A multi-functional small punch specimen testing apparatus and method

Abstract

The present application relates to a kind of multifunctional small punch experimental device and method, comprising: drive unit, loading unit, first fixed unit, second fixed unit, third fixed unit, detection unit, temperature control unit and control unit;Drive unit moves according to drive signal and drives loading unit;First fixed unit fixes loading unit, and second fixed unit and third fixed unit cooperate and fix circular sample;Detection unit carries out force displacement detection to sample to be applied;To be applied sample includes: multiple punch ball;Temperature control unit executes temperature adjustment control according to the control signal output by control unit.This application can determine the mechanical property parameter of material based on multiple groups of data in single test, and has high reliability;It can also solve the problem that existing fixture test temperature is single, and also can realize single experiment to obtain the mechanical property parameter of multiple materials at specific temperature, avoid repeated test, significantly improve experimental efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical property testing of metal materials, and more particularly to a multifunctional small punch test device and method. Background Art

[0002] With the continuous increase in energy demand, the service integrity and safety of equipment such as oil and gas pipelines and pressure vessels, as critical energy mechanical structures, are becoming increasingly important. These devices are exposed to long-term service in high-pressure, high-temperature, deep-sea cryogenic, and corrosive environments, and deterioration of their mechanical properties is unavoidable. Therefore, mechanical properties in high and low-temperature environments are a key indicator for evaluating the safety of critical equipment structures. Accurate testing and assessment of the degradation of mechanical properties of materials under different temperature environments is essential.

[0003] The current experimental device of the small punch has the following defects:

[0004] 1. After obtaining the load-displacement curve of the material through a single experiment, the existing small punch device generally extracts the value of a specific point on the curve and determines the material mechanical performance parameters according to an empirical formula. This has relatively low reliability and a relatively limited scope of application of the empirical formula, which restricts the application scope of the small punch test device.

[0005] 2. When testing the mechanical properties of a specific material under different temperature conditions, the existing small punch device requires repeated tests, which is relatively inefficient.

[0006] 3. When testing the mechanical properties of different materials under the same temperature conditions, the existing small punch device also requires multiple repeated tests, which affects the experimental efficiency. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a multifunctional small punch experimental device and method in response to the problems existing in the prior art.

[0008] The technical solution adopted by the present invention to solve the technical problem is: constructing a multifunctional small punch experimental device, including: a driving unit, a loading unit, a first fixing unit, a second fixing unit, a third fixing unit, a detection unit, a temperature control unit and a control unit;

[0009] The driving unit is connected to the loading unit and is used to drive the loading unit to move according to a driving signal;

[0010] The first fixing unit, the second fixing unit and the third fixing unit are arranged axially from top to bottom, the first fixing unit is used to fix the loading unit, and the second fixing unit and the third fixing unit cooperate to fix the circular sample; the detection unit is installed on the loading unit and is located between the first fixing unit and the second fixing unit; the detection unit is used to detect the force displacement of the sample to be pressed when the loading unit presses the sample to be pressed and output a detection signal to the control unit; the sample to be pressed includes: a plurality of punching balls;

[0011] The temperature control unit is connected to the control unit and is used to perform temperature adjustment control according to the control signal output by the control unit.

[0012] In the multifunctional small punch rod experimental device of the present invention, the loading unit comprises: a main loading rod and a plurality of punch ball loading rods;

[0013] The main loading rod and the plurality of punching ball loading rods are arranged on the first fixing unit, and the main loading rod is connected to the driving unit;

[0014] The main loading rod moves according to the driving of the driving unit and drives the multiple punching ball loading rods and the detection unit to move, so as to apply pressure to the multiple punching balls placed under the detection unit.

[0015] In the multifunctional small punch rod experimental device of the present invention, the first fixing unit includes: a plurality of first threaded holes corresponding to the plurality of punch ball loading rods; the detection unit includes: a plurality of force displacement sensors corresponding to the plurality of punch ball loading rods;

[0016] The plurality of first threaded holes are evenly spaced along the circumference, and the first threaded holes cooperate with the threads on the cylindrical surface of the punch ball loading rod;

[0017] Each of the force displacement sensors is arranged below the corresponding punch ball loading rod.

[0018] In the multifunctional small punch rod experimental device of the present invention, the second fixing unit comprises: a plurality of through holes arranged corresponding to the plurality of punch ball loading rods;

[0019] The plurality of through holes are evenly spaced along the circumferential direction, and each through hole is used for a corresponding punch ball loading rod and punch ball to pass through.

