, and the crossbeam divides the bottom plate into a left half and a right half. Two rows of threaded holes are symmetrically provided on the top of the left half of the bottom plate, and two rows of scales are symmetrically provided on the top of the right half of the bottom plate. The left bracket and the right bracket are rectangular frame structures and are respectively placed in the grooves on both sides of the crossbeam. Pullways slidably connected to the sliding rails are provided at the bottoms of the left bracket and the right bracket. Screws are installed in the left bracket and the right bracket, and a nut is installed on each screw. The probe placing box is installed on the screw and its position is limited by the nut. A circular groove with a notch is provided on the probe placing box. Hooks are symmetrically provided on the crossbeam and the right bracket, and a spring is movably installed between the hooks.

Description

Technical Field

[0001] The invention belongs to the field of rock nondestructive testing, and in particular relates to a probe fixture and a method for rock ultrasonic testing. Background Art

[0002] Rock ultrasonic testing can not only indirectly measure the physical and mechanical parameters of rock samples such as strength parameters, permeability coefficient, rock size, etc., but also classify rocks and non-destructively detect internal damage by detecting the changes in acoustic parameters such as wave velocity, amplitude, waveform and spectrum during the propagation of sound wave signals in rocks. It is widely used in rock engineering because of its advantages such as low test cost, wide test range and fast test speed.

[0003] In actual operation, operators usually need to hold the probe to perform ultrasonic testing on rock samples. However, this method has three main disadvantages, which reduces its testing capability. First, the probe and the sample surface are coated with coupling agent, which makes it easy to slide when the two sides of the clamp are clamped with both hands, resulting in unstable contact surface and increasing the test time; second, the probe and rock sample cannot be aligned, and the relative position offset will lead to increased test errors or even failure; third, during multiple ultrasonic tests, the interaction force between the rock sample and the probe is difficult to maintain consistency, which also causes the test error to increase and reduces its test accuracy. Therefore, designing a probe fixture for rock ultrasonic testing is of great significance to improving test efficiency and accuracy. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a probe fixture and method for rock ultrasonic testing, which can not only fix the probe so that the probe is centered with the rock sample, but also ensure that the interaction force between the probe and the rock sample remains consistent during each ultrasonic test, thereby improving the test accuracy.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A probe fixture for rock ultrasonic testing, comprising a bottom plate, a left bracket, a right bracket, a fixed plate, a push plate and a probe placement box, wherein the bottom plate is a rectangular parallelepiped structure, a groove is arranged in the middle of the bottom plate, slide rails are symmetrically arranged on both sides of the groove, a crossbeam is fixedly connected to the middle of the groove, and the crossbeam divides the bottom plate into a left half and a right half, two rows of threaded holes are symmetrically arranged on the top of the left half of the bottom plate, and two rows of scales are symmetrically arranged on the top of the right half of the bottom plate, and the measurement accuracy is 0.1mm;

[0007] The left bracket and the right bracket are rectangular frame structures and are respectively placed in the grooves on both sides of the crossbeam. The bottoms of the left bracket and the right bracket are provided with pulleys slidably connected to the slide rails. Screws are installed in the left bracket and the right bracket, and a nut is installed on each screw. The probe placement box is installed on the screw and the position is limited by the nut. A circular groove with a notch is provided on the probe placement box. Three hooks are symmetrically provided on the crossbeam and the right bracket, and a spring is movably installed between the hooks.

[0008] The fixing plate is installed on the rear bottom plate of the left bracket through the threaded hole, and the push plate is installed above the fixing plate through a push rod, and the push rod can move left and right to control the push plate to achieve left and right movement.

[0009] Furthermore, the bottom of the left bracket and the right bracket are respectively provided with two circular grooves with self-threaded threads, and the top is provided with a through hole with a larger diameter than the circular groove.

[0010] Furthermore, the diameter of the circular groove in the probe placement box is 40-60 mm, and the probe placement box is provided with a connecting hole for connecting the screw.

[0011] Furthermore, a mounting plate is provided at the bottom of each side bracket of the fixing plate, and each mounting plate is provided with a mounting hole matching the threaded hole.

