Model test flexible cushion net deformation measuring device and measuring method

Abstract

The application discloses a measuring device and method for net deformation of a model test flexible cushion. In operation, the displacement measured from the displacement meter is the net deformation of the flexible cushion. Thus, the net deformation of the flexible cushion can be directly measured, and the data is accurate. The displacement meter is detachably installed on the measured flexible cushion through magnetic attraction of the iron sheet and the magnetic seat. When the measured point position of the flexible cushion is locally uneven due to wrinkles, etc., the magnetic attraction seat is separated from the flexible cushion, and the position of the magnetic attraction seat is slightly adjusted. The placement and inclination of the displacement meter can be slightly adjusted. This is beneficial to reduce the wrinkles at the installation position of the displacement meter, avoids the problem of local unevenness of the flexible cushion after the displacement meter is installed, and further ensures the measurement accuracy of the adjustment of the measured point position.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible cushion layer measurement, and particularly relates to a model test flexible cushion layer net deformation measurement device and a model test flexible cushion layer net deformation measurement method. BACKGROUND

[0002] Flexible cushion layers, such as expanded polystyrene (EPS) and the like, have the advantages of small density, large compression deformation, high strength, and good shock absorption performance, and can be placed in bridge abutments or roadbeds and the like of traffic infrastructure as thermal insulation materials or shock absorption materials. Some scholars have conducted indoor tests and FLAC numerical simulation researches on cantilever retaining walls, and the results show that the earth pressure acting on the lower half of the retaining wall is significantly reduced after the EPS flexible cushion layer is set; the EPS cushion layer set between the retaining wall and the filler can make the rigid retaining wall with small displacement capacity have deformation capacity, so that the soil body is close to the active state from the static state. Some scholars propose to set the EPS cushion layer in the rigid pile foundation retaining wall structure, and the research shows that the wall back earth pressure, the bending moment and the shear force of the anti-slide pile body are all significantly reduced after the flexible cushion layer is set. The EPS and the like have significant thermal insulation and shock absorption effects, but the previous scholars' researches on the flexible cushion layer are limited to theoretical analysis and numerical simulation, and lack of experimental verification of the application of the flexible cushion layer in model tests or actual engineering. Limited by the constraints of real conditions, most scholars adopt model tests to provide reference for the rationality and reliability of theoretical analysis and numerical simulation.

[0003] However, the net deformation of the flexible cushion layer in the model test is difficult to measure. Some scholars measure the deformation of the flexible cushion layer by PIV, but the data obtained in this way are significantly affected by the boundary effect, and the internal deformation cannot be measured. Some scholars fix the displacement meter on the model box, but the deformation obtained by this method includes the displacement of the panel or other rigid structure, and is not the net deformation of the flexible cushion layer. The net deformation of the flexible cushion layer can be obtained by subtracting the displacement of the rigid structure from the total deformation, but the test error of this method is large, and in most cases, especially for high-frequency loading or large-amplitude loading test conditions, the displacement of the rigid structure cannot be accurately measured, so the net deformation of the flexible cushion layer obtained in this way is not accurate. SUMMARY

[0004] Therefore, the present application provides a model test flexible cushion layer net deformation measurement device and a model test flexible cushion layer net deformation measurement method, which can directly and accurately measure the net deformation of the flexible cushion layer.

[0005] In a first aspect, the present application provides a model test flexible cushion layer net deformation measurement device, comprising:

[0006] a displacement meter, configured to penetrate the flexible cushion layer along the thickness direction of the measured flexible cushion layer;

[0007] iron sheet, used to be stacked on the front of the flexible cushion layer;

[0008] magnetic seat, configured to form magnetic attraction with the iron sheet, and used to install the displacement meter;

[0009] spacer, used to be stacked on the back of the flexible cushion layer, the spacer is configured to stop the end of the displacement meter extending to the back;

[0010] Wherein, the direction from the front to the back defines the thickness of the flexible cushion layer.

[0011] Optionally, it also includes a mounting hole opened on the flexible cushion layer, the mounting hole is used to accommodate the displacement meter.

[0012] Optionally, it also includes a PVC pipe, which is used to be embedded in the mounting hole.

[0013] Optionally, the iron sheet is pasted or welded on the front of the flexible cushion layer.

[0014] Optionally, the magnetic seat includes a magnetic attraction head used to magnetically attract the iron sheet and a clamping member fixed to the magnetic attraction head, the clamping member is used to clamp the displacement meter.

