A stress test device for composite materials

Abstract

The present invention provides a stress test device for composite materials, comprising a box, a humidifier, a heater, and a plurality of sample clamping systems arranged in the inner cavity of the box from top to bottom, each sample clamping system comprising a top plate and a bottom plate connected by a plurality of uniformly fixed guide posts, a plurality of connectors A, a plurality of connectors B, a plurality of spring bolt assemblies and a plurality of clamps, the two ends of each spring bolt assembly are respectively connected to the corresponding guide post through the corresponding connector A and to the corresponding clamp through the corresponding connector B, and the assembled spring bolt assembly, connector A, connector B, and clamp are integrally located in the cavity formed by the top plate and the bottom plate. The present invention more realistically simulates the situation in which the composite material is subjected to complex stress and the environment in which it is located in an application, and effectively reflects the gradient effect of the weakening of the performance of the composite material component over time.

Description

Technical Field

[0001] The invention relates to a stress testing device for composite materials, belonging to the technical field of testing equipment. Background Art

[0002] In recent years, with the acceleration of urbanization and the growth of transportation demand, EMUs have become an important part of the modern transportation system. Modern EMUs are widely used in intercity transportation and high-speed railways due to their advantages such as high speed, high efficiency and environmental protection. However, the challenges faced by EMU trains when running in high temperature and humid environments are becoming increasingly prominent. Due to different geographical environments and climatic conditions, in some coastal cities and areas with humid climates, such as cities in southern coastal provinces such as Guangdong and Fujian, EMU trains need to cope with the challenges of humid environments when running in these cities and areas due to their proximity to the sea and the existence of humid climates. The presence of humid environments may cause corrosion and aging of the materials used in EMU trains, as well as complex temperature changes and humidity changes and other unfavorable factors, which in turn affect the performance and safety of EMU trains.

[0003] Composite materials have the characteristics of light weight, high strength and corrosion resistance, so they are widely used in different parts and structures in EMU trains, such as car bodies, bogies, interior materials, etc., to reduce the weight of trains, improve performance, and reduce energy consumption. When high-speed trains run under high temperature and humid environment, composite materials face a series of problems that may be caused by high temperature and humid environment, such as stress effects caused by humidity changes, corrosion and accelerated aging, etc. In order to ensure the safe operation of EMU trains and improve the resistance to humidity changes and performance stability of composite materials, it is necessary to conduct complex stress tests on composite materials in humid environments.

[0004] At present, universal material testing machines are generally used for tensile and compression tests of composite material samples. Their main structure is a single-space column structure, which can be used for tensile, bending, shear and other tests with different fixtures.

[0005] However, the above-mentioned existing tensile or compression universal material testing machines have the following disadvantages: 1. The existing universal material testing machines cannot complete the loading of complex stresses for a long time, and they cannot simulate the environment of temperature and humidity changes; 2. They can only perform tension and compression tests in a single direction. Composite materials need to withstand complex multi-directional tension and compression stresses in actual applications. The test device cannot reasonably simulate the situation where materials are subjected to complex stresses in real applications. 3. The existing universal material testing machines can only test one sample per test, and the experimental efficiency is low. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a stress testing device for composite materials, which can simulate the gradient effect of composite material component performance weakening over time under different temperature, humidity and complex stress conditions.

[0007] In order to solve the above technical problems, the present invention provides a stress test device for composite materials, comprising a box, a humidifier, a heater, and a plurality of sample clamping systems arranged in the inner cavity of the box from top to bottom, the mist outlet of the humidifier is arranged in the inner cavity of the box, the heating element of the heater is placed in the inner cavity of the box, and the control system of the humidifier and the control system of the heater are both arranged outside the box;

[0008] Each sample clamping system includes a top plate and a bottom plate connected by a plurality of uniformly fixed guide posts, a plurality of connectors A, a plurality of connectors B, a plurality of spring bolt assemblies and a plurality of clamps. The number of spring bolt assemblies, the number of connectors A, the number of connectors B and the number of clamps are consistent, the number of spring bolt assemblies is not greater than the number of guide posts, the two ends of each spring bolt assembly are respectively connected to the corresponding guide post through the corresponding connector A and to the corresponding clamp through the corresponding connector B, and the assembled combination of the spring bolt assembly, connector A, connector B and clamp is located in the cavity formed by the top plate and the bottom plate.