[0020] In the multifunctional small punch experimental device of the present invention, a plurality of first positioning holes and a plurality of second threaded holes are arranged around each of the through holes;

[0021] The third fixing unit includes: a plurality of fixing devices; the plurality of fixing devices are arranged corresponding to the plurality of through holes;

[0022] Each of the fixing devices is a barrel-shaped structure, and a central hole is provided at the cylindrical center of the barrel-shaped structure, and a plurality of second positioning holes and a plurality of third threaded holes are provided on the upper surface of the barrel-shaped structure;

[0023] The plurality of second positioning holes are arranged correspondingly to the plurality of first positioning holes, and the plurality of third threaded holes are arranged correspondingly to the plurality of second threaded holes;

[0024] The plurality of second positioning holes cooperate with the plurality of third positioning holes to allow positioning pins to pass through and fix the positioning pins;

[0025] The plurality of second threaded holes cooperate with the plurality of third threaded holes to allow connecting screws to pass through and connect the second fixing unit and the third fixing unit to clamp the circular specimen located between the second fixing unit and the third fixing unit.

[0026] In the multifunctional small punch experimental device of the present invention, the temperature control unit comprises: a plurality of temperature control modules;

[0027] The multiple temperature control modules are correspondingly arranged to the multiple punch ball loading rods and are respectively used for temperature regulation.

[0028] In the multifunctional small punch experimental device of the present invention, each of the temperature control modules comprises: a temperature control box, a heating wire and a temperature sensor;

[0029] The temperature control box is arranged below the corresponding fixing device, and the heating wire and the temperature sensor are arranged inside the temperature control box;

[0030] The heating wire is connected to the control unit and is used to be turned on / off according to the control of the control unit;

[0031] The temperature sensor is used to detect the temperature in the temperature control box and output a temperature detection signal to the control unit.

[0032] In the multifunctional small punch experimental device of the present invention, each of the temperature control modules further comprises: a cooling liquid delivery hole;

[0033] The coolant delivery hole is provided on the temperature box and is used to deliver coolant to the interior of the temperature control box.

[0034] In the multifunctional small punch experimental device of the present invention, the centers of the first threaded hole on the first fixing unit, the through hole on the second fixing unit, and the center hole on the third fixing unit are located on the same axis.

[0035] The application also provides a multifunctional small punch experimental method, which is applied to the multifunctional small punch experimental device and comprises the following steps:

[0036] constructing a small punch experimental model;

[0037] obtaining input parameters and a load of the experiment;

[0038] performing simulation calculation based on the input parameters and the load of the experiment to obtain a plurality of simulated force-displacement curves;

[0039] performing a small punch experiment;

[0040] recording experimental data in the experiment;

[0041] performing analysis according to the experimental data to obtain a plurality of experimental force-displacement curves;

[0042] judging whether the simulated force-displacement curves match the plurality of experimental force-displacement curves;

[0043] if the match is achieved, determining material mechanical property parameters;

[0044] if the match is not achieved, adjusting the input parameters and continuing the simulation calculation until the simulated force-displacement curves match the plurality of experimental force-displacement curves.

[0045] The multifunctional small punch experimental device and method have the following beneficial effects: the device comprises a driving unit, a loading unit, a first fixing unit, a second fixing unit, a third fixing unit, a detection unit, a temperature control unit and a control unit; the driving unit drives the loading unit to move according to a driving signal; the first fixing unit fixes the loading unit, and the second fixing unit and the third fixing unit cooperate to fix a circular sample; the detection unit detects the force displacement of the sample to be tested; the sample to be tested comprises a plurality of punch balls; and the temperature control unit performs temperature adjustment control according to a control signal output by the control unit. The device can determine material mechanical property parameters based on a plurality of groups of data in a single experiment, has high reliability, can solve the problem of single test temperature of the existing clamp, can also realize the acquisition of mechanical property parameters of a plurality of materials at a specific temperature in a single experiment, avoids repeated experiments, and significantly improves experimental efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0046] The application will be further described below with reference to the drawings and embodiments, and the drawings show:

[0047] Figure 1 is a structural schematic diagram of the multifunctional small punch experimental device provided by the application;

[0048] Figure 2is a top view of the multifunctional small punch experimental device provided by the present application.

[0049] Figure 3 is an exploded view of the multifunctional small punch experimental device provided by the present application.

