Method and equipment for testing elastic modulus of plastic concrete specimens

Abstract

The present invention discloses a method and equipment for testing the elastic modulus of a plastic concrete specimen. The method includes pre-stressing the plastic concrete specimen multiple times, obtaining a deformation value of the plastic concrete specimen, and obtaining a predetermined value until the difference between two adjacent deformation values ​​of the plastic concrete specimens satisfies a predetermined value. The method comprises: driving an upper pressure plate by a servo motor to perform multiple pre-stressing on the plastic concrete specimen; when the difference between two adjacent deformation values ​​of the plastic concrete specimens does not meet the predetermined value, adjusting the position of the plastic concrete specimen on the lower pressure plate by a specimen position adjustment device supported by a test equipment base, and continuing to pre-stress the specimen after the position adjustment. The method of the present invention uses a servo motor as a power source and does not require an oil source. The test process is well controlled, cleaner, and more convenient to use and maintain. It can truly reflect the displacement change of the specimen after being subjected to force, making the elastic modulus test data more accurate. Only one person is required for the test process, saving manpower, reducing labor costs, and improving test efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy projects, and in particular to a method and equipment for performing elastic modulus tests on plastic concrete specimens used in water conservancy projects. Background Art

[0002] Plastic concrete is a highly fluid concrete with a low cement content and high levels of bentonite, clay, and other materials. It exhibits low strength, low elastic modulus, and high strain. As a flexible material, it adapts well to softer foundations while also exhibiting excellent anti-seepage properties. It is widely used in water conservancy projects for anti-seepage purposes. The static compressive modulus is a key mechanical parameter for plastic concrete, reflecting the relationship between the stress and strain it experiences. In water conservancy projects, this is a crucial parameter for plastic concrete mix design. Therefore, prior to using plastic concrete, testing of plastic concrete specimens is necessary.

[0003] At present, the elastic modulus test of plastic concrete in the water conservancy industry generally uses ordinary presses with hydraulic systems as the power source to conduct elastic modulus tests. Figure 1 The press structure shown uses a high-pressure hydraulic source as its power source. The upper pressing plate n, under the action of an external force, comes into contact with the upper surface of the test piece mounted on the lower pressing plate t and then stops. The lower pressing plate then rises under the push of a hydraulic cylinder to squeeze the test piece. A pair of micrometers m are placed on both sides of the lower pressing plate, and the deformation of the plastic concrete specimen during the static compression test is measured by the pair of micrometers. Alternatively, a structure such as that disclosed in Chinese patent number CN202471504U, entitled "Plastic Concrete Full-Scale Static Compression Elastic Modulus Test Frame," is used. Two upper connecting rods are fixed at both ends of the upper pressing plate, and two lower connecting rods are fixed at both ends of the lower pressing plate. The inner end of the two-way connector is connected to the upper connecting rod, and the outer end of the two-way connector is equipped with a measuring device. The measuring head of the measuring device installed on the upper connecting rod through the two-way connector cooperates with the support at the top of the lower connecting rod. The measuring device is a micrometer or a displacement sensor.

[0004] When using the above-mentioned press or test frame to conduct elastic modulus tests on plastic concrete specimens according to the current plastic concrete elastic modulus test procedures, a hydraulic power source is used, and the measurement force range is wide. Therefore, the elastic modulus test of plastic concrete specimens is poor in accuracy and process controllability. The above-mentioned equipment uses a dial indicator to measure the deformation of the specimen. During the test, three people are required to work together: one person controls the testing machine, and two people manually read the dial indicator. This is a huge waste of manpower, high labor costs, and low manual reading accuracy, resulting in large test errors. In addition, the solution of using a two-way connector with an upper connecting rod fixed at one end and a dial indicator or displacement sensor fixed at the other end does not directly apply the force to the dial indicator or displacement sensor. Therefore, the upper connecting rod cannot truly reflect the force applied to the specimen or the deformation of the specimen, and the accuracy is poor. A set of tests are often invalidated and repeated. In addition, the upper and lower positions of the two-way connector need to be adjusted during the test, which is cumbersome to operate, increases test time, and affects test efficiency. In addition, when the difference in deformation value of the specimen during two adjacent pre-stressing does not meet the predetermined value, the position of the specimen needs to be manually adjusted, which takes a long time, increases the labor intensity of the test personnel, and reduces the test efficiency. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a method and equipment for testing the elastic modulus of plastic concrete specimens. The method and equipment adopt a servo motor as the power source instead of an oil source, and the test process is well controlled, cleaner, and more convenient to use and maintain. The method can truly reflect the displacement change of the specimen after being subjected to force, making the elastic modulus test data more accurate. The test process only requires one person, saving manpower, reducing labor costs, and improving test efficiency.

[0006] To achieve the above-mentioned object of the present invention, the present invention provides, on one hand, a method for testing the elastic modulus of a plastic concrete specimen, comprising: performing multiple pre-compressions on the plastic concrete specimen to obtain multiple deformation values ​​of the plastic concrete specimen; and performing a formal elastic modulus test on the plastic concrete specimen when the difference between two adjacent deformation values ​​of the plastic concrete specimen meets a predetermined value, wherein:

[0007] The upper bearing plate is driven by a servo motor to achieve multiple preloading of the plastic concrete specimen so as to accurately control the preloading pressure;

[0008] When the difference between the deformation values ​​of the two adjacent plastic concrete specimens does not meet the predetermined value, adjusting the position of the plastic concrete specimen on the lower bearing plate using a specimen position adjustment device supported by the test equipment base;

[0009] After the position of the plastic concrete specimen on the lower bearing plate is adjusted, the plastic concrete specimen is pre-pressed until the difference between two adjacent deformation values ​​of the plastic concrete specimen meets a predetermined value.

[0010] Preferably, the test piece position adjustment device comprises:

[0011] The controller receives the difference between the deformation values ​​of the two adjacent plastic concrete specimens and is used to control the specimen position adjustment device action mechanism according to the difference so that the specimen position adjustment device action mechanism picks up the plastic concrete specimen and moves it to a corresponding position.

[0012] Preferably, the actuating mechanism of the specimen position adjustment device includes: a horizontal moving mechanism arranged in the base of the test equipment, used for performing horizontal movement according to the control instructions issued by the controller; a lifting mechanism arranged on the horizontal moving mechanism, used for performing lifting operations when the horizontal moving mechanism moves into place; and a clamping mechanism arranged on the lifting mechanism, used for performing clamping operations when the lifting mechanism moves into place.

[0013] Preferably, when the horizontal moving mechanism moves into position, the lifting mechanism performs a lifting operation including:

[0014] When the in-position sensor arranged in the base detects that the horizontal moving mechanism has moved into position, it sends the in-position information of the horizontal moving mechanism to the controller;

[0015] The controller issues an instruction to control the lifting mechanism to perform a lifting operation according to the information that the horizontal moving mechanism is in position, so that the lifting mechanism performs the lifting operation.

[0016] Preferably, when the lifting mechanism moves into position, the clamping mechanism performs a clamping operation including:

[0017] When the in-position sensor arranged in the base or on the lifting mechanism detects that the lifting mechanism has been lifted to the position, it sends the lifting mechanism in-position information to the controller;

[0018] The controller issues an instruction to control the clamping mechanism to perform a clamping operation according to the information that the lifting mechanism is in position, so that the clamping mechanism performs the clamping operation.

