A Post-Impact Compression Test System and Method for a Composite Material

Abstract

The present invention relates to the technical field of composite material testing, and particularly relates to a post-impact compression testing system and method for composite materials. The system includes a first fixture and a second fixture. The first fixture includes a fixed seat and a clamping assembly disposed on the fixed seat. The clamping assembly is used for clamping a test piece, and the test piece is a composite laminate. The second fixture includes two relatively movable bases and an abutting assembly disposed on the bases. The two bases are used for sleeving on the outer periphery of the fixed seat so that when the two bases approach each other, the fixed seat is locked. The abutting assembly is used for abutting against the clamping assembly to urge the clamping assembly to clamp and center the test piece. This solution can improve the accuracy of the post-impact compression test results of composite materials.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material testing, and particularly relates to a compression-after-impact testing system and method for composite materials. Background Art

[0002] Compression-After-Impact (CAI) testing is an important test in the field of composite material testing (such as aerospace composite materials). By measuring the compression performance of a composite laminate after impact, the impact resistance and damage tolerance performance of the composite material are evaluated.

[0003] In related technologies, usually, a composite laminate after being impacted is placed in an anti-instability fixture, and then experiments are carried out under a compression load. Currently, all CAI tests are completed manually. For example, an operator first draws a line on the central plane of the fixture, adjusts the position of the limit slider on the fixture, and fixes the slider with screws so that the center of the specimen (i.e., the composite laminate) is aligned with the center of the fixture and clamped, thereby achieving centering. However, the CAI test has high requirements for the clamping quality of the specimen, so related technologies often introduce manual errors, which may lead to inaccurate test results.

[0004] Therefore, there is an urgent need for a compression-after-impact testing system and method for composite materials to solve the above technical problems. Summary of the Invention

[0005] Embodiments of the present invention provide a compression-after-impact testing system and method for composite materials, which can improve the accuracy of the compression-after-impact test results of composite materials.

[0006] In a first aspect, embodiments of the present invention provide a compression-after-impact testing system for composite materials, including:

[0007] A first fixture, including a fixed seat and a clamping assembly arranged on the fixed seat, the clamping assembly being used for clamping a specimen, and the specimen being a composite laminate;

[0008] A second fixture, including two relatively movable bases and an abutting assembly arranged on the bases, the two bases being used for sleeving on the outer periphery of the fixed seat so that the two bases lock the fixed seat when approaching each other, and the abutting assembly being used for abutting against the clamping assembly to urge the clamping assembly to clamp and center the specimen.

[0009] In a possible design, the first fixture further includes two support side plates, the two support side plates being movably arranged on the fixed seat, and the specimen being located between the two support side plates;

[0010] The clamping assembly includes two horizontal sliders and four vertical sliders. The two horizontal sliders are movably arranged on the fixed seat, and the specimen is located between the two horizontal sliders. Among them, two of the vertical sliders are movably arranged on one of the support side plates, and the other two vertical sliders are movably arranged on the other support side plate. The specimen is located between the two vertical sliders arranged on the same support side plate.

[0011] In a possible design, the two horizontal sliders and the fixed seat are connected by a first fastener, and the four vertical sliders and the support side plates are connected by a second fastener;

[0012] The system further includes an electric tightening gun. The electric tightening gun is provided with a torque sensor and is used to tighten the first fastener and the second fastener. Among them, during the tightening process, when the torque sensor reaches a preset value, the tightening action is stopped.

[0013] In a possible design, the two horizontal sliders and the four vertical sliders are both provided with strip-shaped holes to enable movement relative to the fixed seat and the support side plates.

[0014] In a possible design, the first clamp and the second clamp are both located on the lower pressing plate of a testing machine for testing compressive performance. The bottoms of the two bases are both provided with arc-shaped grooves, so that when the two bases lock the fixed seat, the two arc-shaped grooves are sleeved on the outer periphery of the lower pressing plate, thereby realizing the centering of the specimen relative to the lower pressing plate.

[0015] In a possible design, the second clamp further includes a lead screw and a driving mechanism. The lead screw is arranged between the two bases, and the driving mechanism is used to drive the two bases to approach or move away along the lead screw.

[0016] In a possible design, the approaching or separating ends of the two bases include open ends and connecting ends. The lead screw is arranged at the connecting ends, and the open ends are used to insert into the fixed seat when the two bases are in a separated state, so as to sleeve the two bases on the outer periphery of the fixed seat.

