Indirect tensile fatigue test clamp

Abstract

The utility model discloses an indirect tensile fatigue test clamp. The indirect tensile fatigue test fixture comprises a base for supporting and placing a to-be-tested piece; a guide post is arranged on the base; the measuring table is sleeved on the guide column and moves up and down along the guide column; an opening penetrating up and down is formed in the measuring table, limiting guide rails are arranged on two opposite sides in the opening, and a displacement sensor adjusting structure is arranged on the measuring table above the opening; the pressing block is arranged on the guide column in a sleeving manner, and the pressing block is driven by external force to downwards apply pressure to the to-be-tested piece along the guide column; in the testing process, the displacement sensor adjusting structure makes contact with the to-be-tested piece in the direction perpendicular to the pressure of the pressing block and senses the displacement change of the to-be-tested piece in the direction. The indirect tensile fatigue test clamp has the functions of displacement sensor fixing and test piece guiding, the problems that a traditional displacement sensor fixed to a test piece is tedious in operation and inaccurate in data acquisition are solved, and the test piece can be conveniently guided to be damaged in the loading process.

Description

TECHNICAL FIELD

[0001] The utility model relates to an indirect tensile fatigue test fixture. BACKGROUND

[0002] The indirect tensile fatigue test is the test method for testing the fatigue resistance of asphalt mixture by applying force to the side of the test piece, measuring the force value and the deformation in each direction, and calculating the fatigue resistance of the asphalt mixture. The test method is simple, basically meets the requirements of fatigue design analysis of asphalt pavement, has certain correlation with the actual pavement performance, can evaluate the fatigue performance of the pavement core sample, and has other advantages. It is a commonly used test method for evaluating the fatigue resistance of asphalt mixture, and is widely used in the performance research of asphalt mixture. However, there are some problems in the actual test operation, such as the test piece falling off or deviating during the pressure application process, and the inconvenient operation when installing the displacement sensor, which often leads to inaccurate data collection due to improper installation of the sensor.

[0003] Therefore, the improved indirect tensile fatigue test fixture is provided.

[0004] It should be noted that the above content belongs to the technical cognition of the inventor and does not necessarily constitute the prior art. UTILITY MODEL CONTENT

[0005] In order to solve the above problems, the utility model provides an indirect tensile fatigue test fixture which has displacement sensor fixing and test piece guiding functions, improves the problem of complicated operation and inaccurate data collection of the displacement sensor fixed on the test piece, is convenient for guiding the test piece to break down during the loading process, is suitable for test pieces of different sizes, and solves the problems in the prior art.

[0006] The utility model provides the following technical scheme:

[0007] An indirect tensile fatigue test fixture comprises:

[0008] A base is used to support and place a test piece; a guide column is arranged on the base;

[0009] A measuring table is sleeved on the guide column and moves up and down along the guide column to adjust the vertical distance from the base; an opening is arranged on the measuring table and extends upward and downward; limit guide rails are arranged on two opposite sides in the opening; and a displacement sensor adjusting structure is arranged on the measuring table above the opening;

[0010] A pressing block is sleeved on the guide column, and the pressing block is driven by external force to apply pressure to the test piece downward along the guide column;

[0011] During the test, the displacement sensor adjusting structure contacts the test piece in a direction perpendicular to the pressure of the pressing block and senses the change in displacement of the test piece in the direction.

[0012] Further, the displacement sensor adjusting structure comprises two parallel and spaced pneumatic displacement sensors, and a displacement sensor clamping strip is arranged at the end of each pneumatic displacement sensor; a limiting seat corresponding to the displacement sensor clamping strip is arranged on the measuring table, a displacement sensor adjusting rod is movably sleeved in the limiting seat, and a spring is connected between each displacement sensor adjusting rod and the displacement sensor clamping strip close to the displacement sensor adjusting rod.

[0013] Further, the spring is a return spring.

[0014] Further, the pneumatic displacement sensor is an LVDT pen-type displacement sensor; the end of the pneumatic displacement sensor is fixedly connected or clamped to the inner side of the displacement sensor clamping strip.

[0015] Further, the structure of the clamping fixation can be that a slot hole is arranged on the inner side surface of one of the displacement sensor clamping strips, the slot hole is matched with the measuring rod measuring head of the pneumatic displacement sensor, the end of the pneumatic displacement sensor is fixedly connected to the inner side of the other displacement sensor clamping strip through the cooperation of the measuring head and the slot hole, and thus the pressure generated by the test piece under pressure acts on the displacement sensor clamping strips at both ends of the test piece, so that the displacement sensor clamping strips drive the measuring rod of the pneumatic displacement sensor to move, the movement of the measuring rod drives the movement of the iron core in the pneumatic displacement sensor, the displacement of the iron core is converted into a voltage signal output, and the amplitude value at this moment is collected to obtain the movement distance of the measuring head. The principle is the general working principle of the existing pneumatic displacement sensor.