[0019] Preferably, the controller issues an instruction to control the clamping mechanism to perform a clamping operation according to the information that the lifting mechanism is in position, and the clamping mechanism performs the clamping operation, which includes:

[0020] After receiving the arrival information sent by the lifting mechanism, the controller issues an instruction to control the clamping mechanism to perform an opening operation, so that the clamping mechanism opens;

[0021] When the fully opened sensor of the clamping mechanism detects that the clamping mechanism is fully opened, it sends fully opened information to the controller;

[0022] The controller issues an instruction to control the lower lateral translation mechanism of the holding translation mechanism to perform a lateral translation operation according to the opening position information, so as to make the lower lateral translation mechanism perform a lateral translation operation in the horizontal direction;

[0023] When the in-position sensor of the lower-layer lateral translation mechanism detects that it has been translated into position, it sends translation-in-position information to the controller;

[0024] The controller issues an instruction to control the clamping mechanism to perform a closing operation according to the translation-into-position information, so that the clamping mechanism performs a clamping operation and clamps the test piece.

[0025] Furthermore, after the clamping mechanism performs the clamping operation and clamps the test piece, the method further includes:

[0026] When the closing position sensor of the clamping mechanism detects that the clamping mechanism is closed and holds the test piece, it sends the closing position information to the controller;

[0027] The controller issues an instruction to control the lifting mechanism to perform a lifting operation according to the clamping in place information, so that the telescopic rod of the lifting mechanism extends upward again in the vertical direction;

[0028] When the in-position sensor of the lifting mechanism detects that the telescopic rod has been extended upward to the position, it sends an extended position information to the controller;

[0029] The controller issues an instruction to control the upper longitudinal translation mechanism of the holding translation mechanism to perform a longitudinal translation operation according to the extended in-position information, so as to make the upper longitudinal translation mechanism perform longitudinal translation along the horizontal direction;

[0030] When the in-position sensor of the upper longitudinal translation mechanism detects that it has been translated into position, it sends translation in-position information to the controller;

[0031] The controller issues an instruction to control the clamping mechanism to open according to the information that the upper longitudinal translation mechanism has been translated into position, so as to open the clamping mechanism and move the test piece to a desired position.

[0032] Preferably, obtaining the deformation value of the plastic concrete specimen by pre-compressing the plastic concrete specimen includes:

[0033] When the servo motor drives the upper bearing plate to realize pre-compression of the plastic concrete specimen, a pair of measuring rods on both sides of the upper bearing plate move along with the upper bearing plate;

[0034] When a pair of measuring rods on both sides of the upper pressure plate moves with the upper pressure plate, a pair of grating scale assemblies on both sides of the lower pressure plate corresponding to the positions of the pair of measuring rods respectively detect the deformation values ​​on both sides of the plastic concrete specimen and transmit the deformation values ​​to the controller.

[0035] Preferably, the controller receives the difference between two adjacent deformation values ​​of the plastic concrete specimen and controls the actuating mechanism of the specimen position adjustment device according to the difference so that the actuating mechanism of the specimen position adjustment device picks up the plastic concrete specimen and moves it to the corresponding position, including:

[0036] After receiving the difference between two adjacent deformation values ​​of the plastic concrete specimen, the controller determines whether the difference meets a predetermined value;

[0037] If the difference does not meet the predetermined value, the controller compares the received deformation values ​​of the two sides of the plastic concrete specimen during the current preloading to obtain the side with smaller deformation between the two sides of the plastic concrete specimen;

[0038] After obtaining the side with smaller deformation of the plastic concrete specimen, the controller controls a pair of specimen position adjustment device action mechanisms to lift the plastic concrete specimen and move it toward the side with smaller deformation until it moves to a corresponding position.

[0039] On the other hand, the present invention also provides an apparatus for testing the elastic modulus of plastic concrete specimens according to the method described above, comprising: a test frame having a base, an upper pressure plate, a lower pressure plate, and an upper pressure plate driving device, wherein the power source of the upper pressure plate driving device is a servo motor that can accurately control the prestressing pressure; a specimen position adjustment device is provided on the base, which is used to adjust the position of the plastic concrete specimen on the lower pressure plate when the plastic concrete specimen is prestressed multiple times and the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet a predetermined value.

[0040] Preferably, the specimen position adjustment device includes: an action mechanism for picking up the plastic concrete specimen and moving it to a corresponding position when the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet a predetermined value; and a controller for receiving the difference between the deformation values ​​of two adjacent plastic concrete specimens, and for controlling the action mechanism according to the difference.

[0041] Furthermore, it also includes a plastic concrete specimen deformation detection device, which includes: a pair of measuring rods installed on both sides of the upper pressure plate; a pair of grating scale assemblies fixedly installed on both sides of the lower pressure plate and corresponding to the positions of the pair of measuring rods for obtaining the deformation values ​​on both sides of the specimen when the specimen is pre-stressed.

[0042] Preferably, the action mechanism includes: a horizontal moving mechanism arranged in the base of the test equipment, used for horizontal movement according to the control instructions issued by the controller; a lifting mechanism arranged on the horizontal moving mechanism, used for performing lifting operations when the horizontal moving mechanism moves into place; and a clamping mechanism arranged on the lifting mechanism, used for performing clamping operations when the lifting mechanism moves into place.

[0043] Preferably, a pair of servo motors are provided on both sides of the interior of the base, and each servo motor is connected to one side of the beam for fixing the upper pressure plate through a transmission mechanism.

[0044] Preferably, the test stand further comprises a pair of support frames vertically mounted on both sides of the base and a pair of guide rails fixedly mounted on opposite sides of the pair of support frames; the crossbeam can be raised and lowered along the pair of guide rails.

[0045] Preferably, a ball joint support is installed on the upper surface of the base, and the lower part of the lower pressure plate is hinged to the ball joint support.

[0046] Preferably, the transmission mechanism is a screw-nut transmission mechanism, and the nut thereof is fixedly connected to one side of the crossbeam.

[0047] Preferably, a pair of connecting seats are symmetrically arranged on both sides of the upper pressure plate, and vertical through holes are opened on the connecting seats, and each measuring rod passes through the through hole of the corresponding side connecting seat.

[0048] Preferably, a screw hole perpendicular to the axial direction of the through hole is provided on the connecting seat, and a bolt for fastening the measuring rod passing through the through hole is screwed into the screw hole.

[0049] Compared with the prior art, the method and equipment for testing the elastic modulus of plastic concrete specimens of the present invention have the following advantages:

[0050] 1. The method and equipment for testing the elastic modulus of plastic concrete specimens of the present invention adopt a servo motor as a power source, do not require an oil source, are cleaner, and are more convenient to use and maintain. The servo motor drives the crossbeam to move to achieve movement of the upper bearing plate, so that the test speed and stroke can be determined as needed, the test process is well controllable, and the test is more flexible. The servo motor is placed in the base, making the overall structure compact and smaller in size.

[0051] 2. The equipment of the present invention has an adjustable distance between the upper and lower pressure plates, which facilitates the installation of plastic concrete specimens. An electronic grating scale assembly and a measuring rod are used to measure the displacement value of the plastic concrete specimen during the test, which can truly reflect the displacement value of the specimen after being subjected to force, making the elastic modulus test data more accurate. In addition, the position of the measuring rod relative to the upper pressure plate is adjustable, which facilitates elastic modulus testing of specimens of different heights.

