Composite material tensile sample reinforcing sheet bonding tool and bonding method thereof

Abstract

The invention discloses a composite material tensile sample reinforcing sheet bonding tool and a bonding method thereof. The bonding tool comprises a clamping plate, an upper top plate and a lower top plate, a plurality of screw holes are formed in the edge and the center of the clamping plate, and square cushion blocks with through holes in the centers are arranged at the positions of the screw holes in the two sides of the clamping plate; a plurality of sample grooves are formed in the clamping plate and penetrate through the clamping plate, and the sample grooves are matched with samples in shape; screw holes are formed in the edges and the centers of the upper top plate and the lower top plate; a plurality of reinforcing sheet grooves are symmetrically distributed in the upper sections and the lower sections of the upper ejection plate and the lower ejection plate along the vertical center line respectively, the reinforcing sheet grooves are matched with the sample grooves, a reverse ejection hole is formed in the center of each reinforcing sheet groove, and a glue overflow hole is formed in the corner of each reinforcing sheet groove. By controlling the position between the sample and the reinforcing sheet, fixing the bonding position between the sample and the reinforcing sheet and adopting pressurized demolding, the reinforcing sheet in the obtained composite material tensile sample is precise in bonding and excellent in bonding performance.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material testing, and in particular to a bonding tool for a composite material tensile specimen reinforcement sheet and a bonding method thereof. Background Art

[0002] Composite material tensile testing is an important method for evaluating the mechanical properties of materials. This test applies a tensile load to the composite material to determine parameters such as tensile strength, elastic modulus, yield strength, and elongation, providing a basis for material design and engineering applications. To prevent composite material tensile specimens from being damaged by the clamp during tensile testing, reinforcement plates are bonded to both ends of the composite specimen to prevent premature failure in the clamp. The reinforcement plates disperse the clamping stress and protect the specimen ends, thereby obtaining accurate tensile performance data.

[0003] Currently, most composite tensile specimen bonding fixtures bond the composite sheet's ends together, then process them into standard specimens. This process can easily damage the bonded areas, leading to debonding of the reinforcement sheets during testing, or even directly during processing. Existing techniques often manually bond the reinforcement sheets to the ends of composite tensile specimens. This results in large positional errors between the two sides of a single specimen, and on the same side, making it difficult to ensure accuracy. Furthermore, when external pressure is applied, the reinforcement sheets can easily slip, resulting in asymmetric reinforcement sheets and poor bonding quality. Summary of the Invention

[0004] In response to the problems existing in the above-mentioned background technology, the present invention provides a bonding tool for the reinforcement sheet of a composite material tensile specimen and a bonding method thereof. By controlling the position between the specimen and the reinforcement sheet, fixing the bonding position between the two, and using pressurized demolding, the reinforcement sheet in the obtained composite material tensile specimen is accurately bonded and has excellent bonding performance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A composite material tensile specimen reinforcement sheet bonding tool, comprising a clamping plate and upper and lower top plates of exactly the same shape and size, wherein the upper and lower top plates have exactly the same structure, and the clamping plate is placed between the upper and lower top plates;

[0007] The splint is provided with a plurality of screw holes I along the edge and the center, and a square pad with a through hole in the center is provided at the screw holes I on both sides of the splint. The pad and the splint are processed as one piece, and the through hole of the pad matches the screw hole I and the hole diameter is consistent, so as to control the thickness of the adhesive layer and facilitate demoulding in the later stage.

[0008] The thickness of the pad is 0.1-0.2 mm, and the side length is 1.5-2 times the diameter of the through hole, and the diameter of the through hole is 7-9 mm;

[0009] The clamping plate is provided with a plurality of sample slots symmetrically distributed along the vertical center line. The sample slots penetrate the clamping plate and are located between the screw holes I. The shape of the sample slots matches the composite material tensile test specimen. The spacing between the two middle sample slots is determined according to the side length of the backing plate, and the other sample slots are arranged at equal intervals.