[0016] Further, a displacement sensor transmission line is arranged at one end of the pneumatic displacement sensor, and the displacement sensor transmission line is used for transmitting the above-mentioned change signal to an external data receiving end.

[0017] Further, the limiting guide rail comprises a limiting plate, a guide rail bolt is arranged on the measuring table, and the guide rail bolt is used for adjusting the horizontal distance between the two limiting plates and fixing the limiting plates.

[0018] Further, a fixing bolt is arranged on the measuring table, the fixing bolt abuts against the side wall of the guide column, and the pressing block is in clearance fit with the guide column.

[0019] Further, a fixing bolt can also be arranged on the pressing block, so as to ensure the stability of the pressing block arranged on the guide column when the pressing block is not in use. Alternatively, according to the actual test requirement, the pressing block is arranged outside, and when the pressure test is needed, the pressing block is sleeved on the guide rod, and the pressing block is adjusted to gradually contact the test piece downward. Then the pressing block is continuously driven by the pressing machine to apply force to the test piece.

[0020] Further, the to-be-tested piece is a cylindrical to-be-tested piece; a lower pressing horizontal strip is arranged on the base, and an upper pressing horizontal strip is arranged on the bottom surface of the pressing block corresponding to the lower pressing horizontal strip, and the bottom surface of the upper pressing horizontal strip and the top surface of the lower pressing horizontal strip are both circular arc surfaces matched with the side wall of the cylindrical to-be-tested piece.

[0021] Further, the cylindrical side surface of the cylindrical to-be-tested piece is matched with the lower pressing horizontal strip arranged on the base; when the pressing block is pressed and contacts the cylindrical test piece, the cylindrical top surface is matched with the circular arc surface on the upper pressing horizontal strip arranged on the pressing block.

[0022] Further, the circular arc surface is a circular arc concave surface penetrating along the length direction of the upper pressing horizontal strip or the lower pressing horizontal strip.

[0023] Further, the width of the displacement sensor adjusting structure is greater than the length between the two planes of the cylindrical to-be-tested piece; and the length of the displacement sensor adjusting structure in the non-working state is not greater than the diameter of the cylindrical to-be-tested piece.

[0024] Further, in the non-working state of the pneumatic displacement sensor, the distance between the two displacement sensor clamping strips is not greater than the diameter of the cylindrical to-be-tested piece. In this way, the displacement sensor clamping strip can better fit the side surface of the cylindrical to-be-tested piece during the entire test process, and the pneumatic displacement sensor can be fixed on the outside of the cylindrical to-be-tested piece, so that the two pneumatic displacement sensors can better sense the deformation of the cylindrical to-be-tested piece when the cylindrical to-be-tested piece is deformed under pressure.

[0025] Further, the indirect tensile fatigue test clamp can also be used for testing a square to-be-tested piece. Similarly, the width of the displacement sensor adjusting structure is greater than the width of the square to-be-tested piece, and the distance between the two displacement sensor clamping strips is not greater than the length of the square to-be-tested piece.

[0026] The indirect tensile fatigue test clamp provided in the present application can bring the following beneficial effects:

[0027] 1、The measuring table of the indirect tensile fatigue test clamp of the present application is adjustable up and down, can be suitable for cylindrical to-be-tested pieces of different diameters, and is more convenient, flexible and multi-purpose to use. The limiting guide rail arranged on the measuring table has a function of guiding the destruction of the to-be-tested piece, prevents the position of the to-be-tested piece from being greatly changed during the loading process, avoids the influence of the destruction form on the accuracy of data, and the limiting guide rail does not exert active stress on the to-be-tested piece, and has no influence on the test result; at the same time, the limiting guide rail also ensures the stability of the to-be-tested piece placed on the base during the test process.

[0028] 2, The displacement sensor installed on the measuring table of the test fixture is convenient and fast to install, and the collected data is guaranteed to be the data between the two surfaces of the test piece during the test. The displacement sensor is fixed through the displacement sensor clamping strip, the stability of the displacement sensor during the experiment is guaranteed, the inaccurate interference to the collected data is reduced, and the problems of complicated operation of fixing the displacement sensor to the test piece and inaccurate data collection are avoided.

[0029] The structure improvement of the above displacement sensor fixing and test piece guiding functions is integrated, which preferably avoids the influence of other factors during the test, is flexible to adjust, is more practical, the collected data is more accurate, and the test result is more practical. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application. In the drawings:

[0031] Figure 1 It is a structural schematic view of the present application.