[0052] 3. The equipment of the present invention can automatically adjust the position of the plastic concrete specimen on the lower pressure plate when the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet the predetermined value during the process of multiple pre-compression of the plastic concrete specimen, thereby reducing the labor intensity of the operator and improving the test efficiency.

[0053] 4. The equipment of the present invention only requires one person to complete the test during the test process. Compared with the existing technology that requires three professional technicians to participate simultaneously, it greatly saves manpower, reduces labor costs, improves test efficiency, meets the current testing needs of large quantities of high-standard plastic concrete specimens, and can provide timely and effective test data for engineering projects. Automatically completing the test can significantly reduce test errors, improve the accuracy of test results, improve test efficiency and reduce testing costs, so that the timeliness of the data acquisition of engineering projects is guaranteed, thereby effectively controlling the quality of the project and protecting the quality of the project.

[0054] The present invention will be described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a partial schematic diagram of a conventional full-scale static compressive elastic modulus testing machine for plastic concrete;

[0056] Figure 2a 1 is a structural schematic diagram of the elastic modulus test device for plastic concrete specimens of the present invention in one state (the clamping mechanism of the specimen position adjustment device, etc., does not extend from the base);

[0057] Figure 2b It is a structural schematic diagram of the device of the present invention in another state (the holding mechanism of the specimen position adjustment device and the like extends out of the base);

[0058] Figure 3 It is a partial enlarged schematic diagram of the upper pressure plate and the lower pressure plate in the device of the present invention;

[0059] Figure 4 It is a partial enlarged schematic diagram of the servo motor driving the crossbeam in the device of the present invention;

[0060] Figure 5a 、 Figure 5b Schematic diagram of the structure of the test piece position adjustment device of the present invention in two different installation positions relative to the lower bearing plate;

[0061] Figure 6 It is a structural schematic diagram of the horizontal moving mechanism of the present invention;

[0062] Figure 7a This is a structural diagram of the clamping mechanism of the present invention;

[0063] Figure 7b 、 7c It is a schematic diagram of the structure of another structure of the holding mechanism of the present invention when it is in different positions relative to the lifting mechanism;

[0064] Figure 8 This is a schematic diagram of the first structure of the lifting mechanism of the present invention;

[0065] Figure 9 yes Figure 8 Schematic diagram of the telescopic part;

[0066] Figure 10 It is a structural schematic diagram of the holding and translation mechanism of the present invention;

[0067] Figure 11 This is a schematic diagram of the structure of the clamping mechanism of the present invention using an electric clamping claw;

[0068] Figure 12a This is a schematic diagram of the present invention using electric clamping claws to clamp a test piece;

[0069] Figure 12b This is a schematic diagram of the present invention using hydraulic clamping claws to clamp a test piece;

[0070] Figure 13 This is a control structure diagram when the deformation values ​​of two adjacent pre-compression test pieces do not meet the predetermined values ​​in the test method of the present invention;

[0071] Figure 14 This is a schematic diagram of the principle of determining whether to adjust the position of a specimen according to the deformation values ​​of the specimen after two adjacent pre-compression tests during the present invention;

[0072] Figure 15 It is a flow chart of the elastic modulus test method of the plastic concrete specimen of the present invention. DETAILED DESCRIPTION

[0073] Before conducting the formal static compressive elastic modulus test (referred to as elastic modulus test) of the plastic concrete specimen, the plastic concrete specimen needs to be pre-stressed multiple times to obtain multiple deformation values ​​of the plastic concrete specimen until the difference between the deformation values ​​of two adjacent plastic concrete specimens meets the predetermined value, such as 0.006mm (or 0.005mm). Otherwise, the pre-stressing should continue until the difference meets the requirement, and then the formal elastic modulus test of the plastic concrete specimen can be carried out.

[0074] Since the interior of the plastic concrete specimens used in water conservancy projects is composed of sand and gravel aggregates, it is difficult to ensure that the force center of the specimen is the geometric center of the specimen during the preloading process of the elastic modulus test. This requires the specimen to be preloaded multiple times. When the specimen is preloaded multiple times, the difference in the deformation values ​​of two adjacent plastic concrete specimens will repeatedly fail to meet the predetermined value. In the prior art, the operator is required to repeatedly stop the machine and perform manual adjustments. Repeatedly performing such operations greatly increases the operator's labor intensity and affects the test process. To solve this problem, the present invention uses a specimen position adjustment device supported by the base of the test equipment to adjust the position of the plastic concrete specimen on the lower pressure plate. In addition, in order to avoid the need for an oil source and make the test process more controllable and cleaner, the present invention uses a servo motor as a power source. The servo motor drives the upper pressure plate to achieve multiple preloading and formal testing of the plastic concrete specimen, thereby accurately controlling the preloading pressure and formal test pressure, making the elastic modulus test data more accurate.

[0075] Specifically, such as Figure 15 As shown, the method for testing the elastic modulus of a plastic concrete specimen adopted by the present invention includes performing multiple pre-compression on the plastic concrete specimen to obtain multiple deformation values ​​of the plastic concrete specimen. When the difference between the deformation values ​​of two adjacent plastic concrete specimens meets a predetermined value, a formal elastic modulus test of the plastic concrete specimen is performed, wherein:

[0076] The upper bearing plate is driven by a servo motor to achieve multiple preloading of the plastic concrete specimen so as to accurately control the preloading pressure;

[0077] When the difference between the deformation values ​​of the two adjacent plastic concrete specimens does not meet the predetermined value, adjusting the position of the plastic concrete specimen on the lower bearing plate using a specimen position adjustment device supported by the test equipment base;

[0078] After the position of the plastic concrete specimen on the lower bearing plate is adjusted, the plastic concrete specimen is pre-pressed until the difference between two adjacent deformation values ​​of the plastic concrete specimen meets a predetermined value.

[0079] Wherein, the present invention adopts Figure 2a 、 Figure 2b The elastic modulus test equipment for plastic concrete specimens shown in the figure is used to test the elastic modulus of plastic concrete specimens ( Figure 2a 、 Figure 2b Schematic diagrams showing the test equipment of the present invention in different states respectively).

[0080] As can be seen from the figure, the elastic modulus test equipment of the plastic concrete specimen of the present invention includes: a test frame with a base 1a, an upper pressure plate 5, a lower pressure plate 3 and an upper pressure plate driving device, wherein the power source of the upper pressure plate driving device is a servo motor that can accurately control the preloading pressure; a specimen position adjustment device is provided on the base, which is used to adjust the position of the plastic concrete specimen on the lower pressure plate when the plastic concrete specimen is preloaded multiple times and the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet the predetermined value.

[0081] Specifically, such as Figure 2a-Figure 4 As shown, the test stand of the present invention includes a frame 1, which includes a base 1a, a pair of support frames 1b vertically installed on both sides of the base, a top beam 1d fixedly connected to the top of the pair of support frames at both ends, and a pair of vertical guide rails 1c fixedly installed on opposite sides of the pair of support frames (see Figure 4 An upper bearing plate and a lower bearing plate are mounted on the frame. The upper bearing plate can be moved up and down along a pair of guide rails driven by an upper bearing plate driving device to perform an extrusion test on a plastic concrete specimen placed on the lower bearing plate.