[0010] The thickness of the composite material tensile test specimen is greater than the sum of the depth of the test specimen groove and the thickness of the two pads;

[0011] The spacing between the sample slots is 9 to 11 mm, and the maximum spacing between the two middle sample slots is twice the side length of the spacer block;

[0012] The upper and lower top plates are provided with screw holes II along the edges and in the center, the number and diameter of which are the same as those of the screw holes I, and the positions of the screw holes II on the top plate are consistent with the positions of the screw holes I on the clamping plate; the clamping plate and the upper and lower top plates are locked together by screws passing through the screw holes I and the screw holes II;

[0013] The upper and lower sections of the upper and lower top plates are respectively provided with a plurality of reinforcing sheet grooves symmetrically distributed along the vertical center line, and the reinforcing sheet grooves of the upper and lower sections are symmetrically distributed along the horizontal center line. Every two reinforcing sheet grooves symmetrically distributed on the upper and lower sections match one sample slot, and the shape of the reinforcing sheet groove matches the reinforcing sheet; the top edge of the upper reinforcing sheet groove and the bottom edge of the lower reinforcing sheet groove respectively match the upper and lower edges of the sample slot on the plate;

[0014] The depth of the reinforcement plate groove is 0.2 to 0.3 mm greater than the thickness of the reinforcement plate, and the thickness of the reinforcement plate is determined according to the sample size;

[0015] The dimensions of the reinforcement sheet slots are kept consistent and matched with the dimensions of the sample slots to avoid deviation between the reinforcement sheet and the sample during bonding and pressurization, which may cause the reinforcement sheet to skew.

[0016] A top hole is set in the center of the reinforcing plate slot to facilitate the demoulding of the sample in the later stage; an overflow hole is set at the corner of each reinforcing plate slot to ensure the outflow of excess adhesive and facilitate the subsequent cleaning of excess adhesive;

[0017] The diameter of the reverse top hole is 7-9 mm, and the diameter of the glue overflow hole is 3-4 mm;

[0018] The overflow hole is used to reduce the adhesive residue in the reinforcement sheet slot and the sample slot. If the overflow hole is too small, it will affect the extrusion of the glue liquid, and if it is too large, it will affect the stability of the reinforcement sheet.

[0019] Furthermore, a screw hole is provided at each corner of the splint, the center of each side, and the center of the splint.

[0020] In the present invention, the bonding position is fixed by the sample groove and the reinforcement sheet groove, ensuring that there will be no problems of inaccurate positioning such as slippage during bonding; the bonding of a single sample ensures the bonding quality and will not cause the reinforcement sheet to become detached due to processing.

[0021] Furthermore, the present invention also provides a method for bonding a composite material tensile specimen reinforcement sheet using the above-mentioned bonding method, comprising the following steps:

[0022] (1) Apply release agent evenly on the surface and grooves of the splint and upper and lower top plates to facilitate demoulding and cleaning;

[0023] (2) Cut a reinforcement sheet that matches the shape and size of the composite material tensile specimen, and grind the bonding surface on one side of the reinforcement sheet and the upper and lower bonding areas on both sides of the tensile specimen to make them rough and clean;

[0024] (3) Paste double-sided tape in the reinforcement sheet grooves of the upper and lower top plates, and adhere the non-adhesive side of the reinforcement sheet to the reinforcement sheet groove. Use the reinforcement sheet groove to control the position of the reinforcement sheet to avoid slippage during bonding and pressurization; evenly apply the adhesive to the adhesive surface of the reinforcement sheet of the lower top plate;

[0025] (4) Insert the screws into all the screw holes of the lower top plate one by one, and then place the splint through the screw holes and the screws on the lower top plate;

[0026] (5) Process the sample into the standard specimen size to avoid damage or detachment of the reinforcement sheet when processing it into the standard specimen after overall bonding. Apply adhesive evenly on both sides and the bonding area on the same side of the standard composite tensile specimen and place it in the specimen slot;

[0027] (6) Apply adhesive evenly to the bonding surface of the reinforcement sheet of the upper top plate, then place the upper top plate on the clamping plate through the screw holes and screws, and lock the upper and lower top plates and the clamping plate with the screws;

[0028] Use a 30Nm torque wrench to evenly install and tighten the screws one by one. Then use four C-clamps to clamp the four reinforcement plate bonding areas symmetrically distributed along the center on both sides of the upper and lower top plates to apply pressure to the upper and lower top plates.