[0009] Preferably, one end of the connecting member A is a clamping ring, the end surface of the other end of the connecting member A is circular, threaded holes A are arranged at the ends of the clamping ring, bolts A pass through the two threaded holes A in sequence to fix the guide column in the corresponding clamping ring, a threaded hole B is arranged at the center of the circular end surface of the connecting member A, and four threaded holes C are evenly arranged around the threaded hole B;

[0010] The spring bolt assembly includes a bolt B, four bolts C, a nut B arranged in sequence along the horizontal direction, a first end cover, a spring, and a second end cover. The first end cover and the second end cover are both provided with a threaded hole D. One end of the bolt B passes through the nut B, the first end cover, the spring, and the second end cover in sequence and then has a clearance fit with the threaded hole F on the connecting member B. The other end of the bolt B has a clearance fit with the threaded hole B of the connecting member A. The bolt B has a clearance fit with the threaded holes D of the first end cover and the second end cover. A threaded hole E is provided on the first end cover at a position relative to each threaded hole C. One end of each bolt C passes through the corresponding threaded hole E and the corresponding threaded hole C in sequence and then is threadedly connected with the nut C.

[0011] Preferably, the second end cover is fixedly connected to the connecting member B; or, the second end cover and the connecting member B are integral.

[0012] Preferably, the diameter of the threaded hole B is 24 mm, and the diameter of the threaded hole C is 8 mm.

[0013] Preferably, the top plate and the bottom plate of each sample clamping system are connected by 8 guide pillars, the top plate and the bottom plate are both circular, and the angle between the line connecting two adjacent guide pillars and the center of the bottom plate is 45°.

[0014] Preferably, the connecting member B is connected to the corresponding clamp via a pin.

[0015] Preferably, the end surface of the connecting member B is circular.

[0016] Preferably, the outer wall of the box is covered with thermal insulation cotton.

[0017] Preferably, the clamp is a wedge-shaped clamp.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention is provided with a humidifier and a heater, which can control the ambient temperature and humidity in the box according to actual needs, and can change the positions of two adjacent spring bolt assemblies according to actual needs, so as to realize the application of multi-directional complex stresses with angles of different sizes, thereby effectively improving its versatility. At the same time, it more realistically simulates the situation in which the composite materials are subjected to complex stresses and the environment in which they are located in the application, and effectively reflects the gradient effect of the weakening of the performance of the composite material components over time.

[0020] 2. The present invention compresses the first end cover through the nut B of the spring bolt assembly, and then transmits the pressure to the sample through the spring, thereby applying a pressure load to the sample. The tension of the bolt C of the spring bolt assembly drives the spring to stretch, and the spring transmits the tension to the sample, thereby applying a tensile load to the sample. It can choose to apply a pressure load or a tensile load to the sample according to actual conditions, which overcomes the defect that only bidirectional tension can be applied to the sample, and further realistically simulates the situation where the composite material is subjected to complex stress in the application.

[0021] 3. The present invention can simultaneously perform multi-axial stress tests on a plurality of specimens of different shapes, which not only improves the test efficiency but also further enhances its versatility.

[0022] 4. The present invention is a purely mechanical structure, can be placed in a humid environment for a long time, has a simple structure, is easy to maintain, easy to install, has low cost and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention.

[0024] Figure 2 It is a structural schematic diagram of the assembled spring bolt assembly, connector A, connector B, and clamp of the present invention.

[0025] Figure 3It is a schematic diagram of the structure of the sample clamping system of the present invention (two spring bolt assemblies are provided).

[0026] Figure 4 It is a structural schematic diagram of a state in which the sample clamping system of the present invention applies pressure to the sample.

[0027] Figure 5 A structural schematic diagram of a state in which a sample clamping system of the present invention applies a pulling force to a sample.

[0028] Figure numerals: top plate 1, guide column 2, bottom plate 3, clamp 4, spring bolt assembly 5, bolt A6, connector A7, first end cover 8, spring 9, second end cover 10, bolt B11, nut B12, bolt C13, second end cover 14, pin 15, box body 16, heating element 17, heater control system 18, sample 19, mist outlet 20, humidifier control system 21, sample clamping system 22, connector B23. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below in conjunction with the embodiments and drawings. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0030] refer to Figure 1 A stress test device for composite materials includes a box 16, a humidifier, a heater, and a plurality of sample clamping systems 22 arranged in the inner cavity of the box 16 from top to bottom. A plurality of samples of different shapes can be tested in sequence, such as a cross shape and a cross shape. The mist outlet 20 of the humidifier is arranged in the inner cavity of the box 16, and the heating element 17 of the heater is placed in the inner cavity of the box 16. The humidifier control system 21 and the heater control system 18 are both arranged outside the box 16 to provide different ambient humidity and ambient temperature for the test, so as to more realistically simulate the environment of the sample in the application. When the device is running, the box is closed;