[0082] Among them, the upper pressure plate driving device includes a pair of motor driving devices, each motor driving device includes a servo motor, a transmission mechanism connected to the servo motor, and a beam connected to a pair of transmission mechanism output elements, and the upper pressure plate is fixedly installed under the beam.

[0083] The base adopts a box-type structure, and a servo motor 71 is fixedly installed on both sides of the inside. The output shaft of each servo motor is connected to the transmission mechanism. The transmission mechanism can adopt a screw-nut transmission mechanism, a gear rack transmission mechanism, or a mechanism that converts rotation into linear motion using existing technology. The present invention preferably adopts a screw-nut transmission mechanism, whose screw 72 is connected to the output shaft of the servo motor or the output shaft of the reduction mechanism and extends in the vertical direction. During assembly, the screw is placed in the support frame and extends in the height direction of the support frame, and its nut 73 is fixedly connected to the corresponding side of the beam 74. When a pair of servo motors rotate synchronously, the nuts on their respective screws drive the beam to move up and down along the guide rails on the support frame. The lower part of the beam is connected to the upper pressure plate. When connected, a connecting seat 75 can be set at the center position of the lower part of the beam (see Figure 4 ), the upper bearing plate and the connecting base are fixed together by bolts. Furthermore, a load sensor can be installed on the connecting base to detect the pressure applied by the upper bearing plate during testing. Driven by a pair of servo motors, the crossbeam moves vertically, driving the upper bearing plate up and down. As the upper bearing plate moves downward, it applies a compressive force to the top of the plastic concrete specimen placed on the lower bearing plate, achieving both preload and final testing for the elastic modulus test.

[0084] A support 2 is fixedly mounted at the center of the upper surface of the base, with its upper portion connected to the lower portion of the lower bearing plate. To automatically adjust the specimen position based on the surface conditions during elastic modulus testing of plastic concrete specimens, this support is hinged to the lower portion of the lower bearing plate using a spherical hinge.

[0085] In order to truly reflect the displacement value generated by the specimen after being subjected to force during the test, the equipment of the present invention also includes a plastic concrete specimen deformation detection device, which includes: a pair of measuring rods 6 installed on both sides of the upper pressure plate; a pair of grating scale assemblies 11 fixedly installed on both sides of the lower pressure plate and corresponding to the positions of the pair of measuring rods for obtaining the deformation values ​​on both sides of the specimen when the specimen is pre-stressed.

[0086] The present invention features a pair of symmetrical connecting blocks 51 on either side of the upper bearing plate. Each of these blocks has a vertical through-hole, through which a cylindrical measuring rod is inserted. Furthermore, a pair of grating scale assemblies are fixedly mounted on either side of the lower bearing plate, positioned directly below the measuring rods.

[0087] To allow the height of the measuring rod relative to the lower bearing plate to be adjusted according to test requirements, a threaded hole is provided on the outer wall of each connecting base, perpendicular to the axis of the through-hole. A bolt (or screw) is threaded into the hole. The end of the bolt extends into the threaded hole and rests against the outer wall of the measuring rod extending through the through-hole, thereby securing the measuring rod to the connecting base. During design, the end of the bolt can be machined into a curved surface that matches the outer surface of the measuring rod. Of course, other conventional structures can also be used to secure the measuring rod to the connecting base.

[0088] When a specimen is to be subjected to an elastic modulus test, the specimen is placed on the lower pressure plate, and a pair of servo motors synchronously drive the upper pressure plate downward until it contacts the specimen's upper surface. The distance between the measuring rods and the corresponding grating scale assemblies on the lower pressure plate is then adjusted by adjusting the depth of the bolts screwed into the connection seat screw holes on both sides of the upper pressure plate, so that the lower ends of the pair of measuring rods can respectively contact the upper surfaces of the pair of grating scale assemblies. When the servo motor drives the upper pressure plate downward to squeeze the specimen in accordance with the test procedure, the pair of grating scale assemblies can capture the displacement changes occurring on the corresponding sides of the specimen when it is squeezed in real time.

[0089] The displacement information collected by the pair of scale assemblies is transmitted to a data acquisition device 9, which is connected to the pair of scale assemblies via a cable or wirelessly. This data acquisition device receives and processes the displacement information transmitted by the pair of scale assemblies and transmits it to a controller 10. When the specimen is preloaded multiple times and the difference in displacement between two consecutive specimen deformations exceeds a predetermined value, the controller controls the specimen position adjustment device to perform the corresponding operation, lifting the plastic concrete specimen on the lower bearing plate and moving it to the appropriate position. The relevant results are displayed on a display screen 8, allowing test personnel to obtain real-time displacement and elastic modulus.

[0090] Among them, the specimen position adjustment device for adjusting the specimen position of the present invention includes: an action mechanism for picking up the plastic concrete specimen and moving it to the corresponding position when the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet a predetermined value; a controller for receiving the difference between the deformation values ​​of two adjacent plastic concrete specimens, and for controlling the action mechanism according to the difference.

[0091] Among them, Figure 7a 、 Figure 7b 、 Figure 7c As shown, the actuating mechanism of the specimen position adjustment device of the present invention includes: a horizontal moving mechanism arranged in the base of the test equipment, used for horizontal movement according to the control instructions issued by the controller; a lifting mechanism arranged on the horizontal moving mechanism, used for lifting and lowering operations when the horizontal moving mechanism moves into place; and a clamping mechanism arranged on the lifting mechanism, used for clamping operations when the lifting mechanism moves into place.

[0092] Specifically, a horizontal track 300 is provided in the base of the test equipment, and the horizontal moving mechanism moves horizontally along the horizontal track. During design, the horizontal track 300 is placed on one side of the interior of the base, and has a pair of first guide rails 301. The pair of first guide rails extend in a direction parallel to the radial direction of the lower pressure plate, and the ends thereof may intersect with the extension line of the central axis of the lower pressure plate. The horizontal track 300 may be provided on the rear side of the lower pressure plate (e.g. Figure 5a As shown), it can also be set on the left side of the lower pressure plate (as shown Figure 5b No matter which position is set, a placement groove for placing the specimen position adjustment device must be set at the corresponding position inside the base. When the specimen position needs to be adjusted, part of the mechanism of the specimen position adjustment device can be extended from the base (such as Figure 2b When the position of the specimen does not need to be adjusted, the various parts of the specimen position adjustment device can be partially or completely hidden in the base (as shown). Figure 2aIt should be noted that when setting the placement slot, it is necessary to ensure that there is a sufficient distance between the opening on the upper surface of the base and the outer edge of the support for supporting the lower pressure plate to allow safe testing without affecting the test results. In addition, the length of the horizontal track and the distance between it and the pair of servo motors installed in the base for driving the movement of the upper pressure plate should be reasonably determined so that the specimen position adjustment device does not affect the normal progress of the test.

[0093] Among them, the horizontal moving mechanism of the present invention can adopt the following method: Figure 6 The structure shown includes: a first slide 201 positioned on a pair of first guide rails; a first drive structure connected to the first slide for driving it to translate along the first guide rails, comprising a first motor 303 and a first screw drive assembly 302 in transmission connection with the first motor, the nut of the first screw drive assembly being fixedly connected to the bottom of the first slide. The first motor operates upon receiving a command to control its movement, driving the first slide to translate along the horizontal track so as to move from an initial position (i.e., a position away from the center of the base) to a desired position (i.e., a position near the center of the base), thereby driving the lifting mechanism and clamping mechanism mounted thereon to move horizontally to the desired position. Alternatively, the horizontal movement mechanism may employ other mechanisms of the prior art.