[0029] (7) The top plate and the clamping plate after the mold is closed in step (6) are subjected to a curing reaction, and pressure is applied to the upper and lower top plates during the curing process, and each reinforcement plate is subjected to uniform force; after the curing is completed, the upper and lower top plates are removed along the gap between the clamping plate and the pads in the upper and lower top plates, and the sample is ejected from the anti-top hole and demolded;

[0030] The curing reaction is performed at room temperature for 24 hours or at 75°C for 5 hours;

[0031] If the upper and lower top plates are difficult to remove, screw the screws with the same diameter as the top holes into the top holes to push out the upper and lower top plates and demould them.

[0032] (8) After demoulding, the excess glue is polished to obtain a standard tensile test specimen of the composite material with the bonding reinforcement sheet;

[0033] The excess glue is squeezed out from both sides of the reinforcing sheet and polished with sandpaper;

[0034] The adhesive is an epoxy adhesive, which is composed of epoxy resin and curing agent in a mass ratio of 2 to 3:1.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The present invention controls the position between the sample and the reinforcing sheet through the sample groove and the reinforcing sheet groove, ensuring that no relative movement occurs during the bonding and pressurization process, thereby improving the positioning accuracy and bonding quality of the bonding reinforcing sheet;

[0037] (2) During the curing process, pressure is applied to the upper and lower top plates to ensure that each reinforcement sheet is evenly stressed. The adhesive residue in the reinforcement sheet groove and the sample groove is reduced through the overflow hole to ensure that excess adhesive flows out during the pressurization process, which is convenient for subsequent cleaning of the residual adhesive;

[0038] (3) By setting pads to control the thickness of the rubber layer of the reinforcing sheets on both sides, a gap is left between the plywood and the upper and lower top plates to facilitate the demoulding operation;

[0039] (4) The bonding process of the present invention can form a set of standard specimens at one time. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a top view of the splint structure in the bonding tooling of the present invention.

[0041] Figure 2 This is a top view of the upper and lower top plate structures in the bonding tooling of the present invention.

[0042] Figure 3 This is a side view of the overall structure of the upper and lower top plates and clamping plates in the bonding tooling of the present invention after mold closing.

[0043] The markings in the figure are: 1 clamping plate, 2 upper and lower top plates, 3 specimen slot, 4 reinforcement plate slot, 5 spacer, 6 screw hole I, 7 anti-top hole, 8 glue overflow hole, 9 screw hole II. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] Example

[0046] The present invention discloses a composite material tensile specimen reinforcement sheet bonding tool, comprising a clamping plate 1 and upper and lower top plates 2 of identical shape and size. The upper and lower top plates have identical structural arrangements, and the clamping plate is placed between the upper and lower top plates. The clamping plate is 1.6 mm thick.

[0047] The plywood 1 is provided with a plurality of screw holes Ⅰ 6 along the edge and the center, and a square pad 5 with a through hole in the center is provided at the screw holes Ⅰ on both sides of the plywood. The pad and the plywood are processed as one piece, and the through hole of the pad matches the screw hole Ⅰ and the hole diameter is consistent, so as to control the thickness of the adhesive layer and facilitate the demoulding in the later stage.

[0048] The pad has a thickness of 0.1 mm, a side length of 15 mm, and a through hole diameter of 8 mm;

[0049] The clamping plate is provided with a plurality of sample slots 3 symmetrically distributed along the vertical center line. The sample slots penetrate the clamping plate and are located between the screw holes I. The shape of the sample slots matches the composite material tensile test specimen. The spacing between the two middle sample slots is determined according to the side length of the backing plate, and the other sample slots are arranged at equal intervals.