[0015] Optionally, the spacer is provided with an elastic card seat, used to accommodate the end of the displacement meter.

[0016] Optionally, the elastic card seat is configured to protrude obviously from the spacer.

[0017] In the second aspect, the application provides a model test flexible cushion layer net deformation measurement method, using the above measurement device.

[0018] The model test flexible cushion layer net deformation measurement device and measurement method provided above, when working, moves with the flexible cushion layer, and the displacement amount read from the displacement meter is the net deformation amount of the flexible cushion layer. Thus, the net deformation amount of the flexible cushion layer can be directly measured, and the data is accurate. The displacement meter is installed on the measured flexible cushion layer in a detachable manner through the magnetic attraction cooperation of the iron sheet and the magnetic seat. When the measured point position of the flexible cushion layer appears local inequality such as wrinkles, only the magnetic attraction seat needs to be separated from the flexible cushion layer and the position of the magnetic attraction seat needs to be fine-tuned, and the placement tilt posture of the displacement meter can be fine-tuned. This is conducive to reducing the wrinkle phenomenon of the installation point of the displacement meter, avoiding the problem of local unevenness of the flexible cushion layer after the displacement meter is placed, and further ensuring the measurement accuracy achieved by adjusting the measured point position. BRIEF DESCRIPTION OF DRAWINGS

[0019] The technical solutions and other beneficial effects of the application will be apparent from the following detailed description of specific embodiments of the application, combined with the accompanying drawings.

[0020] Figure 1 Structure diagram of the device for measuring the example of the present application;

[0021] Figure 2 Structure diagram of the example 1 of the present application;

[0022] Figure 3 Structure diagram of the example 2 of the present application;

[0023] Figure 4 Structure diagram of the example 3 of the present application;

[0024] Figure 5 Structure diagram of the example 4 of the present application.

[0025] In the figure, the elements are identified as follows:

[0026] 1-flexible cushion; 2-PVC pipe; 3-iron sheet; 4-magnetic seat; 41-clamping piece; 5-displacement meter; 6-separator; 7-concrete panel; 8-filler; 9-brick panel; 10-loading plate; 11-actuator. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] In the description of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0029] In the description of the present application, it should be noted that unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplifying the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not in itself indicate a relationship between the various embodiments and / or settings being discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0031] Reference Figures 1-5 The present application provides a device for measuring the net deformation of a model test flexible cushion 1, comprising:

[0032] A displacement meter 5 is used to penetrate the flexible cushion 1 along the thickness direction of the measured flexible cushion 1;

[0033] An iron sheet 3 is used to be stacked on the front surface of the flexible cushion 1;

[0034] A magnetic base 4 is configured to form a magnetic attraction with the iron sheet 3 and is used to install the displacement meter 5;

[0035] A spacer 6 is used to be stacked on the back surface of the flexible cushion 1, and the spacer 6 is configured to stop the end of the displacement meter 5 extending towards the back surface;

[0036] Wherein, the direction from the front surface to the back surface is defined as the thickness of the flexible cushion 1.

[0037] The magnetic attraction of the above-mentioned iron sheet 3 and magnetic base 4 can directly realize the detachable installation of the displacement meter 5 on the measured flexible cushion 1. The specific design considerations or actual application scenarios of the detachable installation are as follows:

[0038] Since the displacement meter 5 penetrates the flexible cushion 1 along the thickness direction of the measured flexible cushion 1, there is a pulling force in the thickness direction of the flexible cushion 1 exerted by the displacement meter 5 during the penetration of the displacement meter 5 in the thickness direction (i.e. during the insertion of the displacement meter 5 into the flexible cushion 1) and after the end of the displacement meter 5 extending towards the back surface is stopped by the spacer 6. The "flexibility" of the flexible cushion 1 can easily cause local wrinkles and other uneven phenomena near the insertion site of the displacement meter 5 due to the pulling force. Local wrinkles not only cause the displacement meter 5 and the flexible cushion 1 to not completely adhere, but worse, the deformation of the flexible cushion 1 is absorbed by the wrinkles, thereby causing the deformation collected by the displacement meter 5 to not reflect the true deformation.