[0094] Among them, the lifting mechanism of the present invention can be adopted as follows Figure 8 、 Figure 9The illustrated structure includes: a housing 202 fixedly mounted on the upper surface of a first slide 201; a telescopic rod 204 positioned outside the housing; a sleeve 203 positioned within the housing; and a lifting mechanism positioned within the housing for driving the telescopic rod to telescope vertically. The lifting mechanism includes: a second motor 241 positioned on one side of the sleeve; a transmission assembly 242 (which may be a gear transmission assembly or other transmission assembly) connected to the output shaft of the second motor; a screw 243 connected to the power output shaft of the transmission assembly, positioned within the sleeve and coaxial with the sleeve; a nut 244 threadedly connected to the screw; and a connecting sleeve 245 extending from the outside of the screw and having a diameter greater than the screw's outer diameter. The connecting sleeve is positioned above the nut, with its lower surface connected to the nut and its upper surface fixedly connected to the lower portion of the telescopic rod 204. When the second motor (which may be a servo drive motor) is in operation, the transmission assembly drives the screw. The screw's rotation causes the nut, which is threadedly connected to it, to move up and down along its axis. The up and down movement of the nut drives the connecting sleeve along the screw. During the design process, the outer diameter of the nut is smaller than that of the connecting sleeve, which is larger than that of the telescopic rod. A through hole for the screw is provided in the center of the telescopic rod. A guide groove (not shown) is provided on the inner wall of the sleeve so that the connecting sleeve moves along the guide groove of the sleeve. In this way, the connecting sleeve and the telescopic rod move up and down along the screw under the push of the nut. During the design process, a placement cavity (not shown) for placing the corresponding components can be provided in the first slide seat. The second motor is installed above the first slide seat, the transmission assembly is placed in the placement cavity, and the bottom of the sleeve is fixedly connected to the upper surface of the first slide seat. The present invention can also adopt other lifting structures in the prior art to drive the telescopic rod to move telescopically relative to the sleeve, which will not be described in detail here.

[0095] The clamping mechanism of the present invention can be directly mounted on the top of the telescopic rod 204 (e.g. Figure 7a As shown), it is also possible to hold the translation mechanism 205 (as shown Figure 10 As shown) connected to the telescopic rod (as shown) Figure 7b 、 Figure 7c As shown), preferably, the present invention adopts a structure in which a clamping translation mechanism is connected to the telescopic rod, so that after the telescopic rod is raised and lowered into place, the clamping mechanism can be translated horizontally relative to the telescopic rod toward the test piece, thereby clamping the test piece.

[0096] Specifically, the holding mechanism can be adopted as follows Figure 7b 、 Figure 7c 、 Figure 11-12b The structure shown in FIG. 1 includes: a fixing seat 207; a clamping assembly mounted on the fixing seat and capable of opening and closing. The clamping assembly of the present invention can be used as follows: Figure 11 、 Figure 12aThe electric clamping assembly shown includes: a clamping frame 264, in which a pair of arc-shaped slides are symmetrically arranged; a pair of arc-shaped clamping claws 265, respectively placed on the pair of slides and movable along the slides, which can extend from the clamping frame to open to hold or retract into the clamping frame; a linear guide 262 mounted on a fixed seat and fixedly connected to one side of the clamping frame; a slide 263 slidably connected to the linear guide, the slide being hinged to one end of the pair of clamping claws through a pair of connectors; a motor drive assembly that drives the slide to reciprocate on the linear guide, including a third motor and a screw transmission mechanism. During the design, two vertical plates are set on the fixed seat 207 at both ends of the linear guide, and the two ends of a screw are rotatably connected to the two vertical plates. A third motor 261 for driving the screw to rotate is installed on the outside of one of the vertical plates, and the screw is fixedly connected to the bottom of the slide. When the specimen needs to be held, the third motor drives the screw to rotate, which can drive the slide to move back and forth along the linear guide rail, thereby driving a pair of clamping claws to slide back and forth along the slide through the connecting piece, thereby controlling the opening and closing of the pair of clamping claws.

[0097] Alternatively, the clamping assembly may be formed as Figure 12b The hydraulic clamping assembly shown in the figure includes a clamping base 268 with a pair of symmetrical clamping rods extending in opposite directions along an arc; a hydraulic cylinder 267 mounted on the clamping rods; and a pair of grippers 266 fixedly connected to the ends of the hydraulic cylinder piston rods. The bottom of the clamping base can be fixedly mounted on a fixed base, while the opposing surfaces of the pair of grippers are curved to align with the outer surface of the specimen. The grippers are designed to be removably connected to the ends of the piston rods, and the curved surfaces of the grippers can be designed with different radii. This allows the grippers to be replaced according to specimen diameters, allowing elastic mold tests to be performed on different specimens using the same equipment.

[0098] Regardless of the structure of the clamping assembly, the dimensions of each component can be reasonably determined according to actual conditions, especially the height of the clamping claws or grippers, so that the specimen can be held securely and moved to the desired position.

[0099] When the clamping mechanism is connected to the telescopic rod through the clamping translation mechanism 205, the fixing seat of the clamping mechanism is fixedly connected to the translation seat 253 of the clamping translation mechanism. Figure 10 The structure shown includes a lower-level transverse translation mechanism and an upper-level longitudinal translation mechanism.

[0100] The lower lateral translation mechanism comprises: a lower connecting base 254, fixedly connected to the top of the telescopic rod 204, with slide rails on either side extending radially parallel to the lower pressure plate; a lower translation base 253, slidably connected to the connecting base; and a lower drive assembly that drives the lower translation base back and forth along the lower connecting base. This can be a motor drive assembly, comprising a fourth motor 251, a screw drive assembly 252, which is transmission-connected to the fourth motor, and a nut of the screw drive assembly is fixedly connected to the lower translation base. Alternatively, a hydraulic drive assembly can be used. The upper longitudinal translation mechanism comprises: an upper connecting base 257, fixedly connected to the top surface of the lower translation base 253, with its upper rails extending perpendicular to the direction of the lower connecting base's slide rails; an upper translation base 256, slidably connected to the upper connecting base; and an upper drive assembly that drives the upper translation base back and forth along the upper connecting base. This can also be a motor drive assembly, comprising a fifth motor 255, a screw drive assembly, which is transmission-connected to the fifth motor, and a nut of the screw drive assembly is fixedly connected to the bottom of the upper translation base. The upper surface of the upper translation seat is fixedly connected to the fixed seat 207 of the clamping mechanism, or the upper translation seat and the fixed seat are integrally formed. The clamping translation mechanism allows the clamping assembly of the clamping mechanism to be moved horizontally relative to the telescopic rod (i.e., toward or away from the specimen) to open or close, and the clamping mechanism can also be moved horizontally and longitudinally around the specimen to hold it in a desired position.