[0050] The thickness of the composite tensile test specimen is greater than the sum of the depth of the test specimen groove and the thickness of the two pads. The test specimen thickness is 2 mm and the depth of the test specimen groove is 1.6 mm.

[0051] The spacing between the sample slots is 10 mm, and the maximum spacing between the two middle sample slots is 30 mm;

[0052] The upper and lower top plates are provided with screw holes II 9 along the edges and in the center, the number and diameter of which are the same as those of the screw holes I 6, and the position of the screw holes II in the top plate is consistent with the position of the screw holes I in the clamping plate; the clamping plate and the upper and lower top plates are locked by screws passing through the screw holes I and the screw holes II;

[0053] The upper and lower sections of the upper and lower top plates are respectively provided with a plurality of reinforcing sheet grooves 4 symmetrically distributed along the vertical center line, and the reinforcing sheet grooves of the upper and lower sections are symmetrically distributed along the horizontal center line. Every two symmetrically distributed reinforcing sheet grooves of the upper and lower sections match one sample slot, and the shape of the reinforcing sheet groove matches the reinforcing sheet; the top edge of the upper reinforcing sheet groove and the bottom edge of the lower reinforcing sheet groove respectively match the upper and lower edges of the sample slot on the plate;

[0054] The reinforcement plate groove depth is 2.2mm, and the reinforcement plate thickness is 2mm;

[0055] The dimensions of the reinforcement sheet slots are kept consistent and matched with the dimensions of the sample slots to avoid deviation between the reinforcement sheet and the sample during bonding and pressurization, which may cause the reinforcement sheet to skew.

[0056] A top hole 7 is provided at the center of each reinforcing sheet slot to facilitate the demoulding of the sample in the later stage; an overflow hole 8 is provided at each corner of each reinforcing sheet slot to ensure the outflow of excess adhesive and facilitate the subsequent cleaning of excess adhesive;

[0057] The diameter of the reverse top hole is 8mm, and the diameter of the glue overflow hole is 4mm;

[0058] The overflow hole is used to reduce the adhesive residue in the reinforcement sheet slot and the sample slot. If the overflow hole is too small, it will affect the extrusion of the glue liquid, and if it is too large, it will affect the stability of the reinforcement sheet.

[0059] A screw hole is respectively provided at the corner of the splint, the center of each side and the center of the splint.

[0060] In the present invention, the bonding position is fixed by the sample slot and the reinforcement sheet slot, ensuring that there will be no slipping or other positioning problems during bonding; the bonding of a single sample ensures that the bonding quality will not be affected by the reinforcement sheet falling off due to processing.

[0061] A method for bonding a composite material tensile specimen reinforcement sheet using the above-mentioned bonding process comprises the following steps:

[0062] (1) Apply release agent evenly on the surface and grooves of the splint and upper and lower top plates to facilitate demoulding and cleaning;

[0063] (2) Cut a reinforcement sheet that matches the shape and size of the composite material tensile specimen, and grind the bonding surface on one side of the reinforcement sheet and the upper and lower bonding areas on both sides of the tensile specimen to make them rough and clean;

[0064] (3) Paste double-sided tape in the reinforcement sheet grooves of the upper and lower top plates, and adhere the non-adhesive side of the reinforcement sheet to the reinforcement sheet groove. Use the reinforcement sheet groove to control the position of the reinforcement sheet to avoid slippage during bonding and pressurization; evenly apply the adhesive to the adhesive surface of the reinforcement sheet of the lower top plate;

[0065] (4) Insert the screws into all the screw holes of the lower top plate one by one, and then place the splint through the screw holes and the screws on the lower top plate;

[0066] (5) Process the sample into the standard specimen size to avoid damage or detachment of the reinforcement sheet when processing it into the standard specimen after overall bonding. Apply adhesive evenly on both sides and the bonding area on the same side of the standard composite tensile specimen and place it in the specimen slot;

[0067] (6) Apply adhesive evenly to the bonding surface of the reinforcement sheet of the upper top plate, then place the upper top plate on the clamping plate through the screw holes and screws, and lock the upper and lower top plates and the clamping plate with the screws;

[0068] Use a 30Nm torque wrench to evenly install and tighten the screws one by one. Then use four C-clamps to clamp the four reinforcement plate bonding areas symmetrically distributed along the center on both sides of the upper and lower top plates to apply pressure to the upper and lower top plates.