[0050] Figure 4 is a flowchart of the multifunctional small punch experimental method provided by the present application. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0052] The present application provides a multifunctional small punch experimental device and method, which can realize: accurate measurement of the mechanical properties of small punch experimental materials at room temperature; simultaneous testing of small punch experiments of the same material at different temperatures; and simultaneous testing of small punch experiments of different materials at the same temperature. Moreover, the multifunctional small punch experimental device and method provided by the present application have simple experimental steps and reasonable design. The multifunctional small punch experimental device can realize small punch experiments of different diameters of punch balls and different sizes (diameters) of circular samples within a certain range at multiple temperature environments at the same time. By combining multiple single small punch clamps, each corresponding pressure displacement sensor obtains a force displacement curve, and then the mechanical property parameters are obtained through a finite element inversion method. The implementation process is easy and has high precision, which provides a reference for the evaluation of the mechanical properties of the materials to be tested.

[0053] Reference Figures 1 to 3 is a structural diagram of the multifunctional small punch experimental device provided by the present application.

[0054] Specifically, as shown in Figure 1 , the multifunctional small punch experimental device comprises a driving unit, a loading unit, a first fixing unit 3, a second fixing unit 6, a third fixing unit, a detection unit, a temperature control unit, and a control unit. The driving unit and the control unit are not shown in the figure. Figure 1

[0055] In the embodiments of the present application, the driving unit is connected with the loading unit, and is used to drive the loading unit to move according to a driving signal.

[0056] Optionally, in the embodiments of the present application, the control unit is a computer terminal.

[0057] ​In an embodiment of the present invention, a first fixing unit 3, a second fixing unit 6, and a third fixing unit are arranged axially from top to bottom. The first fixing unit 3 is used to fix the loading unit, and the second fixing unit 6 and the third fixing unit cooperate to fix the circular specimen 10. The detection unit is installed on the loading unit and is located between the first fixing unit 3 and the second fixing unit 6. The detection unit is used to detect the force displacement of the specimen to be pressed when the loading unit applies pressure to the specimen and output a detection signal to the control unit. The specimen to be pressed includes: a plurality of punch balls. The temperature control unit is connected to the control unit and is used to perform temperature regulation control according to the control signal output by the control unit.

[0058] Specifically, such as Figure 1 As shown, the loading unit includes a main loading rod 1 and multiple ball loading rods 2. The main loading rod 1 and the multiple ball loading rods 2 are mounted on a first fixing unit 3, and the main loading rod 1 is connected to a driving unit. The main loading rod 1 moves in response to the driving unit, driving the multiple ball loading rods 2 and the detection unit to apply pressure to the multiple balls placed below the detection unit.

[0059] like Figure 2 As shown, the first fixing unit 3 includes: a plurality of first threaded holes 31 corresponding to the plurality of ball loading rods 2; the detection unit includes: a plurality of force displacement sensors 4 corresponding to the plurality of ball loading rods 2; the plurality of first threaded holes 31 are evenly arranged at intervals along the circumferential direction, and the first threaded holes 31 cooperate with the threads on the cylindrical surface of the ball loading rod 2; each force displacement sensor 4 is arranged below the corresponding ball loading rod 2.

[0060] Optionally, in an embodiment of the present invention, the drive unit is a motor, and the electronics are motors of an electronic universal testing machine. The connection between the main loading rod 1 and the motor can be described with reference to an electronic universal testing machine. In a preferred embodiment, six of the multiple ball-loading rods 2 can be provided. Correspondingly, the detection unit can include six force-displacement sensors 4, each positioned below its corresponding ball-loading rod 2.

[0061] In a preferred embodiment, Figure 2 As shown, the first fixing unit 3 can be provided with six first threaded holes 31, which are evenly arranged at 60° intervals around the circumference. Each ball-loading rod 2 has threads on its cylindrical surface, and the threads on the cylindrical surface of the ball-loading rod 2 cooperate with the corresponding first threaded holes 31. A force-displacement sensor 4 is connected below each ball-loading rod 2 (generally via a threaded connection) and is responsible for detecting and collecting the force-displacement curve of the ball in each group of small-strike experiments. The main loading rod 1 moves under the drive of a motor, driving the six ball-loading rods 2 and the force-displacement sensor 4 to move, thereby applying pressure to the ball.