[0017] In a possible design, the abutting assembly includes four rotatable electric push rods. When each electric push rod is in a vertical state, the electric push rod is used to abut against the vertical slider. When each electric push rod is in a horizontal state, the electric push rod is used to abut against the horizontal slider.

[0018] In a possible design, the second fixture further includes a displacement sensor, which is used to indicate the in-place state of the base and the abutting component.

[0019] In a second aspect, an embodiment of the present invention provides a method for post-impact compression testing of a composite material. Using the system described in any one of the above, the method includes:

[0020] Place the specimen in the clamping assembly;

[0021] Set two of the bases around the outer periphery of the fixing seat;

[0022] Bring the two bases closer together to lock the fixing seat;

[0023] Press the abutting component against the clamping assembly to prompt the clamping assembly to clamp and align the specimen.

[0024] An embodiment of the present invention provides a post-impact compression testing system and method for a composite material. By using the clamping assembly of the first fixture to clamp the specimen, and then using the second fixture to clamp the fixing seat and the clamping assembly of the first fixture, the clamping assembly can be prompted to clamp and align the specimen, solving the problems of cumbersome manual operation and large errors, and improving the accuracy of the post-impact compression test results of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 FIG. is a schematic structural diagram of a post-impact compression testing system for a composite material provided by an embodiment of the present invention;

[0027] Figure 2 FIG. is another schematic structural diagram of a post-impact compression testing system for a composite material provided by an embodiment of the present invention;

[0028] Figure 3 is Figure 1 a bottom view of the post-impact compression testing system for the composite material shown.

[0029] Reference Numerals:

[0030] 10 - Specimen;

[0031] 20 - Lower platen;

[0032] 1 - First fixture;

[0033] 11 - Fixed seat;

[0034] 12 - Clamping assembly;

[0035] 121 - Horizontal slider;

[0036] 122 - Vertical slider;

[0037] 123 - Strip hole;

[0038] 13 - Support side plate;

[0039] 14 - First fastener;

[0040] 15 - Second fastener;

[0041] 2 - Second fixture;

[0042] 21 - Base;

[0043] 211 - Arc groove;

[0044] 22 - Abutting assembly;

[0045] 221 - Electric push rod;

[0046] 23 - Lead screw;

[0047] 24 - Open end;

[0048] 25 - Connection end. Detailed implementation manners

[0049] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] As Figure 1 shown, an embodiment of the present invention provides an in - plane shear strength test system and method for composite materials. The system includes a first fixture 1 and a second fixture 2, wherein:

[0051] The first fixture 1 includes a fixed seat 11 and a clamping assembly 12 disposed on the fixed seat 11. The clamping assembly 12 is used to clamp a specimen 10, and the specimen 10 is a composite laminate;

[0052] The second fixture 2 includes two relatively movable bases 21 and a contact component 22 disposed on the bases 21. The two bases 21 are used to sleeved on the outer periphery of the fixed seat 11 so that the two bases 21 lock the fixed seat 11 when approaching each other. The contact component 22 is used to contact with the clamping component 12 to prompt the clamping component 12 to clamp and center the test piece 10.

[0053] In this embodiment, the clamping component 12 of the first fixture 1 is used to clamp the test piece 10, and then the second fixture 2 is used to clamp the fixed seat 11 and the clamping component 12 of the first fixture 1, so as to prompt the clamping component 12 to clamp and center the test piece 10, solving the problems of cumbersome manual operation and large error, and improving the accuracy rate of the post-impact compression test results of the composite material.

[0054] It can be understood that the two bases 21 enclose a rectangular groove, and the contour of the rectangular groove matches the contour of the fixed seat 11. Therefore, the two relatively movable bases 21 can be used to lock the fixed seat 11.

[0055] As mentioned above, at present, all CAI tests are completed manually. The operator first draws a line on the central plane of the fixture, adjusts the position of the limit slider on the fixture, and fixes the slider with screws so that the center of the test piece (i.e., the composite laminate) is aligned with the center of the fixture and clamped, thereby achieving centering. And the above solution is to increase the second fixture 2, so that the two bases 21 of the second fixture 2 are sleeved on the outer periphery of the fixed seat 11 so that the two bases 21 lock the fixed seat 11 when approaching each other, and the contact component 22 of the second fixture 2 contacts with the clamping component 12 to prompt the clamping component 12 to clamp and center the test piece 10. Therefore, the above solution can improve the accuracy rate of the post-impact compression test results of the composite material.