[0039] The inventor of the present application has found a solution to the above-mentioned technical problem. According to the conventional thinking, in order to eliminate the wrinkles of the flexible mat 1 in the area near the insertion site of the displacement meter 5, the most direct means is to set a sheet-like piece similar to the spacer 6 at the insertion site of the displacement meter 5 (i.e. the front position of the flexible mat 1). Although the sheet-like piece can directly act on the wrinkles, it has been overlooked that the extrusion caused by the sheet-like piece being attached to the flexible mat 1 cannot avoid lateral extrusion (lateral refers to the direction other than the thickness direction of the flexible mat 1), the direction of the lateral extrusion is difficult to control, and only part of the wrinkles can be removed, and sometimes it may cause the wrinkles to be intensified. Therefore, the effect of the sheet-like piece on the elimination of wrinkles is very limited.

[0040] The inventor of the present application has found a solution to the above-mentioned technical problem. According to the conventional thinking, in order to eliminate the wrinkles of the flexible mat 1 in the area near the insertion site of the displacement meter 5, the most direct means is to set a sheet-like piece similar to the spacer 6 at the insertion site of the displacement meter 5 (i.e. the front position of the flexible mat 1). Although the sheet-like piece can directly act on the wrinkles, it has been overlooked that the extrusion caused by the sheet-like piece being attached to the flexible mat 1 cannot avoid lateral extrusion (lateral refers to the direction other than the thickness direction of the flexible mat 1), the direction of the lateral extrusion is difficult to control, and only part of the wrinkles can be removed, and sometimes it may cause the wrinkles to be intensified. Therefore, the effect of the sheet-like piece on the elimination of wrinkles is very limited.

[0041] Secondly, when the displacement meter 5 is tilted left and right around the thickness direction of the flexible mat 1, the magnetic base 4 will be separated from the flexible mat 1, and at this moment, the "constraint" of the wrinkles will be suddenly released, which is the most favorable aspect for the elimination of wrinkles. Through the above two aspects, the wrinkles in the area near the insertion site of the displacement meter 5 can be effectively eliminated.

[0042] It should be understood that the flexible mat 1 can be placed alone, or placed on the outer surface of other test materials or as a interlayer in other test materials.

[0043] It should be understood that the flexible mat 1 can be placed alone, or placed on the outer surface of other test materials or as a interlayer in other test materials.

[0044] In some examples, a PVC pipe 2 is further included, which is used to be embedded in the mounting hole.

[0045] Through the PVC pipe 2, the mounting hole can be supported to avoid significant deformation of the mounting hole, which causes the displacement meter 5 to sway left and right around the thickness direction of the flexible mat 1, resulting in the displacement meter 5 being not firmly fixed.

[0046] As a specific example, the magnetic seat 4 includes a magnetic head for magnetic attraction to the iron sheet 3 and a clamping member 41 for fixing the magnetic head, which is used to clamp the displacement meter 5.

[0047] In this way, by clamping the displacement meter 5 by the clamping member 41, the separation or combination operation of the magnetic seat 4 and the iron sheet 3 is facilitated.

[0048] It should be understood that the iron sheet 3 can be a piece or multiple pieces arranged intermittently. In the implementation of a piece, the iron sheet 3 covers most or substantially all of the surface of the flexible cushion layer 1. In the implementation of multiple pieces, the coverage area of the iron sheet 3 is selected according to the opening area of the mounting hole. It should be understood that the coverage area of the patch leaves a part of space for fine adjustment of the position of the magnetic seat 4.

[0049] As a specific example, the iron sheet 3 is pasted or welded on the front surface of the flexible cushion layer 1.

[0050] In some examples, the spacer 6 is provided with an elastic seat (not shown in the figure) for accommodating the end of the displacement meter 5.

[0051] In this way, by accommodating the end of the displacement meter 5 by the elastic seat, the end of the displacement meter 5 can be fixed conveniently after the displacement meter 5 is inserted into the mounting hole, thereby avoiding the displacement meter 5 from being frequently touched due to other non-removable fixing methods.

[0052] In some examples, the elastic seat is configured to protrude obviously from the spacer 6 (not shown in the figure).

[0053] In this way, by the protruding arrangement of the spacer 6, the elastic seat can be inserted into the mounting hole or the PVC pipe 2 after the end of the displacement meter 5 is clamped by the elastic seat, which ensures the consistency of the fixing direction of the end of the displacement meter 5 by the elastic seat and the fixing direction of the other end of the displacement meter 5, and reduces the possibility of loosening of the displacement meter 5 during use.

[0054] The specific operation process of the test method is described below in relation to several actual application scenarios.