[0062] like Figure 3 As shown, in this embodiment, the second fixing unit 6 includes: a plurality of through holes 61 corresponding to the plurality of punching ball loading rods 2; the plurality of through holes 61 are evenly spaced along the circumferential direction, and each through hole 61 is for the corresponding punching ball loading rod 2 and punching ball to pass through. Among them, a plurality of first positioning holes 62 and a plurality of second threaded holes 63 are arranged around each through hole 61; the third fixing unit includes: a plurality of fixing devices; a plurality of fixing devices are arranged corresponding to the plurality of through holes 61; each fixing device is a barreled structure 11, and a center hole 111 is provided at the cylindrical center of the barreled structure 11, and a plurality of second positioning holes 112 and a plurality of third threaded holes 113 are provided on the upper surface of the barreled structure 11; a plurality of second positioning holes 112 are arranged corresponding to the plurality of first positioning holes 62, and a plurality of third threaded holes 113 are arranged corresponding to the plurality of second threaded holes 63; a plurality of second positioning holes 112 and a plurality of third positioning holes cooperate to allow the positioning pin 8 to pass through and fix the positioning pin 8; a plurality of second threaded holes 63 and a plurality of third threaded holes 113 cooperate to allow the connecting screw 9 to pass through and connect the second fixing unit 6 and the third fixing unit to clamp the circular specimen 10 located between the second fixing unit 6 and the third fixing unit.

[0063] The centers of the first threaded hole 31 on the first fixing unit 3 , the through hole 61 on the second fixing unit 6 , and the center hole 111 on the third fixing unit are located on the same axis.

[0064] In a preferred embodiment, the second fixing unit 6 can be provided with six through holes 61, and the six through holes 61 are evenly arranged every 60° on the circumference. The punch ball loading rod 2 and the punch ball can pass through the through holes 61. Three first positioning holes 62 and three second threaded holes 63 are also provided around each through hole 61.

[0065] In this embodiment, the third fixing unit is a barrel-shaped structure 11. Correspondingly, the third fixing unit is provided with six barrel-shaped structures 11, and the cylindrical center of each barrel-shaped structure 11 is provided with a center hole 111. The upper surface of the barrel-shaped structure 11 is provided with a third threaded hole 113 and a second positioning hole 112. The positioning pin 8 passes through the first positioning hole 62 on the second fixing unit 6 and the second positioning hole 112 on the third fixing unit to achieve the positioning and matching of the second fixing unit 6 and the third fixing unit. The connecting screw 9 passes through the second threaded hole 63 of the second fixing unit 6 and the third threaded hole 113 of the third fixing unit to achieve the overall connection between the second fixing unit 6 and the third fixing unit, thereby achieving the clamping of the circular specimen 10. Among them, the upper surface of the circular specimen 10 is in contact with the bottom surface of the second fixing unit 6, and the lower surface of the circular specimen 10 is in contact with the upper surface of the third fixing unit.

[0066] Optionally, in an embodiment of the present invention, the diameter of the punch ball ranges from 0 to 20 mm, the diameter of the circular specimen 10 ranges from 0 to 40 mm, and the center of the punch ball and the center of the circular specimen 10 are located on the same vertical axis. The centers of the six first threaded holes 31 on the first fixing unit 3, the six through holes 61 on the second fixing unit 6, and the center hole 111 on the third fixing unit are located on the same vertical axis.

[0067] Optionally, in an embodiment of the present invention, the temperature control unit includes: a plurality of temperature control modules; the plurality of temperature control modules are correspondingly provided with the plurality of punch ball loading rods 2, and are respectively used for temperature regulation. In a preferred embodiment, the temperature control unit may be provided with six temperature control modules.

[0068] Optionally, in an embodiment of the present invention, each temperature control module includes: a temperature control box 7 , a heating wire 71 and a temperature sensor 72 .

[0069] The temperature control box 7 is arranged below the corresponding fixing device, and the heating wire 71 and the temperature sensor 72 are arranged inside the temperature control box 7; the heating wire 71 is connected to the control unit and is used to be turned on / off according to the control of the control unit; the temperature sensor 72 is used to detect the temperature inside the temperature control box 7 and output a temperature detection signal to the control unit.

[0070] Furthermore, each temperature control module further includes: a coolant delivery hole 73 ; the coolant delivery hole 73 is provided on the temperature box and is used to deliver coolant to the interior of the temperature control box 7 .

[0071] refer to Figure 4 , Figure 4 A schematic flow chart of the multifunctional small punch experimental method provided by the present invention.

[0072] Among them, the multifunctional small punch experimental method is applied to the multifunctional small punch experimental device disclosed in the embodiment of the present invention.

[0073] Specifically, such as Figure 4 As shown, the multifunctional small punch experimental method includes the following steps:

[0074] Step S101: constructing a small punch experimental model.