[0056] In an embodiment of the present invention, the first fixture 1 further includes two supporting side plates 13. The two supporting side plates 13 are movably disposed on the fixed seat 11, and the test piece 10 is located between the two supporting side plates 13;

[0057] The clamping component 12 includes two horizontal sliders 121 and four vertical sliders 122. The two horizontal sliders 121 are movably disposed on the fixed seat 11, and the test piece 10 is located between the two horizontal sliders 121. Among them, two vertical sliders 122 are movably disposed on one of the supporting side plates 13, and the other two vertical sliders 122 are movably disposed on the other supporting side plate 13. The test piece 10 is located between the two vertical sliders 122 disposed on the same supporting side plate 13.

[0058] In this embodiment, two support side plates 13 that can be movably arranged relative to the fixed seat 11 can preliminarily clamp test pieces 10 of different sizes, and the specific stable clamping is achieved by two horizontal sliders 121 and four vertical sliders 122.

[0059] Of course, the support side plates 13 of the first fixture 1 may not be set to be movable, and the clamping assembly 12 may also be set as an integral slider, which is not limited herein.

[0060] In an embodiment of the present invention, the two horizontal sliders 121 are connected to the fixed seat 11 through the first fasteners 14, and the four vertical sliders 122 are connected to the support side plates 13 through the second fasteners 15;

[0061] The above system further includes an electric tightening gun (not shown in the figure), the electric tightening gun is arranged on the torque sensor, and the electric tightening gun is used to tighten the first fasteners 14 and the second fasteners 15; wherein, during the tightening process, when the torque sensor reaches a preset value, the tightening action is stopped.

[0062] In this embodiment, by using the electric tightening gun to tighten the first fasteners 14 and the second fasteners 15, during the tightening process, when the torque sensor reaches a preset value, the tightening action is stopped, thereby realizing automatic fixation. Compared with the related art using manual fixation, this method can ensure that the pre-tightening forces of each of the first fasteners 14 and the second fasteners 15 are the same, and thus can further ensure the centering effect of the test piece 10.

[0063] In some embodiments, a robotic arm can be used to drive the movement of the electric tightening gun, thereby realizing automatic assembly. Of course, it can also be that a person holds the electric tightening gun by hand, which is not limited herein.

[0064] In an embodiment of the present invention, the two horizontal sliders 121 and the four vertical sliders 122 are both provided with elongated holes 123 to enable movement relative to the fixed seat 11 and the support side plates 13.

[0065] In this embodiment, by providing the elongated holes 123, the movement of the two horizontal sliders 121 relative to the fixed seat 11 and the movement of the four vertical sliders 122 relative to the support side plates 13 can be realized.

[0066] Of course, other structural forms can also be used to realize the movement of the two horizontal sliders 121 relative to the fixed seat 11 and the movement of the four vertical sliders 122 relative to the support side plates 13, such as guide rails, which is not limited herein.

[0067] Please refer to Figure 2, in an embodiment of the present invention, the second fixture 2 further includes a lead screw 23 and a driving mechanism (not shown in the figure). The lead screw 23 is disposed between the two bases 21, and the driving mechanism is configured to drive the two bases 21 to approach or separate along the lead screw 23.

[0068] In this embodiment, by providing the lead screw 23 and the driving mechanism, it is convenient to realize the approach or separation of the two bases 21, and the accuracy of the automatic positioning of the two bases 21 can be ensured.

[0069] In some embodiments, the driving mechanism may be, for example, a motor, which is not limited herein.

[0070] In an embodiment of the present invention, the ends of the two bases 21 that approach or separate from each other include an open end 24 and a connection end 25. The lead screw 23 is disposed at the connection end 25. The open end 24 is configured to insert into the fixed seat 11 when the two bases 21 are in a separated state, so as to sleave the two bases 21 on the outer periphery of the fixed seat 11.

[0071] In this embodiment, since the ends of the two bases 21 that approach or separate from each other include an open end 24 and a connection end 25, and the lead screw 23 is disposed at the connection end 25, when a testing machine (not shown in the figure) performs a compression performance test on the specimen 10, it is not convenient for the second fixture 2 to be sleaved onto the outer periphery of the first fixture 1 from above the first fixture 1. Therefore, at this time, the open end 24 can be used to insert into the fixed seat 11 when the two bases 21 are in a separated state, so as to sleave the two bases 21 on the outer periphery of the fixed seat 11.