[0032] Among them, 1 base, 2 measuring table, 3 pressing block, 4 guide column, 5 fixing bolt, 6 opening, 7 limit guide rail, 8 guide rail bolt, 9 pneumatic displacement sensor, 10 displacement sensor clamping strip, 11 limit seat, 12 displacement sensor adjusting rod, 13 spring, 14 displacement sensor transmission line, 15 lower pressing cross strip, 16 upper pressing cross strip. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the overall concept of the present application, the following will be described in detail with reference to the drawings.

[0034] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application.

[0035] As Figure 1As shown in the embodiment, the indirect tensile fatigue test fixture structure is disclosed, specifically, the test fixture comprises a base 1, a measuring table 2 and a pressing block 3 arranged in sequence from bottom to top, two guide columns 4 are symmetrically arranged on the base, the measuring table 2 and the pressing block 3 are connected with the guide columns 4 in a sleeved manner, a fixing bolt 5 is arranged on the measuring table 2, and the measuring table is fixed after being adjusted to a suitable position along the guide column. The pressing block is in clearance fit with the guide column, and when pressure is applied from the top, the pressing block moves downward along the guide column 4 and contacts the test piece to apply force to the test piece.

[0036] An opening 6 penetrating from top to bottom is arranged on the measuring table 2 inside the guide column 4, a limiting guide rail 7 is arranged on each of the left and right opposite sides of the opening, and the limiting guide rail is adjusted and fixed to the measuring table through a guide rail bolt 8. A displacement sensor adjusting structure is arranged between the front and rear parts of the measuring table above the opening. The displacement sensor adjusting structure comprises two pneumatic displacement sensors 9 arranged horizontally and in parallel, a displacement sensor clamping strip 10 is arranged at the front and rear ends of the two pneumatic displacement sensors, respectively, a limiting seat 11 is arranged on the measuring table 2 corresponding to the displacement sensor clamping strip 10, a displacement sensor adjusting rod 12 is movably sleeved in the limiting seat, and a spring 13 is connected between each displacement sensor adjusting rod 12 and the displacement sensor clamping strip 10 close to it.

[0037] The end of the pneumatic displacement sensor 9 is fixedly connected to the inside of the displacement sensor clamping strip 10. A displacement sensor transmission line 14 is arranged at the rear end of the pneumatic displacement sensor, and the displacement sensor transmission line is used to transmit the sensing change signal of the displacement sensor to an external data receiving end.

[0038] As an embodiment, the connection between the pneumatic displacement sensor and the displacement sensor clamping strip in the test fixture can also adopt a clamping fixed connection structure. For example, a slot hole can be arranged on the inner side surface of the front displacement sensor clamping strip 10, the slot hole is matched with the front end probe of the measuring rod of the pneumatic displacement sensor, the front end of the pneumatic displacement sensor is matched with the slot hole through the probe to realize clamping and fixing with the displacement sensor clamping strip 10, and the rear end of the pneumatic displacement sensor is directly fixed to the inside of the rear displacement sensor clamping strip 10.

[0039] The limiting guide rail 7 is a limiting plate, and the guide rail bolt 8 arranged on the measuring table 2 is used to adjust the horizontal distance between the two limiting plates and fix the limiting plates.

[0040] A lower pressing horizontal strip 15 is arranged in the middle of the top surface of the base 1, and an upper pressing horizontal strip 16 is arranged in the middle of the bottom surface of the pressing block 3 corresponding to the lower pressing horizontal strip. The bottom surface of the upper pressing horizontal strip and the top surface of the lower pressing horizontal strip are both circular arc surfaces, and the circular arc surfaces are arc-shaped concave surfaces penetrating along the length direction of the upper pressing horizontal strip or the lower pressing horizontal strip.

[0041] The test fixture is used for indirectly tensile fatigue test of the cylindrical test piece, and the cylindrical test piece is placed with the arc side as the support surface during the test. The horizontal distance of the pneumatic displacement sensor is greater than the length between the left and right planes (understood as the two bottom surfaces of the cylinder) of the cylindrical test piece, that is, the cylindrical test piece is ensured not to contact the pneumatic displacement sensor during the test; the two displacement sensor clamping strips are in abutting contact with the front and rear sides of the diameter position of the cylindrical test piece before the test and during the whole test process.

