Creep and stress relaxation experimental device for fibers and composite materials

Abstract

The utility model relates to a fiber and composite material creep deformation and stress relaxation experiment device which comprises a machine frame, a fixed pulley block is arranged on the machine frame, a traction rope is wound on the fixed pulley block, and a balance module is connected to the traction end, located on one side of the fixed pulley block, of the traction rope. The traction end, located on the other side of the fixed pulley block, of the traction rope is connected with a load module, a force measuring module is connected between the load module and the rack, and a distance measuring module downwards aligned with the load module is arranged beside the force measuring module. The experimental device has the advantages of high measurement precision, visualization, convenience in operation and the like, can be used for testing creep strain evolution and recovery behaviors of fibers or composite materials under the action of constant stress and stress relaxation behaviors of the fibers or the composite materials under constant strain, can also realize synchronous measurement of the stress relaxation behaviors of the materials after creep, and has a wide application prospect. The problem that material viscoelastic creep and stress relaxation experimental devices are incompatible is solved.

Description

Technical Field

[0001] This utility model relates to an experimental device for creep and stress relaxation of fibers and composite materials, and belongs to the field of mechanical testing technology. Background Technology

[0002] Fiber composites are composite materials composed of fibers and matrix materials. They possess advantages such as high specific strength and specific modulus, good corrosion resistance, and light weight, and are widely used in aerospace, automotive, construction, sporting goods, wind turbine blades, and electronic equipment. Their unique properties give them irreplaceable advantages in these fields. In the process of material performance analysis, the viscoelastic properties of fiber composites are important parameters for measuring their application potential and service life.

[0003] Existing experimental setups typically only perform single viscoelastic property tests and cannot quickly, easily, and effectively transition between viscoelastic creep tests and stress relaxation tests. There is a need to develop a device that can accurately and efficiently test the viscoelasticity of fibers and their composites.

[0004] Therefore, this invention combines creep testing and stress relaxation testing of fiber composite materials into one unit, solving the problem of incompatibility between viscoelastic creep and stress relaxation measurement devices for fiber composite materials. This experimental device has advantages such as high measurement accuracy, visualization, and convenient operation. Utility Model Content

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a fiber and composite material creep and stress relaxation experimental device, which solves the problem of incompatibility between fiber composite material viscoelastic creep and stress relaxation measurement devices.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is: a fiber and composite material creep and stress relaxation experimental device, including a frame, a fixed pulley group is provided on the frame, a traction rope is wound on the fixed pulley group, a balance module is connected to the traction end of the traction rope on one side of the fixed pulley group, a load module is connected to the traction end of the traction rope on the other side of the fixed pulley group, a force measuring module is connected between the load module and the frame, and a distance measuring module facing downward and aligned with the load module is provided next to the force measuring module.

[0007] Preferably, both the balance module and the load module include a weight-bearing frame for holding and adjusting the weights.

[0008] Preferably, the weight-bearing frame of the load module is provided with a lifting and positioning component.

[0009] Preferably, the force measuring module includes a column-type tension / compression sensor, with the top screw of the tension / compression sensor fixed to the frame and the bottom screw connecting the experimental sample strip to the load module.

[0010] Preferably, hooks are fixedly provided on the upper part of both opposite ends of the weight carrier frame, and the hooks are hooked on the crossbar. Slider blocks are fixedly connected to both ends of the crossbar, and the sliders are slidably engaged with slide rails, which are vertically fixedly connected to the frame.

[0011] Preferably, the lifting and positioning assembly includes a set screw, which is screwed onto the sliding side of the load module to secure it to the corresponding slide rail.

[0012] Preferably, the pulling rope is a steel wire rope, and the steel wire rope has two sets, which respectively pull the crossbars on the two opposite outer sides of the weight carrying frame.

[0013] Preferably, a connecting plate is fixedly connected to the frame directly above the load module. The top screw of the tension / compression sensor is fixedly connected to the connecting plate, and the bottom screw is fixedly connected to a pulley frame. An upper pulley for winding the sample strip is installed on the pulley frame, and a lower pulley is installed on the crossbar of the load module directly below the upper pulley.

[0014] Preferably, the connecting plate is further provided with a clearance through hole for making way for the vertical extension section of the traction rope.