[0012] The present invention also provides another technical solution as follows:

[0013] A rock ultrasonic testing method comprises the following steps:

[0014] (1) Assemble the fixture, pass the screw through the probe placement box and the nut, and screw it into the threaded holes of the left bracket and the right bracket. After determining the horizontal positions of the two probe placement boxes, turn the nut 10 so that the two probe placement boxes are at the same height, and place the left bracket and the right bracket into the groove of the bottom plate;

[0015] (2) According to the length of the sample to be tested, select the number of springs and hang them between the corresponding hooks;

[0016] (3) In the probe placement box, the ultrasonic probe is embedded in the circular groove with a notch, and the BNC connecting line of the ultrasonic probe is led out through the notch to ensure that the ultrasonic probe is tightly connected to the probe placement box;

[0017] (4) Place the fixed plate and push plate in appropriate positions according to the length of the sample, fix the fixed plate on the bottom plate, move the right bracket to the right for a distance, at which time the spring is in a stretched state, and then place the sample to be tested in the groove between the left bracket and the crossbeam;

[0018] (5) Adjust the pushing length of the push rod so that the push plate pushes the left bracket forward a distance. The moving distance of the right bracket at this time is recorded as x;

[0019] (6) Turn on the ultrasonic measuring instrument, and according to , obtain the interaction force between the two ends of the test sample and the ultrasonic probe as F, where: F is the interaction force between the two ends of the test sample and the ultrasonic probe, n is the number of springs, k is the spring coefficient, and x is the length of the right bracket away from the initial distance;

[0020] (7) After the readings stabilize, move the push rod to retract the push plate, remove the sample to be tested, and repeat steps (5) and (6) for the next test.

[0021] Furthermore, in step (2), if one spring is used, it is hung in the middle position; if two springs are used, they are placed symmetrically front to back; if three springs are used, all of them are placed.

[0022] Furthermore, in step (7), in order to ensure that the interaction force between the test sample and the ultrasonic probe is the same in each test, one of the following conditions should be met:

[0023] A. When the size of the sample to be tested becomes larger, remove the fixing plate and move it to the left side of the bottom plate for a distance and then fix it again. Then, use the push rod to move the push plate forward to fine-tune the right bracket to the same scale as the previous test, that is, to ensure that the interaction force between the ultrasonic probe and the sample to be tested is the same in the two tests;

[0024] B. When the size of the test specimen becomes smaller, remove the fixing plate, move it to the right of the bottom plate for a distance and then fix it again. Then, use the push rod to move the push plate forward to fine-tune the right bracket to the same scale as the previous set of tests, that is, to ensure that the interaction force between the ultrasonic probe and the test specimen is the same in both tests.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] On the one hand, the presence of the brackets on both sides and their screws and nuts ensures that the spatial positions of the two probes are fixed and do not slide relative to each other, thereby ensuring stable contact between the probes and the rock samples during the test and improving the efficiency of the test; on the other hand, by adjusting the height of the nuts on the screws on both sides, the two probes can be stably aligned, increasing the accuracy of the test. In addition, since the bottom plate of the clamp of the present invention has a movable push plate on the left side and a scale line on the right side, during the measurement process, the forward distance of the push plate can be fine-tuned to ensure that the stretching length of the spring remains consistent during each test, thereby further ensuring that the interaction force between the probes at both ends of the sample and the sample surface is consistent during each test, increasing the comparability between each set of test data, which is of great significance to improving the success rate of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1a and Figure 1b They are respectively an overall three-dimensional schematic diagram of the probe fixture and a local three-dimensional schematic diagram of the main parts;

[0028] Figure 2a and Figure 2b They are top views of the left and right halves of the bottom plate respectively;

[0029] Figure 3 It is a three-dimensional schematic diagram and a plan schematic diagram of the framework;

[0030] Figure 4 It is a three-dimensional schematic diagram and a plan schematic diagram of the probe placement box;

[0031] Figure 5 It is a three-dimensional schematic diagram and a plane schematic diagram of the bracket;

[0032] Figure 6a and Figure 6b They are the three-dimensional schematic diagram and the plane schematic diagram of the fixed plate and the push plate respectively.

[0033] Figure markings: 1-threaded hole, 2-hook, 3-slide rail, 4-scale, 5-spring, 6-crossbeam, 7-bracket, 8-screw, 9-frame top hole, 10-nut, 11-hook, 12-pulley, 13-probe placement box, 14-circular groove, 15-through hole, 16-threaded hole, 17-bolt, 18-fixing plate, 19-threaded hole, 20-push plate, 21-circular groove. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] The present invention provides a probe fixture for rock ultrasonic testing, comprising a bottom plate, a left bracket, a right bracket, a fixing plate, a push plate and a probe placement box, Figures 1a to 6b The specific production process of the probe fixture is as follows:

[0036] Step 1: Make a base plate. The base plate is a rectangular parallelepiped with a groove in the middle. The two sides of the groove are provided with left and right slide rails 3. The top of the left half of the base plate is provided with two rows of threaded holes 1, and the top of the right half is provided with two rows of scales 4. The measurement accuracy is 0.1mm.