[0042] In use, first, the cylindrical test piece processed to a specified size is placed on the lower pressing cross strip 14, the circular side of the test piece is in contact with the arc-shaped concave surface of the top surface of the lower pressing cross strip 15, the height of the measuring table 2 is adjusted according to the size of the test piece, is adjusted to a suitable height, the measuring table is lowered to the test piece to enter the pneumatic displacement sensor 9 through the opening 6, and the inner side of the displacement sensor clamping strip 10 is attached to the front and rear sides of the diameter position of the test piece, the fixing bolt 5 is tightened, and the measuring table 2 is fixed on the guide column 4; during the adjustment process, when the diameter of the cylindrical test piece is slightly greater than the distance between the two displacement sensor clamping strips 10, the front end probe of the pneumatic displacement sensor is stretched by manually pulling the displacement sensor adjusting rod 12, so that the distance between the front and rear of the two displacement sensor clamping strips is increased to be suitable for the middle part (the front and rear sides of the diameter) of the cylindrical test piece, then the inner side of the displacement sensor clamping strip 10 is in abutting contact with the front and rear sides of the diameter of the cylindrical test piece under the elastic recovery of the spring 13, and the inner side of the displacement sensor clamping strip 10 is in abutting contact with the front and rear sides of the diameter of the cylindrical test piece during the whole test process. The pneumatic displacement sensor 9 is fixed on the left and right sides of the cylindrical test piece. Then, the guide rail bolt 8 is adjusted, the inner sides of the two limiting guide rails 7 are attached to the left and right planes of the cylindrical test piece respectively without pressure, and the adjustment of the guide rail bolt 8 is stopped. The pressing block 12 is adjusted downward along the guide column 2 until the lower surface of the upper pressing cross strip 16 contacts the upper surface of the cylindrical test piece, and then the press machine applies a load on the upper surface of the pressing block 3 to start the test, and the deformation amount of the cylindrical test piece is transmitted to the receiver through the displacement sensor transmission line 14 of the pneumatic displacement sensor 10. Since the front and rear sides of the cylindrical test piece are in contact with the displacement sensor clamping strip 9 and the left and right sides are in contact with the limiting guide rail 7, the setting structure has the function of guiding the test piece to break, so that the cylindrical test piece can better extend and break in the front and rear directions when gradually subjected to downward pressure, thereby avoiding large changes in position and eliminating the influence of the breaking form on the accuracy of the data as much as possible.

[0043] The above only describes the embodiments of the present application and is not used to limit the present application. The present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the scope of claims of the present application.

[0044] The parts not described in the utility model are the known technology of those skilled in the art.

Claims

1. An indirect tensile fatigue test fixture characterized by, The utility model relates to a kind of test device for testing the vertical compression performance of test piece, including: Base, the base is used to support the piece to be tested to be placed;Guide column is arranged on base; Measuring table, the measuring table is sleeved on guide column and moves up and down along guide column to adjust vertical spacing with base;Upper and lower through-opening is arranged on measuring table, limiting guide rail is arranged in two opposite sides in through-opening, displacement sensor adjusting structure is arranged on the measuring table above through-opening; Compression block, the compression block is sleeved on guide column, and compression block is driven to press test piece downward along guide column by external force; The displacement sensor adjusting structure contacts test piece in the direction perpendicular to the pressure of compression block during testing and senses the displacement change of test piece in the direction.

2. The indirect tensile fatigue test clamp of claim 1, wherein, The displacement sensor adjusting structure includes two pneumatic displacement sensors arranged in parallel and spaced apart, and a displacement sensor clamping strip is arranged at the end of each pneumatic displacement sensor;Limiting seat is arranged on the measuring table corresponding to the displacement sensor clamping strip, displacement sensor adjusting rod is movably sleeved in the limiting seat, and spring is connected between each displacement sensor adjusting rod and the displacement sensor clamping strip close to it.

3. The indirect tensile fatigue test fixture of claim 2, wherein, The pneumatic displacement sensor is an LVDT pen-type displacement sensor;The end of the pneumatic displacement sensor is fixedly connected or clamped with the inner side of the displacement sensor clamping strip.

4. The indirect tensile fatigue test fixture of claim 1, wherein, The limiting guide rail includes limiting plate, guide rail bolt is arranged on the measuring table, and the guide rail bolt adjusts the horizontal spacing of the two limiting plates and is used for fixing each limiting plate.

5. The indirect tensile fatigue test fixture of claim 1, wherein, Fixed bolt is arranged on the measuring table, and the fixed bolt abuts against the side wall of guide column;Compression block is gap-fitted with guide column.

6. The indirect tensile fatigue test fixture of claim 1, wherein, The test piece is a cylindrical test piece;Lower pressing crosspiece is arranged on base, and upper pressing crosspiece is arranged on the bottom surface of compression block corresponding to the lower pressing crosspiece;The bottom surface of the upper pressing crosspiece and the top surface of the lower pressing crosspiece are both circular arc surfaces matched with the side wall of the cylindrical test piece.

7. The indirect tensile fatigue test clamp of claim 6, wherein, The circular arc surface is a circular arc concave surface penetrating along the length direction of the upper pressing crosspiece or the lower pressing crosspiece.

8. The indirect tensile fatigue test fixture of claim 6, wherein, The width of the displacement sensor adjusting structure is greater than the length between the two planes of the cylindrical test piece;The length of the displacement sensor adjusting structure in non-working state is not greater than the diameter of the cylindrical test piece.

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