[0055] The specific installation and implementation process of Example Structure 1 is as follows:

[0056] (1) In this example, the flexible cushion layer 1 adopts an EPS expanded polystyrene foam block with a size of 30 cm x 5 cm x 100 cm (length x width x height), and the EPS expanded polystyrene foam block is placed vertically. According to the test requirements, the required measuring points are determined to be a vertical column in the middle of the EPS block, and mounting holes are opened on the EPS block near the measuring points by using an electric melting gun, with a hole diameter less than or equal to 25 mm.

[0057] (2) Embed PVC pipe 2 in the installation hole, the outer diameter of PVC pipe 2 is 25 mm, the wall thickness is 2 mm, and the inner diameter of the installation hole is 21 mm;

[0058] (3) Stick a circular thin plastic spacer 6 with a diameter of 3 cm on the back of the EPS block at the position of the installation hole;

[0059] (4) Stick an iron sheet 3 with a size of 100 cm x 3 cm (length x width) on the surface of the EPS block;

[0060] (5) Use the magnetic seat 4 as a fixed support and magnetically connect it to the iron sheet 3 to fix it on the surface of the flexible cushion layer 1;

[0061] (6) Fix the displacement meter 5 on the clamping piece 41 of the magnetic seat, adjust the position of the displacement meter 5 to make it pass through the pre-set installation hole of the EPS block in parallel, the probe length of the displacement meter 5 used in this example is 5 cm, the pre-set compression amount of the probe tip is 3 cm when it presses against the spacer 6, and then the displacement meter 5 is adjusted to zero;

[0062] (7) Repeat the steps in (6);

[0063] (8) Collect test data.

[0064] The specific installation implementation process of Example Structure 2 is as follows:

[0065] (1) In this example, the flexible cushion layer 1 uses EPS expanded polystyrene foam blocks, which are placed as an interlayer between the concrete panel 7 and the filler 8, with a size of 30 cm x 5 cm x 100 cm (length x width x height), and the EPS expanded polystyrene foam blocks are placed vertically. According to the test requirements, the required measuring points are determined to be a vertical column in the middle of the EPS block, and installation holes are opened on the EPS block near the measuring points using an electric melting gun, with a hole diameter less than or equal to 25 mm;

[0066] (2) Embed PVC pipe 2 in the installation hole, the outer diameter of PVC pipe 2 is 25 mm, the wall thickness is 2 mm, and the inner diameter of the installation hole is 21 mm;

[0067] (3) Place PVC pipe 2 in the hole position during the pouring of the concrete panel 7, and wait for the strength to reach the target value after curing;

[0068] (4) Stick the EPS block and the concrete panel 7 together, aligning the pre-set installation hole;

[0069] (5) Stick a circular thin plastic spacer 6 with a diameter of 3 cm on the back of the EPS block at the position of the installation hole;

[0070] (6) Stick an iron sheet 3 with a size of 100 cm x 3 cm (length x width) on the surface of the concrete panel 7;

[0071] (7) The magnetic seat 4 is used as a fixing support, and is fixed on the surface of the concrete panel 7 through magnetic connection on the iron sheet 3;

[0072] (8) The displacement meter 5 is fixed on the clamping part 41 of the magnetic seat 4, and the position of the displacement meter 5 is adjusted so as to be parallel to the pre-set installation hole of the concrete panel 7 and the EPS block, the probe length of the displacement meter 5 in this example is 5 cm, the pre-set compression amount of the probe end when pressing against the partition sheet 6 is 3 cm, and then the displacement meter 5 is adjusted to zero;

[0073] (9) The step in (8) is repeated;

[0074] (10) The test data is collected.

[0075] The specific installation implementation process of the example structure 3 is as follows:

[0076] (1) In this example, the flexible cushion layer 1 is an EPS expanded polystyrene foam block, which is placed as an interlayer between the brick panel 9 and the filler 8, and the size is 30 cm x 5 cm x 100 cm (length x width x height), the EPS expanded polystyrene foam block is placed vertically, and according to the test requirements, the required measuring point is determined as a vertical column in the middle of the EPS block, and an installation hole is formed on the EPS block near the measuring point by using an electric melting gun, and the hole diameter is less than or equal to 25 mm;

[0077] (2) The PVC pipe 2 is embedded in the installation hole, the outer diameter of the PVC pipe 2 is 25 mm, the wall thickness is 2 mm, and the inner diameter of the installation hole is 21 mm;

[0078] (3) The hole is formed in advance when the brick panel 9 is built;

[0079] (4) The EPS block and the brick panel 9 are adhered together, and the pre-set installation hole is aligned;