[0037] Step 2, make three springs 5 ​​and three hooks, weld a rectangular crossbeam 6 in the middle of the groove of the bottom plate in step 1, and set three hooks 2 matching the springs 5 ​​on the right side of the crossbeam;

[0038] Step 3, make two rectangular frame structure brackets 7, the bottom of the bracket 7 is provided with two threaded circular grooves, and the top is provided with two holes slightly larger than the diameter of the bottom circular grooves. The bottom of each bracket 7 is provided with two pulleys 12 matching the slide rail 3, and the bottom of the right bracket 7 is provided with three hooks 11;

[0039] Step 4, make four screws 8, the diameter of the screws 8 is the same as the circular groove at the bottom of the bracket in step 3, and make four nuts 10 that match the screws;

[0040] Step 5, make two probe placement boxes 13. The main body of the probe placement box 13 is a rectangular parallelepiped, and two through holes 15 with a diameter slightly larger than the diameter of the screw 8 are provided in the rear half. A circular groove 14 with a notch is provided in the front half of the probe placement box 13. The diameter of the circular groove 14 is 50 mm, which meets the geometric dimensions of the probe in the general ultrasonic detection device on the market.

[0041] Step 9, make a fixing plate 18, the fixing plate 18 is a square frame structure, the bottom of the fixing plate 18 is provided with four threaded holes 19 of the same specification as the threaded hole 1 on the left side of the bottom plate, and two threaded holes 16 are provided on the fixing plate crossbeam.

[0042] Step 10, making a push plate 20, the push plate 20 is slightly larger than the cross beam of the fixed plate, and two circular grooves 21 with a diameter slightly larger than the threaded hole 16 are provided in the middle of the push plate 20;

[0043] Step 11, screw the screw 8 into the two brackets 7 respectively, and before screwing into the bottom plate of the bracket 7, successively pass the screw 8 through the probe placement box 13 and the nut 10. At this time, the bracket is assembled.

[0044] Step 12, place the two assembled brackets in step 11 into the base plate along the slide rail 3, and fix the fixed plate 18 to the left half of the base plate with screws, screw the bolts 17 on the fixed plate crossbeam to connect the fixed plate and the push plate, and hang the spring between the base plate hook 2 and the frame hook 11. At this time, the probe fixture for the ultrasonic test is assembled.

[0045] Specifically, Figure 1a As shown, based on the ultrasonic testing equipment, the above-made probe fixture is used to test the relevant ultrasonic parameters inside the rock. The corresponding test steps are as follows:

[0046] Step (1), according to the length of the sample to be tested, select the appropriate number of springs 5, and hang them on the hook 2 and the hook 11. If one spring is used, hang it in the middle position, if two are used, place them symmetrically front and back, and if three are used, place all of them;

[0047] Step (2), in the probe placement box 13, the ultrasonic probe is embedded in the circular groove 14 with a notch, and the probe BNC connecting line is led out through the notch to ensure that the ultrasonic probe is tightly connected to the probe placement box 13;

[0048] Step (3): Place the fixing plate and the push plate at appropriate positions according to the length of the sample to be tested, and tighten the screws through the four threaded holes 19 to fix the fixing plate on the bottom plate. Figure 6a As shown, screw the two bolts 17 so that they are inserted into the two circular grooves 21 of the push plate 20. Move to the right Figure 5 The right bracket is shown to be a distance away, at which time the spring is in a stretched state between the two brackets, and then placed ready to wait for the test specimen;

[0049] Step (4), appropriately adjust the pushing length of the bolt 17 so that the push plate pushes the bracket forward by a certain distance, and the moving distance of the right bracket at this time is recorded as x;

[0050] Step (5), at this time, turn on the ultrasonic measuring instrument and start measuring the required physical quantities such as wave velocity and frequency. At this time, the interaction force between the two ends of the sample and the probe is F=nkx; where: F is the interaction force between the two ends of the sample and the probe, n is the number of springs, k is the spring coefficient, and x is the length of the right bracket away from the initial distance.

[0051] Step (6), after the readings are stable, turn the two bolts 17 to retract the push plate 20, and then remove the sample. When performing the next test, repeat steps (4) and (5). It is worth noting that in order to ensure that the interaction force between the sample and the probe is the same during each test, one of the following conditions should be met:

[0052] A. When the size of the test specimen becomes larger, first loosen the screw on the threaded hole 19 at the bottom of the fixing plate, move the fixing plate 18 and the push plate 20 to the left of the bottom plate for a certain distance, and then re-fix them on the threaded hole 1 of the bottom plate. Then, turn the screw on the top of the fixing plate to push the push plate 20 forward so that Figure 5 The right bracket shown is fine-tuned to the same scale as the previous set of tests to ensure that the interaction force between the probe and the sample is the same in both tests.