[0015] Preferably, the detection head of the ranging module is aligned downwards with the crossbar set on the load module.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention integrates fiber and composite material creep testing and stress relaxation testing devices through a composite structure design, solving the problem of fiber transfer during experimental conversion.

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model.

[0020] Figure 2 This is a schematic diagram of the ranging module.

[0021] Figure 3 This is a schematic diagram of the structure of a tension / compression sensor. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] like Figures 1-3 As shown, this embodiment provides an experimental apparatus for creep and stress relaxation of fibers and composite materials, including a frame 1. Two pairs of fixed pulley groups 2 are arranged on the frame. Each fixed pulley group is wound with a tension rope 3. A balance module 4 is connected to the tension end of the tension rope on one side of the fixed pulley group, and a load module 5 is connected to the tension end of the tension rope on the other side of the fixed pulley group. A force measuring module 6 is connected between the load module and the frame. A distance measuring module 7 facing downward and aligned with the load module is arranged next to the force measuring module.

[0026] In this embodiment of the utility model, both the balance module and the load module include a weight carrier frame 9 for holding and adjusting the weights 8.

[0027] In this embodiment of the utility model, a lifting and positioning component is provided on the weight bearing frame of the load module.

[0028] In this embodiment of the utility model, the force measuring module includes a column-type tension and compression sensor 10, with the top screw of the tension and compression sensor fixed to the frame and the bottom screw connecting the experimental sample strip 11 between the load module.

[0029] In this embodiment of the utility model, hooks 12 are fixedly provided on the upper part of the two opposite ends of the weight carrier frame. The hooks are hooked on the crossbar 13. Slider 14 is fixedly connected to both ends of the crossbar. The sliders are slidably fitted with slide rails 15. The slide rails are vertically fixedly connected to the frame.

[0030] In this embodiment of the utility model, the lifting and positioning assembly includes a set screw 16, which is screwed onto the sliding side of the load module to secure it to the corresponding slide rail.

[0031] In this embodiment of the utility model, the pulling rope is a steel wire rope, and there are two sets of steel wire ropes, which respectively pull the crossbars on the two opposite outer sides of the weight carrying frame.

[0032] In this embodiment of the utility model, a connecting plate 17 is fixedly connected to the frame directly above the load module. The top screw of the tension / compression sensor is fixedly connected to the connecting plate, and the bottom screw is fixedly connected to a pulley frame 18. An upper pulley 19 for winding the sample strip is installed on the pulley frame, and a lower pulley 20 is installed on the crossbar of the load module directly below the upper pulley. The connecting plate is also provided with a clearance through hole 21 for making way for the vertical extension of the traction rope.

[0033] In this embodiment of the invention, an internally threaded hole 28 is provided on the side of the groove of the upper pulley, and a fastening bolt 22 is screwed into the internally threaded hole to fix the end of the sample strip. When fixing the end of the sample strip, the two free ends of the sample strip are brought together and then passed through the internally threaded hole from the inside to the outside, and the fastening bolt is locked to press the two free ends.

[0034] This invention uses a method of installing fastening bolts on the upper pulley to fix the floating / free ends of fibers or composite materials during the experiment, making winding more convenient, reducing the time of experimental preparation, and improving testing efficiency.

[0035] In this embodiment of the invention, the ranging module is mounted on a connecting plate. The ranging module includes a rangefinder fixing block 23 and a laser rangefinder 24. The rangefinder fixing block is fixed to the connecting plate through two fixing holes 25 distributed on its top; the laser rangefinder is fixed to the linear fixing hole 26 on the rangefinder fixing block by bolts.

[0036] In this embodiment of the invention, the detection head of the ranging module is aligned downwards with the crossbar set on the load module.

[0037] In this embodiment of the invention, a display module 27 is installed on the lower right side of the front of the frame. Data measured by the laser rangefinder and the tension / compression sensor are transmitted to the display module for recording via a data acquisition card.

[0038] In this embodiment of the invention, the frame is a cuboid frame made of aluminum profiles.