[0069] (7) The top plate and the clamping plate after the mold is closed in step (6) are subjected to a curing reaction, and pressure is applied to the upper and lower top plates during the curing process, and each reinforcement plate is subjected to uniform force; after the curing is completed, the upper and lower top plates are removed along the gap between the clamping plate and the pads in the upper and lower top plates, and the sample is ejected from the anti-top hole and demolded;

[0070] The curing reaction is performed at room temperature for 24 hours;

[0071] Use Φ8 screws to screw into the counter-top holes to push out the upper and lower top plates and demould them;

[0072] (8) After demoulding, the excess glue is polished to obtain a standard tensile test specimen of the composite material with the bonding reinforcement sheet;

[0073] The excess glue is squeezed out from both sides of the reinforcing sheet and polished with sandpaper;

[0074] The adhesive is an epoxy adhesive, which is composed of epoxy resin and curing agent in a mass ratio of 2:1.

[0075] The present invention controls the position between the sample and the reinforcing sheet through the sample groove and the reinforcing sheet groove, ensures that no relative movement occurs during the bonding and pressurizing process, and improves the positioning accuracy and bonding quality of the bonding reinforcing sheet; reduces the residual adhesive in the reinforcing sheet groove and the sample groove through the overflow hole, controls the thickness of the reinforcing sheet glue layer on both sides by setting the pad, and leaves a gap between the clamping plate and the upper and lower top plates to facilitate the demoulding operation.

Claims

1. A composite material tensile specimen reinforcement sheet bonding tool, characterized in that: It comprises a clamping plate (1) and upper and lower top plates (2) of exactly the same shape and size. The upper and lower top plates have exactly the same structural arrangement, and the clamping plate (1) is placed between the upper and lower top plates (2). The splint (1) is provided with a plurality of screw holes I (6) along the edge and the center, and a square pad (5) with a through hole in the center is provided at the screw holes I (6) on both sides of the splint. The pad (5) and the splint (1) are processed as a whole, and the through hole of the pad matches the screw hole I and the hole diameter is consistent; A plurality of sample slots (3) are symmetrically arranged along a vertical center line on the clamping plate (1), the sample slots (3) pass through the clamping plate (1), the sample slots (3) are located between the screw holes I (6), and the shape of the sample slots matches the composite material tensile test specimen; the spacing between the two middle sample slots is determined according to the side length of the backing plate, and the other sample slots are arranged at equal intervals; The thickness of the composite material tensile test specimen is greater than the sum of the depth of the test specimen groove and the thickness of the two pads; The upper and lower top plates are provided with screw holes II (9) along the edges and in the centers thereof, the number and diameter of which are the same as those of the screw holes I, and the positions of the screw holes II (9) on the top plate are the same as those of the screw holes I (6) on the clamping plate; the clamping plate and the upper and lower top plates are locked with screws passing through the screw holes I and the screw holes II; The upper and lower sections of the upper and lower top plates are respectively provided with a plurality of reinforcing sheet grooves (4) symmetrically distributed along the vertical center line, and the reinforcing sheet grooves (4) of the upper and lower sections are symmetrically distributed along the horizontal center line, and every two reinforcing sheet grooves (4) symmetrically distributed in the upper and lower sections match one sample groove (3), and the shape of the reinforcing sheet groove matches the reinforcing sheet; the top edge of the upper reinforcing sheet groove and the bottom edge of the lower reinforcing sheet groove respectively match the upper and lower edges of the sample groove on the plate; A top hole (7) is provided at the center of each reinforcing plate slot (4); A glue overflow hole (8) is provided at each corner of each reinforcement plate slot (4).