[0031] refer to Figure 2Each sample clamping system 22 includes a top plate 1 and a bottom plate 3 connected by a plurality of uniformly fixed guide posts 2, a plurality of connectors A7, a plurality of connectors B23, a plurality of spring bolt assemblies 5 and a plurality of clamps 4. The number of spring bolt assemblies 5, the number of connectors A7, the number of connectors B23 and the number of clamps 4 are consistent. The number of spring bolt assemblies 5 is not greater than the number of guide posts 2. Both ends of each spring bolt assembly 5 are respectively connected to the corresponding guide post 2 through the corresponding connector A7 and to the corresponding clamp 4 through the corresponding connector B23. The number of guide posts 2 and the number of spring bolt assemblies 5 can be determined according to the actual situation of the sample. The installation position of the spring bolt assembly 5 can be determined according to the actual situation of the sample to facilitate the application of complex multi-axial pressure or tension to the sample 19, so as to more realistically simulate the stress that the sample 19 is subjected to in the application. The assembled combination of the spring bolt assembly 5, the connector A7, the connector B23 and the clamp 4 is located in the cavity formed by the top plate 1 and the bottom plate 3.

[0032] refer to Figure 3 Preferably, one end of the connecting member A7 is a clamping ring, and the end face of the other end of the connecting member A7 is circular. The diameter of the clamping ring is consistent with the diameter of the guide column. The ends of the clamping ring are provided with threaded holes A. The bolts A6 pass through the two threaded holes A in sequence to fix the guide column 2 in the corresponding clamping ring. The center of the circular end face of the connecting member A7 is provided with a threaded hole B, and four threaded holes C are evenly provided around the threaded hole B.

[0033] The spring bolt assembly 5 includes a bolt B11, four bolts C13, a nut B12 arranged in sequence along the horizontal direction, a first end cover 8, a spring 9, and a second end cover 10. The first end cover 8 and the second end cover 10 are both provided with a threaded hole D. One end of the bolt B11 passes through the nut B12, the first end cover 8, the spring 9, and the second end cover 10 in sequence and then has a clearance fit with the threaded hole F on the connecting member B23. The other end of the bolt B11 has a clearance fit with the threaded hole B of the connecting member A7. The bolt B11 has a clearance fit with the threaded hole D of the first end cover 8 and the second end cover 10. A threaded hole E is provided at a position on the first end cover 7 relative to each threaded hole C. One end of each bolt C13 passes through the corresponding threaded hole E and the corresponding threaded hole C in sequence and then is threadedly connected with the nut C. In the test, the bolt C is removed and the nut B12 is moved, and pressure can be applied to the sample 19. In the test, the nut B is removed and the nut C is tightened, and tension can be applied to the sample 19 through the bolt C13.

[0034] Optionally, the second end cover 10 is fixedly connected to the connecting piece B23; or, the second end cover 10 and the connecting piece B23 are integrated.

[0035] Preferably, the diameter of the threaded hole B is 24 mm, and the diameter of the threaded hole C is 8 mm.

[0036] Optionally, the top plate 1 and the bottom plate 3 of each sample clamping system 22 are connected by 8 guide pillars 2. For samples of different shapes, such as a cross shape and a crisscross shape, the top plate 1 and the bottom plate 2 are both circular, and the angle between the line connecting the centers of two adjacent guide pillars 2 and the bottom plate 3 is 45°, thereby achieving the application of multi-directional complex stress with a minimum angle of 45°.

[0037] Preferably, the connecting member B23 is connected to the corresponding clamp 4 via a pin 15.

[0038] Preferably, the end face of the connecting member B23 is circular.

[0039] Preferably, the outer wall of the box body 16 is covered with thermal insulation cotton, which can effectively save energy.

[0040] Preferably, the clamp 4 is a wedge-shaped clamp, the jaws of which are open-type in design, so as to facilitate replacement of the clamping faces and clamping of the sample 19 , and the clamp has a load capacity of 250 KN.

[0041] refer to Figure 4 The device is used to perform a bidirectional compression test on a cross-shaped specimen. At this time, the four bolts C13 are removed, and the first end cover is squeezed by rotating the nut B12. The pressure of the nut B12 drives the spring to compress to transfer the compression load, and the spring then transfers the compression load to the specimen 19 through the fixture 4.