[0075] Optionally, in the embodiment of the present invention, the small punch test model may be a Hollomon model. For metal materials, the yield stress range is 200-800 MPa, and the hardening index is 0.1-0.5.

[0076] Step S102: Obtain input parameters and test loads.

[0077] The input parameters are the mechanical properties of the input materials. The test load can be determined based on the actual simulation.

[0078] Step S103: performing simulation calculations based on the input parameters and the test load to obtain multiple sets of simulated force-displacement curves.

[0079] Step S201: Execute a small punch test.

[0080] Step S202: Record test data during the test process.

[0081] Step S203: Analyze the test data to obtain force-displacement curves of multiple groups of tests.

[0082] Step S301: Determine whether the simulated force-displacement curve matches the force-displacement curves of multiple groups of tests; if not, adjust the input parameters and continue the simulation calculation until the simulated force-displacement curve matches the force-displacement curves of multiple groups of tests.

[0083] Step S302: If they match, determine the material mechanical property parameters.

[0084] In the embodiments of the present invention, by inputting any combination of mechanical property parameters into the finite element software, if the simulated load-displacement curve (i.e., the simulated force-displacement curve) matches the experimental load-displacement curve (i.e., the experimental force-displacement curve), the input combination is considered to be the mechanical property parameters of the test material. Specifically, 20 points are uniformly selected on the experimental force-displacement curve and the simulated force-displacement curve, and a match (i.e., agreement) is determined if the error among the 20 points does not exceed ±5%.

[0085] In response to the prior art problem 1, the multifunctional small punch experimental device and method provided by the present invention adopts six groups of punch balls of different sizes (with diameters of 1mm, 2mm, 3mm, 4mm, 5mm and 6mm respectively), loading rods and matching load sensors, which can realize the simultaneous acquisition of 6 groups of different small punch experimental curves; then, by comparing the 6 groups of small punch experimental curves calculated by the mechanical performance parameters input in the finite element model, after repeated iterations, when the 6 groups of load-displacement curves calculated by the mechanical performance parameters input in the finite element model are consistent with the 6 load-displacement curves in the experiment, it can be considered that the mechanical performance parameters input in the finite element software are the mechanical performance parameters of the material to be tested.

[0086] In response to the second problem of the prior art, the present invention sets up six sets of environmental boxes (i.e., temperature control boxes 7) at the test position of the rotating small punch specimen, and sets electric heating wires 71 (to increase the ambient temperature to 400°C), liquid nitrogen interfaces (i.e., cooling liquid delivery holes 73, to reduce the temperature to -196°C) and temperature sensors 72 (ambient temperature feedback) in the environmental boxes. This can solve the problem that the existing fixture test temperature is single and that only one temperature condition can be tested in a single experiment.

[0087] In response to the third problem of the prior art, when it is necessary to simultaneously test the mechanical properties parameters of 2 to 6 materials at a certain specific temperature (-196°C to 400°C), the present invention only needs to adjust the temperature of 6 groups of environmental chambers to a uniform level, and then select 6 punch balls of different materials to perform small punch rod tests on 6 different materials, and perform finite element inversion separately according to the above method, so as to realize the acquisition of the mechanical properties parameters of 6 materials at a specific temperature in a single experiment.

[0088] The present invention has simple steps and reasonable design. By using the present invention, small punch experiments of the same or different materials within a certain range can be carried out simultaneously under a specific temperature (-196°C to 400°C) environment. Small punch experiments can be carried out simultaneously under multiple temperature environments using an environmental chamber. By combining multiple single small punch fixtures, each corresponding force displacement sensor 4 obtains a load curve, combined with the displacement curve of the fixture in the present invention, and then the mechanical performance parameters are obtained through the finite element inversion method. The implementation process is relatively easy and has high precision, which further improves the experimental efficiency and provides a basis for the implementation of small punch experiments in variable temperature environments and the accurate testing of material mechanical properties.

[0089] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0090] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0091] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0092] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. All equivalent variations and modifications within the scope of the claims of the present invention are intended to be covered by the claims of the present invention.