[0101] Among them, during the operation of the above-mentioned action mechanisms, in order to facilitate the accurate determination of the moving position of each action mechanism, an in-position detection component for detecting when each action mechanism reaches the required position after executing the instruction and a return detection component for detecting when each action mechanism returns to the initial position can be set on the corresponding component. For example, an in-position detection component (or in-position sensor) for detecting when the first slide moves horizontally to a desired position and a return detection component (or return sensor) for detecting when the first slide returns to an initial position are provided on the horizontal track and / or the base and / or the first slide; an in-position detection component for detecting whether the telescopic rod of the lifting mechanism is extended to a desired height and a return detection component for detecting when the telescopic rod returns to the initial position are provided on the base and / or the lifting mechanism; an in-position detection component and a return detection component for detecting whether the upper connecting base moves horizontally to a desired position and returns to the initial position on the lower translation seat are provided on the lower translation seat and / or the upper connecting base; corresponding in-position detection components and return detection components are provided on the upper translation seat and / or the fixed seat of the clamping mechanism; corresponding in-position detection components for detecting when the clamping claw or gripper is opened to a desired position and a return detection component for detecting when the clamping claw or gripper is closed to the initial position are provided on the clamping claw and / or the fixed seat and / or the slide, etc.

[0102] Among them, the above-mentioned in-position detection components and return detection components can all use existing technology sensors that can prompt in-position and return, and the installation position of each sensor is determined according to actual conditions, which will not be described in detail here.

[0103] It should be noted that the initial positions to which the aforementioned mechanisms can return refer to the initial positions of the mechanisms when the specimen position adjustment device does not need to perform the corresponding action. That is, during the multiple preloading processes of the elastic modulus test of the plastic concrete specimen, the difference in deformation values ​​of two adjacent plastic concrete specimens obtained meets the predetermined requirements, and therefore the initial positions of the mechanisms do not need to be adjusted on the lower pressure plate. When the difference in deformation values ​​of two adjacent plastic concrete specimens does not meet the predetermined requirements, the aforementioned mechanisms will move to the desired positions accordingly. The distance that each mechanism moves from the initial position to the desired position can be reasonably determined based on actual conditions.

[0104] During assembly, the opening and closing direction of the clamping assembly of the clamping mechanism should correspond to the direction of the specimen placed on the lower pressure plate, so that the clamping assembly can hold the specimen from both sides when it is opened and closed (e.g. Figure 12a 、 Figure 12b shown).

[0105] The following describes in detail the method for conducting an elastic modulus test of a plastic concrete specimen using the apparatus of the present invention.

[0106] S01. The upper bearing plate is driven by a servo motor to achieve multiple preloading of the plastic concrete specimen so as to accurately control the preloading pressure.

[0107] Before the test, the plastic concrete specimen is placed on the lower pressure plate of the test equipment, and then a pair of servo motors arranged on both sides of the base drive the upper pressure plate to move downward to pre-compress the plastic concrete specimen multiple times.

[0108] During the preloading process, the servo motor speed is controlled according to the preset pressure, so that the descending distance of the upper pressure plate driven by the servo motor can be accurately controlled, so that the upper pressure plate can accurately preload the plastic concrete specimen according to the preset pressure, thereby improving the accuracy of the elastic modulus test.

[0109] S02. During multiple pre-compression tests on the plastic concrete specimen, multiple deformation values ​​of the plastic concrete specimen are obtained until a difference between two adjacent deformation values ​​of the plastic concrete specimens meets a predetermined value.

[0110] During the preloading test of the plastic concrete specimen driven by the servo motor to drive the upper bearing plate, the deformation values ​​on both sides of the plastic concrete specimen during each preloading must be detected, including:

[0111] When the servo motor drives the upper pressure plate to move downward, a pair of measuring rods installed on both sides of the upper pressure plate will also move downward with the upper pressure plate;

[0112] When the upper bearing plate applies extrusion force to the plastic concrete specimen to cause the specimen to be compressed and deformed, under the control of the specimen deformation acquisition control unit, a pair of grating scale assemblies (i.e., Figure 14 The first grating scale assembly and the second grating scale assembly shown in the figure will work, and the acquisition module of the grating scale assembly will collect the data changes caused by the compression of the corresponding measuring rod and obtain the deformation values ​​on both sides of the plastic concrete specimen.

[0113] After obtaining the deformation values ​​on both sides of the specimen during each preloading through a pair of grating scale assemblies, the deformation values ​​will be processed, and the difference in deformation values ​​of the plastic concrete specimen during each two adjacent preloading times during multiple preloading times will be sent to the controller. The controller receives the difference in the above deformation values ​​and controls the specimen position adjustment device action mechanism according to the difference, so that the specimen position adjustment device action mechanism can pick up the plastic concrete specimen and move it to the corresponding position.

[0114] Among them, Figure 13 、 Figure 14 As shown in the figure, after obtaining the deformation values ​​on both sides of the specimen during each preloading through a pair of grating scale assemblies, the deformation values ​​will be processed including:

[0115] A pair of deformation values ​​on both sides of the plastic concrete specimen at each preloading are averaged to obtain the deformation value of the plastic concrete specimen after each preloading.

[0116] The difference calculation is performed on the deformation values ​​of the plastic concrete specimens that are averaged after each two adjacent preloading to obtain the difference between the deformation values ​​of the two adjacent plastic concrete specimens.

[0117] The averaging of a pair of deformation values ​​on both sides of the plastic concrete specimen during each preloading step includes:

[0118] The deformation value of one side of the plastic concrete specimen during each preloading is collected by the first collection module of the first grating ruler assembly;

[0119] The deformation value of the other side of the plastic concrete specimen during the preloading is collected by the second collection module of the second grating ruler assembly;

[0120] The average value of a pair of deformation values ​​on both sides of the plastic concrete specimen obtained during each preloading is calculated through an averaging module, thereby obtaining the deformation value of the plastic concrete specimen that has been averaged during the preloading.

[0121] The average value of the obtained pair of deformation values ​​can be calculated by using the mean square error or other methods in the prior art, which will not be described in detail here.

[0122] The controller receives the difference in deformation values ​​of the plastic concrete specimen after two adjacent pre-compressions, and controls the actuating mechanism of the specimen position adjustment device according to the difference, so that the actuating mechanism of the specimen position adjustment device picks up the plastic concrete specimen and moves it to the corresponding position, including:

[0123] After receiving the difference between the deformation values ​​of two adjacent plastic concrete specimens, the controller determines whether the difference meets a predetermined value;

[0124] If the difference meets the preset value, the controller issues an instruction for the equipment to enter the formal elastic modulus test of the plastic concrete specimen, and the equipment performs the formal elastic modulus test on the specimen;

[0125] If the difference does not meet the predetermined value, the controller compares the deformation values ​​of the two sides of the plastic concrete specimen during the current preloading, and obtains the side with the smaller deformation (i.e., the side with the smaller value in a pair of deformation values). Then, the controller controls the motion mechanism of the specimen position adjustment device to lift the plastic concrete specimen and move it toward the side with the smaller deformation until it moves to the corresponding position. The specimen position adjustment device then returns to its original position, and the specimen continues to be preloaded through the upper pressure plate until the difference in deformation values ​​between two adjacent preloading times meets the predetermined value.

[0126] When the difference between the deformation values ​​of two adjacent preloading operations does not meet a predetermined value, the controller controls the action mechanism of the specimen position adjustment device to lift the plastic concrete specimen and move it toward the side with smaller deformation until it moves to the corresponding position.