[0042] refer to Figure 5 , use this device to do a biaxial tensile test on a cross-shaped specimen. At this time, take out the nut B12, and tighten the four nuts C so that the tension of the four bolts C13 drives the spring to stretch, and apply a tensile load to the specimen 19 through the fixture 4.

[0043] During the test, the humidifier and the heater are used to provide the inner cavity of the box 16 with the required humidity and temperature.

[0044] After stress is applied to the composite material sample, it is placed in a box 16 with a set temperature and humidity for testing. After a set time, the sample is taken out for testing and analysis to observe the degree of weakening of its performance.

[0045] The complex stress that meets the actual needs can be simulated by changing the number and position of the spring bolt assemblies 5 .

[0046] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A stress testing device for composite materials, characterized in that: The invention comprises a box (16), a humidifier, a heater, and a plurality of sample clamping systems (22) arranged from top to bottom in the inner cavity of the box (16); a mist outlet (20) of the humidifier is arranged in the inner cavity of the box (16); a heating element (17) of the heater is placed in the inner cavity of the box (16); and a humidifier control system (21) and a heater control system (18) are both arranged outside the box (16); Each sample clamping system (22) comprises a top plate (1) and a bottom plate (3) connected by a plurality of uniformly fixed guide posts (2), a plurality of connecting members A (7), a plurality of connecting members B (23), a plurality of spring bolt assemblies (5) and a plurality of clamps (4), wherein the number of the spring bolt assemblies (5), the number of the connecting members A (7), the number of the connecting members B (23) and the number of the clamps (4) are the same, and the number of the spring bolt assemblies (5) is not greater than the number of the guide posts (2), and the two ends of each spring bolt assembly (5) are respectively connected to the corresponding guide post (2) by the corresponding connecting member A (7) and to the corresponding clamp (4) by the corresponding connecting member B (23), and the assembled spring bolt assembly (5), the connecting member A (7), the connecting member B (23) and the clamp (4) are located in a cavity formed by the top plate (1) and the bottom plate (3); One end of the connecting member A (7) is a clamping ring, and the end surface of the other end of the connecting member A (7) is circular. The ends of the clamping ring are provided with threaded holes A. Bolts A (6) pass through the two threaded holes A in sequence to fix the guide column (2) in the corresponding clamping ring. The center of the circular end surface of the connecting member A (7) is provided with a threaded hole B, and four threaded holes C are evenly provided around the threaded hole B. The spring bolt assembly (5) comprises a bolt B (11), four bolts C (13), a nut B (12) arranged in sequence in a horizontal direction, a first end cover (8), a spring (9), and a second end cover (10), wherein the first end cover (8) and the second end cover (10) are both provided with a threaded hole D, one end of the bolt B (11) passes through the nut B (12), the first end cover (8), the spring (9), and the second end cover (10) in sequence and then is loosely fitted with the threaded hole F on the connecting member B (23), the other end of the bolt B (11) is loosely fitted with the threaded hole B of the connecting member A (7), the bolt B (11) is loosely fitted with the threaded hole D of the first end cover (8) and the second end cover (10), a threaded hole E is provided on the first end cover (8) at a position corresponding to each threaded hole C, one end of each bolt C (13) passes through the corresponding threaded hole E and the corresponding threaded hole C in sequence and then is threadedly connected with the nut C; The top plate (1) and the bottom plate (3) of each sample clamping system (22) are connected by eight guide pillars (2), the top plate (1) and the bottom plate (3) are both circular, and the angle between the line connecting the centers of two adjacent guide pillars (2) and the bottom plate (3) is 45°. o .

2. The stress testing device for composite materials according to claim 1, characterized in that: The second end cover (10) is fixedly connected to the connecting piece B (23); or the second end cover (10) and the connecting piece B (23) are integral.

3. The stress testing device for composite materials according to claim 2, characterized in that: The diameter of the threaded hole B is 24 mm, and the diameter of the threaded hole C is 8 mm.

4. The stress testing device for composite materials according to claim 3, characterized in that: The connecting member B (23) is connected to the corresponding clamp (4) via a pin (15).

5. The stress testing device for composite materials according to claim 4, characterized in that: The end surface of the connecting member B (23) is circular.

6. The stress testing device for composite materials according to claim 5, characterized in that: The outer wall of the box body (16) is covered with thermal insulation cotton.

7. The stress testing device for composite materials according to claim 6, characterized in that: The clamp (4) is a wedge-shaped clamp.

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