[0039] An experimental method for a fiber and composite material creep and stress relaxation test apparatus is performed according to the following steps:

[0040] (1) Creep test method: First, place the device on a horizontal test platform and set the device to the unlocked state (the set screw is not tightened). Add a suitable weight to the weight bearing frame of the balance module to make the load module reach balance. Wrap the fiber or composite material sample strip between the upper and lower pulleys and record the original data. Start the distance measuring module and the force measuring module and reset the operation. Add a certain number of weights to the weight bearing frame of the load module to reach the preset constant stress and start the experiment. After the load is applied in the load module, its horizontal bar moves downward and the sample strip is subjected to force and creep. The display module monitors and records the force and displacement changes within a certain time. After the test time required for the creep test is reached, remove the weights. The display module monitors and records the force value change of the force measuring module. After the test time required for creep recovery is reached, remove the sample strip, put the modules of the device back in place, and end the experiment.

[0041] (2) Stress relaxation test method: Place the device on a horizontal test platform, set the device to the unlocked state (the set screw is not tightened), add a suitable weight to the weight bearing box of the balance module to make the load module reach balance; wrap the fiber or composite material sample strip between the upper and lower pulleys and record the original data; start the distance measuring module and the force measuring module and reset the operation; add a certain number of weights to the weight bearing box of the load module to reach the preset constant strain, and lock the position of the load module with the set screw; the display module monitors and records the force value change of the force measuring module; after the test time required for stress relaxation is reached, loosen the set screw, remove the weight and then remove the sample strip, put the modules of the device back in place, and end the experiment;

[0042] (3) Simultaneous test method for stress relaxation after creep: Place the device on a horizontal test bench, set the device to the unlocked state, add a weight of appropriate weight to the weight bearing box of the balance module to make the load module reach balance; wrap the fiber or composite material sample strip between the upper and lower pulleys and record the original data; start the distance measuring module and the force measuring module and reset the operation; add a certain number of weights to the weight bearing box of the load module to reach the preset constant stress and start the experiment; after the test time required for creep test is reached, lock the position of the load module with the set screw; the display module monitors and records the force value change of the force measuring module; after the test time required for stress relaxation is reached, loosen the set screw, remove the weight and remove the sample strip, return each module of the device to its position, and end the experiment.

[0043] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A device for creep and stress relaxation experiments on fibers and composites, characterized by: Including frame, be provided with fixed pulley set on frame, the fixed pulley set is around provided with pull rope, the pull rope is connected with balance module on the pull end of fixed pulley set one side, the pull rope is connected with load module on the pull end of fixed pulley set other side, load module is connected with force measuring module between frame, the lateral of force measuring module is provided with range finding module and is aimed at load module downwards.

2. The fiber and composite creep and stress relaxation apparatus of claim 1, wherein: Balance module and load module all include the weight-bearing frame for containing weight and lifting adjustment.

3. The fiber and composite creep and stress relaxation apparatus of claim 2, wherein: The weight-bearing frame of load module is provided with lifting positioning assembly.

4. The fiber and composite creep and stress relaxation apparatus of claim 1, wherein: The force measuring module includes column type tension and compression force sensor, the top end screw rod of tension and compression force sensor is fixedly connected with frame, and the bottom end screw rod is connected with experimental sample strip between load module.

5. The fiber and composite creep and stress relaxation apparatus of claim 3, wherein: The upper part of both opposite end sides of weight-bearing frame is fixedly provided with hook part, the hook part is hung on cross bar, both end sides of cross bar are fixedly connected with sliding block, and the sliding block is slidingly matched with slide rail, and the slide rail is vertically fixedly connected on frame.

6. The fiber and composite creep and stress relaxation apparatus of claim 5, wherein: The lifting positioning assembly includes tight screw, and the tight screw is screwed on the sliding side of load module to be tightened on corresponding slide rail.

7. The fiber and composite creep and stress relaxation apparatus of claim 5, wherein: The pull rope is steel wire rope, and the steel wire rope has two groups and pulls the cross bar on the two opposite outer sides of weight-bearing frame respectively.

8. The fiber and composite creep and stress relaxation apparatus of claim 4, wherein: The frame is fixedly connected with connecting plate above load module, the top end screw rod of tension and compression force sensor is fixedly connected on connecting plate, the bottom end screw rod is fixedly connected with pulley frame, the upper pulley for winding sample strip is installed on pulley frame, and the lower pulley is installed on the cross bar of load module below upper pulley.

9. The fiber and composite creep and stress relaxation apparatus of claim 8, wherein: The connecting plate is further provided with let-out through hole for letting out the vertical extension section of pull rope.

10. The fiber and composite creep and stress relaxation apparatus of claim 1, wherein: The detection head of range finding module is aimed at the cross bar provided on load module downwards.

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