2. The composite material tensile specimen reinforcement sheet bonding tool according to claim 1, characterized in that: The pad has a thickness of 0.1 to 0.2 mm and a side length of 1.5 to 2 times the diameter of the through hole, and the diameter of the through hole is 7 to 9 mm.

3. The composite material tensile specimen reinforcement sheet bonding tool according to claim 1, characterized in that: The spacing between the sample slots is 9 to 11 mm, and the maximum spacing between the two middle sample slots is twice the side length of the pad.

4. The composite material tensile specimen reinforcement sheet bonding tool according to claim 1, characterized in that: The depth of the reinforcement plate groove is 0.2 to 0.3 mm greater than the thickness of the reinforcement plate, and the thickness of the reinforcement plate is determined according to the sample size.

5. The composite material tensile specimen reinforcement sheet bonding tool according to claim 1, characterized in that: The diameter of the reverse top hole is 7-9 mm, and the diameter of the glue overflow hole is 3-4 mm.

6. The composite material tensile specimen reinforcement sheet bonding tool according to claim 1, characterized in that: A screw hole is respectively provided at the corner of the splint, the center of each side and the center of the splint.

7. A method for bonding a composite material tensile test specimen reinforcement sheet using the bonding method according to any one of claims 1 to 6, characterized in that: The steps include: (1) Apply release agent evenly on the surface and grooves of the splint and upper and lower top plates to facilitate demoulding and cleaning; (2) Cut a reinforcement sheet that matches the shape and size of the composite material tensile specimen, and grind the bonding surface on one side of the reinforcement sheet and the upper and lower bonding areas on both sides of the tensile specimen to make them rough and clean; (3) Paste double-sided tape in the reinforcement sheet grooves of the upper and lower top plates, adhere the non-adhesive side of the reinforcement sheet to the reinforcement sheet groove, control the position of the reinforcement sheet through the reinforcement sheet groove, and evenly apply the adhesive to the adhesive surface of the reinforcement sheet of the lower top plate; (4) Insert the screws into all the screw holes of the lower top plate one by one, and then place the splint through the screw holes and the screws on the lower top plate; (5) Process the sample into the standard sample size, apply adhesive evenly on both sides of the standard composite material tensile specimen and the bonding area on the same side, and place it in the sample slot; (6) Apply adhesive evenly to the bonding surface of the reinforcement sheet of the upper top plate, then place the upper top plate on the clamping plate through the screw holes and screws, and lock the upper and lower top plates and the clamping plate with the screws; Use a 30Nm torque wrench to evenly install and tighten the screws one by one. Then use four C-clamps to clamp the four reinforcement plate bonding areas symmetrically distributed along the center on both sides of the upper and lower top plates to apply pressure to the upper and lower top plates. (7) The top plate and the clamping plate after the mold is closed in step (6) are subjected to a curing reaction, and pressure is applied to the upper and lower top plates during the curing process, and each reinforcement plate is subjected to uniform force; after the curing is completed, the upper and lower top plates are removed along the gap between the clamping plate and the pads in the upper and lower top plates, and the sample is ejected from the anti-top hole and demolded; The curing reaction is performed at room temperature for 24 hours or at 75°C for 5 hours; (8) After demoulding, the excess glue is polished to obtain a standard tensile test specimen of the composite material with the bonding reinforcement sheet; The excess glue is squeezed out from both sides of the reinforcing sheet and polished with sandpaper.

8. The bonding method according to claim 7, characterized in that: In step (7), screws with the same diameter as the anti-top holes are screwed into the anti-top holes to eject the upper and lower top plates from the mold.

9. The bonding method according to claim 7, characterized in that: The adhesive is an epoxy adhesive, which is composed of epoxy resin and curing agent in a mass ratio of 2 to 3:1.

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