[0072] Of course, the open end 24 may not be provided, which is not limited herein. That is, at this time, the second fixture 2 can only be sleaved onto the outer periphery of the first fixture 1 from above the first fixture 1.

[0073] In an embodiment of the present invention, the abutting assembly 22 includes four rotatable electric push rods 221. When each electric push rod 221 is in a vertical state, the electric push rod 221 is configured to abut against the vertical slider 122. When each electric push rod 221 is in a horizontal state, the electric push rod 221 is configured to abut against the horizontal slider 121.

[0074] In this embodiment, by providing four rotatable electric push rods 221, it is convenient to realize the pushing of the two horizontal sliders 121 and the four vertical sliders 122, that is, there is no need to provide two sets of push rods (such as a set of horizontal push rods and a set of vertical push rods), so the structure is more simple and compact.

[0075] Of course, two sets of push rods may also be provided, which is not limited herein.

[0076] In an embodiment of the present invention, the second fixture 2 further includes a displacement sensor (not shown in the figure), and the displacement sensor is used to indicate the in-place state of the base 21 and the abutting assembly 22.

[0077] In this embodiment, by providing a displacement sensor, the in-place state of the base 21 and the abutting assembly 22 can be ensured, so that the locking and centering effects on the specimen 10 can be better guaranteed.

[0078] Of course, the displacement sensor may not be provided, and this is not limited herein.

[0079] Please refer to Figure 3 , in an embodiment of the present invention, both the first fixture 1 and the second fixture 2 are located on the lower platen 20 of a testing machine for testing the compressive performance. Arc-shaped grooves 211 are provided at the bottoms of both bases 21, so that when the two bases 21 lock the fixing seat 11, the two arc-shaped grooves 211 are sleeved on the outer periphery of the lower platen 20, thereby realizing the centering of the specimen 10 relative to the lower platen 20.

[0080] In this embodiment, by providing arc-shaped grooves 211 at the bottoms of both bases 21, when the two bases 21 lock the fixing seat 11, the two arc-shaped grooves 211 are sleeved on the outer periphery of the lower platen 20, thereby realizing the centering of the specimen 10 relative to the lower platen 20.

[0081] In addition, an embodiment of the present invention further provides a method for testing the compressive strength after impact of a composite material. Using the system mentioned in any one of the above embodiments, the method includes:

[0082] Placing the specimen 10 in the clamping assembly 12;

[0083] Sleeving the two bases 21 on the outer periphery of the fixing seat 11;

[0084] Bringing the two bases 21 closer to lock the fixing seat 11;

[0085] Abutting the abutting assembly 22 against the clamping assembly 12 to urge the clamping assembly 12 to clamp and center the specimen 10.

[0086] It should be noted that since the method provided in this embodiment and the system provided in the above embodiment belong to the same inventive concept, they have the same beneficial effects, and the beneficial effects of the method embodiment will not be elaborated herein.

[0087] The following introduces the specific test process.

[0088] (1) In the initial state, the specimen 10 is manually placed between the two horizontal sliders 121 and the four vertical sliders 122 of the first fixture 1, and the first fixture 1 containing the specimen 10 is placed on the lower platen 20 of the testing machine.

[0089] (2) The two bases 21 are sleeved on the lower platen 20, the power is turned on, and the two sides of the base 21 are controlled to move closer along the lead screw 23 until the arc groove 211 at the bottom of the base 21 matches the lower platen 20, and the rectangular groove of the base 21 matches the fixed seat 11 of the first fixture 1. At this time, according to the data transmitted by the displacement sensor, the internal power supply of the second fixture 2 stops supplying power to the driving mechanism. The base 21 is locked, and the base 21 and the lower platen 20 are aligned.

[0090] (3) After the base 21 is positioned, the electric push rod 221 is driven to work, first pushing the two horizontal sliders 121 together. When the two horizontal sliders 121 are clamped, the displacement sensor data no longer changes. At this time, the electric push rod 221 is locked, and the mechanical arm drives the electric tightening gun to tighten the first fasteners 14 (such as screws) on the two horizontal sliders 121. Since the electric tightening gun is provided with a torque sensor, when the torque of the first fastener 14 reaches the value required by the test standard, the tightening action is completed, and the two horizontal sliders 121 are fixed.