[0053] B. When the size of the sample to be tested becomes smaller, first loosen the screws on the threaded hole 19 at the bottom of the fixing plate, move the fixing plate 18 and the push plate 20 to the right of the bottom plate for a certain distance, and then re-fix them on the threaded hole 1 of the bottom plate. Then, turn the screws on the top of the fixing plate to push the push plate 20 forward, so that the right bracket is fine-tuned to the same scale as the previous set of tests, which can ensure that the interaction force between the probe and the sample is the same in the two tests.

[0054] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A rock ultrasonic test method, based on a probe fixture for rock ultrasonic testing, comprising a bottom plate, a left bracket, a right bracket, a fixed plate, a push plate and a probe placement box, wherein the bottom plate is a rectangular parallelepiped structure, a groove is provided in the middle of the bottom plate, slide rails are symmetrically provided on both sides of the groove, a crossbeam is fixedly connected to the middle of the groove, and the crossbeam divides the bottom plate into a left half and a right half, two rows of threaded holes are symmetrically provided on the top of the left half of the bottom plate, and two rows of scales are symmetrically provided on the top of the right half of the bottom plate, and the measurement accuracy is 0.1 mm; the left bracket and the right bracket are rectangular frame structures, and are respectively placed in the grooves on both sides of the crossbeam The bottom of the left bracket and the right bracket are each provided with a pulley slidably connected to the slide rail, a screw is installed in the left bracket and the right bracket, a nut is installed on each screw, the probe placement box is installed on the screw and the position is limited by the nut, the probe placement box is provided with a circular groove with a notch, the cross beam and the right bracket are symmetrically provided with three hooks, and a spring is movably installed between the hooks; the fixing plate is installed on the rear bottom plate of the left bracket through the threaded hole, and the push plate is installed above the fixing plate through a push rod, and the push rod can move left and right to control the push plate to achieve left and right movement, characterized in that The following steps are involved: (1) Assemble the fixture, pass the screw through the probe placement box and the nut, and screw it into the threaded holes of the left bracket and the right bracket. After determining the horizontal positions of the two probe placement boxes, turn the nut 10 so that the two probe placement boxes are at the same height, and place the left bracket and the right bracket into the groove of the bottom plate; (2) According to the length of the sample to be tested, select the number of springs and hang them between the corresponding hooks; (3) In the probe placement box, the ultrasonic probe is embedded in the circular groove with a notch, and the BNC connecting line of the ultrasonic probe is led out through the notch to ensure that the ultrasonic probe is tightly connected to the probe placement box; (4) Place the fixed plate and push plate in appropriate positions according to the length of the sample, fix the fixed plate on the bottom plate, move the right bracket to the right for a distance, at which time the spring is in a stretched state, and then place the sample to be tested in the groove between the left bracket and the crossbeam; (5) Adjust the pushing length of the push rod so that the push plate pushes the left bracket forward a distance. The moving distance of the right bracket at this time is recorded as x; (6) Turn on the ultrasonic measuring instrument, and according to F=nkx, the interaction force between the two ends of the test sample and the ultrasonic probe is obtained as F, where: F is the interaction force between the two ends of the test sample and the ultrasonic probe, n is the number of springs, k is the spring coefficient, and x is the length of the right bracket away from the initial distance; (7) After the readings stabilize, move the push rod to retract the push plate, remove the sample to be tested, and repeat steps (5) and (6) for the next test.

2. A rock ultrasonic testing method according to claim 1, characterized in that: In step (2), if one spring is used, hang it in the middle; if two springs are used, place them symmetrically front to back; if three springs are used, place all of them.

3. A rock ultrasonic testing method according to claim 1, characterized in that: In step (7), to ensure that the interaction force between the test sample and the ultrasonic probe is the same during each test, one of the following conditions should be met: A. When the size of the sample to be tested becomes larger, remove the fixing plate and move it to the left side of the bottom plate for a distance and then fix it again. Then, use the push rod to move the push plate forward to fine-tune the right bracket to the same scale as the previous test, that is, to ensure that the interaction force between the ultrasonic probe and the sample to be tested is the same in the two tests; B. When the size of the test specimen becomes smaller, remove the fixing plate, move it to the right of the bottom plate for a distance and then fix it again. Then, use the push rod to move the push plate forward to fine-tune the right bracket to the same scale as the previous set of tests, that is, to ensure that the interaction force between the ultrasonic probe and the test specimen is the same in both tests.

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