[0080] (5) On the back of the EPS block, a circular thin plastic partition sheet 6 with a diameter of 3 cm is adhered at the position of the installation hole;

[0081] (6) The iron sheet 3 is adhered on the surface of the brick panel 9;

[0082] (7) The magnetic seat 4 is used as a fixing support, and is fixed on the surface of the brick panel 9 through magnetic connection on the iron sheet 3;

[0083] (8) The displacement meter 5 is fixed on the clamping part 41 of the magnetic seat 4, and the position of the displacement meter 5 is adjusted so as to be parallel to the pre-set installation hole of the brick panel 9 and the EPS block, the probe length of the displacement meter 5 in this example is 5 cm, the pre-set compression amount of the probe end when pressing against the partition sheet 6 is 3 cm, and then the displacement meter 5 is adjusted to zero;

[0084] (9) The step in (8) is repeated;

[0085] (10) Perform test data collection.

[0086] Example structure 4 specific installation implementation process:

[0087] (1) In this example, the flexible cushion layer 1 uses EPS expanded polystyrene foam blocks, which are placed as an interlayer between the loading plate 10 and the filler 8. The EPS expanded polystyrene foam blocks are placed horizontally. According to the test requirements, determine the required measurement point position around the loading plate 10. Near the measurement point, use an electric melting gun to open an installation hole on the EPS block, with a hole diameter less than or equal to 25mm;

[0088] (2) Embed the PVC pipe 2 in the hole, with an outer diameter of 25mm, a wall thickness of 2mm, and an installation hole diameter of 21mm;

[0089] (3) On the back of the EPS block, paste a circular thin plastic spacer 6 with a diameter of 3cm at the installation hole position;

[0090] (4) Apply adhesive to the surface of the EPS block and stick an iron sheet 3. If the loading plate 10 is an iron plate, this step can be omitted;

[0091] (5) Install the loading plate 10;

[0092] (6) Connect the actuator 11 and the loading plate 10, install the actuator 11, and align the actuator 11 with the model center position and the measurement point position;

[0093] (7) Use the magnetic seat 4 as a fixed support, which is magnetically connected to the iron sheet 3 and fixed to the upper surface of the loading plate 10. If the loading plate 10 is an iron plate, the magnetic seat is installed on the loading plate;

[0094] (8) Fix the displacement meter 5 to the clamping piece 41 of the magnetic seat 4, adjust the position of the displacement meter 5 so that it passes vertically through the pre-set installation hole of the EPS block. In this example, the probe length of the displacement meter 5 is 5cm, and the pre-set probe end is pressed against the spacer 6 with a compression of 3cm. Then, adjust the displacement meter 5 to zero;

[0095] (9) Repeat the steps in (8);

[0096] (10) Perform test data collection.

[0097] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any changes or replacements within the technical scope disclosed in the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application.

Claims

1. A device for measuring the net deformation of a flexible pad in a model test, characterized in that, include: A displacement gauge is used to penetrate the flexible pad along the thickness direction of the flexible pad being measured. Iron sheets are used to be stacked on the front side of the flexible padding layer; A magnetic base is configured to magnetically attract the iron sheet and is used to mount the displacement gauge. A spacer is used to be stacked on the back side of the flexible pad, the spacer being configured to stop the end of the displacement gauge extending to the back side; The thickness of the flexible pad layer is defined as the direction from the front to the back. The magnetic base is configured to be detached and repositioned via magnetic connection, and the tilt of the displacement gauge relative to the flexible pad is finely adjusted to reduce wrinkles in the flexible pad at the displacement gauge mounting position.

2. The measuring device according to claim 1, characterized in that, It also includes mounting holes formed in the flexible padding layer for accommodating the displacement gauge.

3. The measuring device according to claim 2, characterized in that, It also includes a PVC pipe, which is used to be embedded in the mounting hole.

4. The measuring device according to claim 1, characterized in that, The iron sheet is glued or welded to the front of the flexible pad.

5. The measuring device according to claim 1, characterized in that, The magnetic base includes a magnetic head for magnetically attracting the iron sheet and a clamping member for fixing the magnetic head, the clamping member being used to clamp the displacement gauge.

6. The measuring device according to claim 1, characterized in that, The spacer is provided with an elastic retainer for accommodating the end of the displacement gauge.

7. The measuring device according to claim 6, characterized in that, The resilient card holder is configured to protrude significantly from the spacer.

8. A method for measuring the net deformation of a flexible pad in a model test, characterized in that, The measuring device as described in claim 1 is used.

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