[0127] The horizontal moving mechanism provided in the base of the test equipment moves horizontally according to the control instruction issued by the controller, so that the test piece position adjustment device moves from the initial position to the preset position along the horizontal direction under the drive of the horizontal moving mechanism;

[0128] After the specimen position adjustment device reaches the preset position from the initial position in the horizontal direction, the lifting mechanism provided on the horizontal moving mechanism performs a lifting operation, so that the specimen position adjustment device reaches the preset height from the initial height in the vertical direction under the drive of the lifting mechanism;

[0129] After the specimen position adjusting device reaches a preset height from an initial height in the vertical direction, the clamping mechanism arranged on the lifting mechanism performs a clamping operation on the plastic concrete specimen.

[0130] Below, taking the case where the horizontal moving mechanism, the lifting mechanism, and the clamping translation mechanism are driven by motors, and the clamping mechanism is in a relatively closed initial state as an example, the process of the controller controlling the specimen position adjustment device action mechanism to lift the plastic concrete specimen and move it toward the side with smaller deformation until it moves to the corresponding position is described.

[0131] When the horizontal movement mechanism receives a control command from the controller to perform horizontal movement, a first motor of the horizontal movement mechanism mounted within the base is activated, driving the first slide to translate along a horizontal track mounted within the base, thereby moving the first slide from an initial position away from the center of the base to a desired position closer to the center of the base. During the horizontal movement of the first slide, a first position detection assembly mounted on the horizontal track and / or the base and / or the first slide detects whether the first slide has moved horizontally to the desired position.

[0132] When the position detection assembly for detecting the movement of the first slide detects that the first slide has reached its desired position (i.e., a preset desired position), it sends information about the first slide's movement to the controller. Based on this position detection information, the controller instructs the first motor to stop and the second motor of the lifting mechanism to start. The second motor operates in accordance with this instruction, driving the screw to rotate, thereby driving the telescopic rod upward until it extends out of the base and rises to the desired position. During the vertical upward movement of the telescopic rod, a second position detection assembly located on the base and / or the lifting mechanism detects whether the telescopic rod has reached the desired position.

[0133] When the telescopic rod's raised position detection assembly detects that the telescopic rod has reached its desired position (i.e., raised to the preset desired position), it sends a signal to the controller. Based on this signal, the controller instructs the second motor to stop and the third motor in the clamping mechanism to activate. The third motor operates in response to this signal, rotating the lead screw and opening the clamping assembly's pair of clamping jaws. During this opening process, a third detection assembly, mounted on the clamping jaws and / or the fixed seat and / or the sliding seat, verifies that the jaws have reached their desired position.

[0134] Alternatively, upon receiving information that the telescopic rod has reached its proper position, the controller issues a command to deactivate the second motor and activate the hydraulic cylinder of the gripping mechanism. The hydraulic cylinder operates in response to this command, causing the grippers to open. Similarly, during the gripper opening process, a third position detection component, located on the grippers and / or the fixed base and / or the sliding base, detects whether the grippers have reached the desired position.

[0135] When the in-position detection component for detecting the open position of the clamping assembly of the clamping mechanism detects that it has reached its full opening position, it sends an in-position opening information to the controller. Based on this in-position information, the controller issues an instruction to stop the third motor or hydraulic cylinder and activate the fourth motor of the clamping translation mechanism. The fourth motor operates according to this instruction, driving the screw to rotate, so that the lower translation seat moves from its initial position away from the center of the specimen to a desired position where the pair of clamping claws located above it and open can align with and surround the specimen placed on the lower pressure plate, that is, the pair of clamping claws move toward the specimen until the center of the pair of clamping claws coincides with the center of the specimen. During the process of the lower translation seat driving the pair of clamping claws to translate horizontally, the fourth in-position detection component provided on the lower translation seat and / or the upper connecting base and / or the lower connecting base detects whether the lower translation seat has moved to the desired position.

[0136] When the lower translation seat's position detection assembly detects that the lower translation seat has moved into position, it sends a position detection signal to the controller. Based on this position detection signal, the controller instructs the fourth motor to stop and the third motor or hydraulic cylinder of the clamping mechanism to activate. The third motor or hydraulic cylinder activates in response to this signal, enabling the pair of clamping claws or grippers to securely grip the specimen.

[0137] After the clamping mechanism clamps the specimen, it sends a clamping position information to the controller. Based on the clamping position information and the information that the specimen moves to the required corresponding position, the controller issues an instruction to extend the telescopic rod of the lifting mechanism upward by a predetermined distance. The clamping mechanism will hold the specimen and move it upward so that the bottom of the specimen leaves the lower pressure plate by a preset distance.

[0138] After the specimen is lifted off the lower bearing plate, the lifting mechanism transmits a signal to the controller indicating it has reached its desired position. Based on this signal, along with the direction and distance the specimen has moved to the desired position, the controller instructs the third motor or hydraulic cylinder of the clamping mechanism to stop and the fifth motor of the clamping translation mechanism to activate. The fifth motor operates in response to this signal, driving the upper translation seat longitudinally, thereby moving the specimen to the desired position. The clamping assembly is then controlled to open, releasing the specimen and placing it at the desired position on the lower bearing plate. During this process, the speed of each motor is controlled to determine the distance traveled, and a position sensor detects whether the specimen has reached its desired position.

[0139] After the clamping mechanism moves the specimen to the desired position and releases it, the controller instructs each mechanism to execute the reverse instructions of the above operations, returning them to their initial positions in sequence. During the process of returning to the initial position, each return sensor can detect whether it has returned to its original position.

[0140] After the plastic concrete specimen is picked up and moved to the corresponding position by the action mechanism of the specimen position adjustment device, the pre-stressing operation on the specimen continues, and the difference between the deformation values ​​of two adjacent specimens is compared after the pre-stressing operation. If the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet the predetermined value, the above operation of holding the specimen and moving it to the corresponding position is repeated until the difference between the deformation values ​​of two adjacent plastic concrete specimens meets the predetermined value, and then the pre-stressing operation on the specimen is stopped.

[0141] S03. After the difference between the deformation values ​​of two adjacent plastic concrete specimens meets a predetermined value, the upper bearing plate is driven by a servo motor to perform a formal elastic modulus test on the plastic concrete specimen.

[0142] After the difference between the deformation values ​​of two adjacent plastic concrete specimens meets the predetermined value, the upper bearing plate is driven by a servo motor to conduct a formal elastic modulus test on the plastic concrete specimen according to the specification. The formal elastic modulus test process is carried out according to the specification and will not be detailed here.

[0143] Among them, the servo motor of the present invention can adopt a motor with a force range of 200KN, which can realize the speed control of the moving beam in the test equipment, thereby making the preloading pressure more accurate and the preloading process more controllable.

[0144] During the entire elastic modulus test of a plastic concrete specimen, a pair of optical scale assemblies transmits collected displacement information to a data acquisition device. The data acquisition device receives and processes the displacement information transmitted by the optical scale assemblies and sends it to a controller. The controller receives and processes the information, controls the various operating mechanisms of the device, and displays the relevant results on the computer system's display screen 8, allowing test personnel to obtain real-time displacement and elastic modulus. The computer system pre-stores a test program that automatically controls the various mechanisms to execute corresponding operations. After the test begins, the specimen is compressed and deformed by the upper bearing plate. The pair of optical scale assemblies are compressed by the measuring rod, generating data changes. These data are then transmitted to the computer system via the data acquisition device and automatically retrieved according to the sampling points set in the test program. This fully automates the data retrieval process, eliminating errors caused by human factors. This eliminates human factors and significantly improves the accuracy and efficiency of test retrieval. Furthermore, the difference in specimen deformation after two consecutive preloading cycles can be used to determine whether to automatically move the specimen, significantly improving test efficiency and reducing labor intensity and labor costs.