[0091] (4) After the two horizontal sliders 121 are tightened, the electric push rod 221 is driven to rotate 90 degrees to change from a horizontal state to a vertical state, so that the four vertical sliders 122 can be pushed to clamp synchronously. When the displacement sensor data no longer changes, the electric push rod 221 is locked, and the mechanical arm drives the electric tightening gun to tighten the second fasteners 15 (such as screws) on the four vertical sliders 122. When the torque of the second fastener 15 reaches the value required by the test standard, the tightening action is completed, and the fixation of the four vertical sliders 122 is completed.

[0092] The above steps complete the automated clamping and centering of the test piece 10 .

[0093] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An after-impact compression test system for a composite material, characterized in that, Comprising: A first fixture (1), including a fixed seat (11) and a clamping assembly (12) arranged on the fixed seat (11), the clamping assembly (12) being used for clamping a test piece (10), and the test piece (10) being a composite material laminate; A second fixture (2), including two relatively movable bases (21) and an abutting assembly (22) arranged on the bases (21), the two bases (21) being used for sleeving on the outer periphery of the fixed seat (11) so that when the two bases (21) approach each other, the fixed seat (11) is locked, and the abutting assembly (22) being used for abutting against the clamping assembly (12) to urge the clamping assembly (12) to clamp and center the test piece (10); The first fixture (1) further includes two support side plates (13), the two support side plates (13) being movably arranged on the fixed seat (11), and the test piece (10) being located between the two support side plates (13); The clamping assembly (12) includes two horizontal sliders (121) and four vertical sliders (122), the two horizontal sliders (121) being movably arranged on the fixed seat (11), the test piece (10) being located between the two horizontal sliders (121), wherein two of the vertical sliders (122) are movably arranged on one of the support side plates (13), and the other two vertical sliders (122) are movably arranged on the other support side plate (13), and the test piece (10) being located between the two vertical sliders (122) arranged on the same support side plate (13); Both the first fixture (1) and the second fixture (2) are located on a lower pressing plate (20) of a testing machine for testing compressive performance, and arc-shaped grooves (211) are arranged at the bottoms of the two bases (21) so that when the two bases (21) lock the fixed seat (11), the two arc-shaped grooves (211) are sleeved on the outer periphery of the lower pressing plate (20), thereby realizing the centering of the test piece (10) relative to the lower pressing plate (20); The second fixture (2) further includes a lead screw (23) and a driving mechanism, the lead screw (23) being arranged between the two bases (21), and the driving mechanism being used for driving the two bases (21) to approach or move away along the lead screw (23); The ends of the two bases (21) where they approach or move away from each other include an open end (24) and a connection end (25), the lead screw (23) being arranged at the connection end (25), and the open end (24) being used for inserting into the fixed seat (11) when the two bases (21) are in a separated state to sleeve the two bases (21) on the outer periphery of the fixed seat (11).

2. The system according to claim 1, wherein The two horizontal sliders (121) are connected to the fixed seat (11) through a first fastener (14), and the four vertical sliders (122) are connected to the support side plates (13) through a second fastener (15); The system further includes an electric tightening gun, which is provided with a torque sensor and is used to tighten the first fastener (14) and the second fastener (15); wherein, during the tightening process, when the torque sensor reaches a preset value, the tightening action is stopped.

3. The system according to claim 1, wherein Both of the two horizontal sliders (121) and the four vertical sliders (122) are provided with strip holes (123) to enable movement relative to the fixed seat (11) and the support side plate (13).

4. The system according to claim 1, characterized in that, The abutting assembly (22) includes four rotatable electric push rods (221). When each of the electric push rods (221) is in a vertical state, the electric push rod (221) is used to abut against the vertical slider (122), and when each of the electric push rods (221) is in a horizontal state, the electric push rod (221) is used to abut against the horizontal slider (121).

5. The system according to any one of claims 1-4, characterized in that The second fixture (2) further includes a displacement sensor, which is used to indicate the in-place states of the base (21) and the abutting assembly (22).

6. A method for post - impact compression testing of a composite material, characterized in that, Using the system according to any one of claims 1-5, comprising: Placing the specimen (10) in the clamping assembly (12); Sleeving the two bases (21) on the outer periphery of the fixed seat (11); Bringing the two bases (21) closer together to lock the fixed seat (11); Abutting the abutting assembly (22) against the clamping assembly (12) to prompt the clamping assembly (12) to clamp and center the specimen (10).

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