Claims

1. A multifunctional small punch experimental device, characterized in that: include: A driving unit, a loading unit, a first fixing unit, a second fixing unit, a third fixing unit, a detection unit, a temperature control unit, and a control unit; The driving unit is connected to the loading unit and is used to drive the loading unit to move according to a driving signal; The first fixing unit, the second fixing unit, and the third fixing unit are arranged axially from top to bottom, the first fixing unit is used to fix the loading unit, and the second fixing unit and the third fixing unit cooperate to fix the circular sample; the detection unit is installed on the loading unit and is located between the first fixing unit and the second fixing unit; the detection unit is used to perform force displacement detection on the sample to be pressed when the loading unit applies pressure to the sample and output a detection signal to the control unit; The sample to be pressurized includes: a plurality of punch balls; The loading unit includes: a main loading rod and a plurality of punching ball loading rods; the main loading rod and the plurality of punching ball loading rods are arranged on the first fixing unit, and the main loading rod is connected to the driving unit; the main loading rod moves according to the driving of the driving unit and drives the plurality of punching ball loading rods and the detection unit to move, so as to apply pressure to the plurality of punching balls placed below the detection unit; The temperature control unit is connected to the control unit and is used to perform temperature adjustment control according to the control signal output by the control unit; The temperature control unit includes: a plurality of temperature control modules; the plurality of temperature control modules are arranged corresponding to the plurality of punch ball loading rods and are respectively used for temperature regulation.

2. The multifunctional small punch experimental device according to claim 1, characterized in that: The first fixing unit includes: a plurality of first threaded holes corresponding to the plurality of punching ball loading rods; the detection unit includes: a plurality of force displacement sensors corresponding to the plurality of punching ball loading rods; The plurality of first threaded holes are evenly spaced along the circumference, and the first threaded holes cooperate with the threads on the cylindrical surface of the punch ball loading rod; Each of the force displacement sensors is arranged below the corresponding punch ball loading rod.

3. The multifunctional small punch experimental device according to claim 1, characterized in that: The second fixing unit includes: a plurality of through holes corresponding to the plurality of punch ball loading rods; The plurality of through holes are evenly spaced along the circumferential direction, and each through hole is used for a corresponding punch ball loading rod and punch ball to pass through.

4. The multifunctional small punch experimental device according to claim 3, characterized in that: A plurality of first positioning holes and a plurality of second threaded holes are arranged around each of the through holes; The third fixing unit includes: a plurality of fixing devices; the plurality of fixing devices are arranged corresponding to the plurality of through holes; Each of the fixing devices is a barrel-shaped structure, and a central hole is provided at the cylindrical center of the barrel-shaped structure, and a plurality of second positioning holes and a plurality of third threaded holes are provided on the upper surface of the barrel-shaped structure; The plurality of second positioning holes are arranged correspondingly to the plurality of first positioning holes, and the plurality of third threaded holes are arranged correspondingly to the plurality of second threaded holes; The plurality of second positioning holes cooperate with the plurality of first positioning holes to allow positioning pins to pass through and fix the positioning pins; The plurality of second threaded holes cooperate with the plurality of third threaded holes to allow connecting screws to pass through and connect the second fixing unit and the third fixing unit to clamp the circular specimen located between the second fixing unit and the third fixing unit.

5. The multifunctional small punch experimental device according to claim 1, characterized in that: Each of the temperature control modules includes: a temperature control box, a heating wire and a temperature sensor; The temperature control box is arranged below the corresponding fixing device, and the heating wire and the temperature sensor are arranged inside the temperature control box; The heating wire is connected to the control unit and is used to be turned on / off according to the control of the control unit; The temperature sensor is used to detect the temperature in the temperature control box and output a temperature detection signal to the control unit.

6. The multifunctional small punch experimental device according to claim 5, characterized in that: Each of the temperature control modules further comprises: a coolant delivery hole; The coolant delivery hole is provided on the temperature box and is used to deliver coolant to the interior of the temperature control box.

7. The multifunctional small punch experimental device according to claim 4, characterized in that: The centers of the first threaded hole on the first fixing unit, the through hole on the second fixing unit, and the central hole on the third fixing unit are located on the same axis.

8. A multifunctional small punch test method, applied to the multifunctional small punch test device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Construct a small punch experimental model; Obtain input parameters and test loads; Performing simulation calculations based on the input parameters and the test load to obtain multiple sets of simulated force-displacement curves; Perform a small punch test; Record test data during the test; Analyze the test data to obtain force-displacement curves of multiple groups of tests; determining whether the simulated force-displacement curve matches the force-displacement curves of the plurality of groups of tests; If they match, the material mechanical properties parameters are determined; If they do not match, the input parameters are adjusted and the simulation calculation is continued until the simulated force-displacement curve matches the force-displacement curves of the multiple groups of tests.

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