[0145] Comparative tests revealed that the average maximum deviation rate of force values ​​for a 200kN microcomputer-controlled elastic mold test apparatus using a hydraulic power source to drive the upper bearing plate was 1.1%, while the average maximum deviation rate of force values ​​for a 200kN microcomputer-controlled elastic mold test apparatus using a servo motor as the power source was 0.6%. This indicates that the apparatus using the servo motor as the power source of the present invention provides greater test stability and accuracy than the prior art apparatus using a hydraulic power source.

[0146] Although the present invention has been described in detail above, the present invention is not limited thereto. Those skilled in the art can make modifications based on the principles of the present invention. Therefore, all modifications made in accordance with the principles of the present invention should be understood to fall within the scope of protection of the present invention.

Claims

1. A method for testing the elastic modulus of a plastic concrete specimen, comprising: By performing multiple pre-compression on the plastic concrete specimen, multiple deformation values ​​of the plastic concrete specimen are obtained. When the difference between the deformation values ​​of two adjacent plastic concrete specimens meets a predetermined value, a formal elastic modulus test of the plastic concrete specimen is performed, which is characterized by: The upper bearing plate is driven by a servo motor to achieve multiple preloading of the plastic concrete specimen so as to accurately control the preloading pressure; When the difference between the deformation values ​​of the two adjacent plastic concrete specimens does not meet a predetermined value, the controller receives the difference and controls the actuating mechanism of the specimen position adjustment device supported by the test equipment base according to the difference, so that the actuating mechanism of the specimen position adjustment device picks up the plastic concrete specimen and adjusts the position of the plastic concrete specimen on the lower bearing plate; After the position of the plastic concrete specimen on the lower bearing plate is adjusted, the plastic concrete specimen is pre-pressed until the difference between the deformation values ​​of two adjacent plastic concrete specimens meets a predetermined value; The test piece position adjustment device comprises a horizontal moving mechanism arranged in the test equipment base, a lifting mechanism arranged on the horizontal moving mechanism, and a clamping mechanism arranged on the lifting mechanism. Among them, the controller issues an instruction to control the lifting mechanism to perform a lifting operation based on the information that the clamping mechanism is clamped into position, so that the telescopic rod of the lifting mechanism is extended upward again in the vertical direction; when the in-position sensor of the lifting mechanism detects that the telescopic rod is extended upward into position, it sends an extension into position information to the controller; based on the extension into position information, the controller issues an instruction to control the upper longitudinal translation mechanism of the clamping translation mechanism to perform a longitudinal translation operation, so that the upper longitudinal translation mechanism is longitudinally translated in the horizontal direction; when the in-position sensor of the upper longitudinal translation mechanism detects that it has been translated into position, it sends a translation into position information to the controller; based on the translation into position information of the upper longitudinal translation mechanism, the controller issues an instruction to control the clamping mechanism to perform an opening operation, so that the clamping mechanism opens to move the specimen to the desired position.

2. According to the method according to claim 1, the horizontal moving mechanism is used to move horizontally according to the control instructions issued by the controller; the lifting mechanism is used to perform lifting operations when the horizontal moving mechanism moves into place; and the clamping mechanism is used to perform clamping operations when the lifting mechanism moves into place.

3. The method according to claim 2, wherein the lifting mechanism performs a lifting operation when the horizontal moving mechanism moves into position, comprising: When the in-position sensor arranged in the base detects that the horizontal moving mechanism has moved into position, it sends the in-position information of the horizontal moving mechanism to the controller; The controller issues an instruction to control the lifting mechanism to perform a lifting operation according to the information that the horizontal moving mechanism is in position, so that the lifting mechanism performs the lifting operation.

4. The method according to claim 3, wherein the clamping mechanism performs a clamping operation when the lifting mechanism moves into position, comprising: When the in-position sensor arranged in the base or on the lifting mechanism detects that the lifting mechanism has been lifted to the position, it sends the lifting mechanism in-position information to the controller; The controller issues an instruction to control the clamping mechanism to perform a clamping operation according to the information that the lifting mechanism is in position, so that the clamping mechanism performs the clamping operation.

5. The method according to claim 4, wherein the controller issues an instruction to control the clamping mechanism to perform a clamping operation based on the information that the lifting mechanism is in position, and the clamping mechanism performs the clamping operation, wherein: After receiving the arrival information sent by the lifting mechanism, the controller issues an instruction to control the lower lateral translation mechanism of the holding translation mechanism to perform a lateral translation operation, so that the lower lateral translation mechanism is laterally translated in the horizontal direction; When the in-position sensor of the lower-layer lateral translation mechanism detects that it has been translated into position, it sends translation-in-position information to the controller, and the controller controls the clamping mechanism to perform a clamping operation according to the translation-in-position information.

6. The method according to claim 1, wherein obtaining the deformation value of the plastic concrete specimen by pre-compressing the plastic concrete specimen comprises: When the servo motor drives the upper bearing plate to realize pre-compression of the plastic concrete specimen, a pair of measuring rods on both sides of the upper bearing plate move along with the upper bearing plate; When a pair of measuring rods on both sides of the upper pressure plate moves with the upper pressure plate, a pair of grating scale assemblies on both sides of the lower pressure plate corresponding to the positions of the pair of measuring rods respectively detect the deformation values ​​on both sides of the plastic concrete specimen and transmit the deformation values ​​to the controller.

7. An apparatus for testing the elastic modulus of a plastic concrete specimen using the method according to any one of claims 1 to 6, comprising: A test frame having a base, an upper pressure plate, a lower pressure plate, and an upper pressure plate driving device, characterized in that: The power source of the upper bearing plate driving device is a servo motor capable of accurately controlling the preloading pressure; The base is provided with a specimen position adjustment device, including a specimen position adjustment device action mechanism and a controller. When the plastic concrete specimen is pre-pressed multiple times and the difference between the deformation values ​​of two adjacent plastic concrete specimens does not meet a predetermined value, the controller receives the difference and controls the specimen position adjustment device action mechanism supported by the test equipment base according to the difference, so that the specimen position adjustment device action mechanism picks up the plastic concrete specimen and adjusts the position of the plastic concrete specimen on the lower bearing plate. The test piece position adjustment device comprises a horizontal moving mechanism arranged in the test equipment base, a lifting mechanism arranged on the horizontal moving mechanism, and a clamping mechanism arranged on the lifting mechanism. Among them, the controller issues an instruction to control the lifting mechanism to perform a lifting operation based on the information that the clamping mechanism is clamped into position, so that the telescopic rod of the lifting mechanism is extended upward again in the vertical direction; when the in-position sensor of the lifting mechanism detects that the telescopic rod is extended upward into position, it sends an extension into position information to the controller; based on the extension into position information, the controller issues an instruction to control the upper longitudinal translation mechanism of the clamping translation mechanism to perform a longitudinal translation operation, so that the upper longitudinal translation mechanism is longitudinally translated in the horizontal direction; when the in-position sensor of the upper longitudinal translation mechanism detects that it has been translated into position, it sends a translation into position information to the controller; based on the translation into position information of the upper longitudinal translation mechanism, the controller issues an instruction to control the clamping mechanism to perform an opening operation, so that the clamping mechanism opens to move the specimen to the desired position.

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